⚔️ Black Trigram (흑괘)

May 24, 2026 · View on GitHub

Last Updated: 2026-04-28
Architecture Version: 2.1 (Production-Ready)
Product Version: 0.7.32
Status: ✅ 13/13 Combat Realism Systems Complete (100%)
🔐 ISMS Alignment: This document follows the Hack23 Secure Development Policy for secure system architecture documentation, and references the Threat Modeling Policy and Information Security Policy.

2D Realistic Precision Combat Simulator rooted in Korean martial arts and I Ching philosophy.

Audio-Visual Feedback: 국악 (traditional Korean instruments) blended with cyberpunk aesthetics for immersive combat cues.
Anatomical Targeting: 70 vital points with realistic damage calculation
Cultural Authenticity: Traditional Korean martial arts with modern implementation
Dark Ops Integration: 15 specialized techniques from Korean special operations units
Injury-Based Movement Penalties: Realistic leg/body damage affects movement speed and stance changes

Latest Update:

December 2024: Added Dark Ops unit combat techniques (암흑작전부대 기술) for tactical assassination and silent incapacitation methods used by Korean special operations forces.
December 2024: Implemented Injury-Based Movement Penalty System (이동 패널티 시스템) for realistic leg damage affecting mobility, stance changes, and balance.
Q1 2026: Completed comprehensive documentation of all 70 vital points across 4 anatomical systems with damage calculation examples.
January 2026: ✨ Integrated Grappling System (잡기 체계) with authentic Hapkido/Ssireum techniques, 4 animation states, and grip mechanics.
January 2026: ✨ Integrated Limb Exposure & Counter-Attack System (사지 노출 및 반격 체계) with AI decision integration, visual indicators, and 132 comprehensive tests.

Core Systems

🔧 Core Combat System Architecture - System overview and architecture diagram
☰ Trigram Combat System - 8 stance system with I Ching philosophy
🎯 Vital Point Targeting System - 70 vital points overview
🤜 Grappling System - ✨ NEW: Hapkido/Ssireum grappling with grip decay and escape mechanics
⚡ Limb Exposure & Counter-Attacks - ✨ NEW: Vulnerability windows with AI integration

Complete 70 Vital Points Documentation

💀 Complete 70 Vital Points System - NEW: All 70 vital points organized by anatomical system
- 🧠 Nervous System (25 points) - Paralysis, unconsciousness, stunning
- 🩸 Circulatory System (15 points) - Blood flow disruption, hemorrhage
- 🫁 Respiratory System (10 points) - Breathing disruption, suffocation
- 🦴 Musculoskeletal System (20 points) - Joint locks, bone strikes, mobility loss

Combat Mechanics

⚙️ Damage Calculation System - NEW: Complete damage formulas with 3 worked examples
🦴 28-Bone Skeletal Animation - NEW: Skeletal rig with 7 hand poses
💊 Status Effect System - NEW: 5 status effects (Stun, Bleed, Fatigue, Paralysis, Disorientation)
🤖 Combat AI Behavior - NEW: AI decision trees and vital point selection logic
⚡ Performance Optimization - NEW: 60fps optimization techniques
⚖️ Balance Considerations - NEW: Game balance philosophy and tuning guidelines

Player Systems

👤 Player Archetype Combat Specializations - 5 fighter archetypes
🌑 Dark Ops Unit Combat Techniques - 15 specialized assassination techniques
🦵 Injury-Based Movement Penalty System - Realistic damage affecting mobility
🧬 Physical Attributes System - Stats and attribute mechanics

Animation Systems

🥋 Fighting Stance Guard Animation System - Defensive stance animations
🎬 Complete Animation Coverage System - Full combat animation catalog
🔄 Stance Transition Animation System - Trigram stance transitions
🤕 Fall Down Animation System - Knockdown and fall animations
🏃 Recovery Animation System - Getting up from knockdown

Implementation

🎮 Combat Component Architecture - Component structure
🔊 Audio System Integration - Korean traditional music integration
📊 Type System Foundation - TypeScript interfaces
🚀 Implementation Priority Matrix - Development roadmap
💡 Technical Specifications - Performance and cultural standards
🎯 Success Metrics - Combat effectiveness goals

External References

docs/vital-points/VITAL_POINTS_REFERENCE.md - Complete anatomical documentation with TCM meridian associations
docs/combat/damage-calculation-guide.md - Quick-reference damage calculation overview and formulas
game-design.md - Overall game design document
ARCHITECTURE.md - System architecture overview
game-status.md - Current implementation status

Below, we define the Combat System's architecture in detail.

🔧 Core Combat System Architecture

%%{init: {'theme':'base', 'themeVariables': {'primaryColor':'#2979FF','primaryTextColor':'#fff','primaryBorderColor':'#0D47A1','lineColor':'#00C853','secondaryColor':'#FFD600','tertiaryColor':'#FF3D00'}}}%%
graph TB
    subgraph "Combat System Controller (src/systems/CombatSystem.ts)"
        CSC[CombatSystemController]:::core
        CSC --> TCS[TrigramSystemFactory]:::trigram
        CSC --> VPS[VitalPointSystemFactory]:::vital
        CSC --> KTS[KoreanTechniqueSystemFactory]:::tech
        CSC --> DCS[DamageCalculationEngine]:::damage
        CSC --> AFS[AudioFeedbackSystem]:::audio
    end

    subgraph "Type System Foundation"
        TS[Type System]:::types
        TS --> CT[Combat Types]:::types
        TS --> PT[Player Types]:::types
        TS --> AT[Anatomy Types]:::types
        TS --> TT[Trigram Types]:::types
        TS --> AuT[Audio Types]:::types
    end

    subgraph "Trigram Combat Engine (src/systems/TrigramSystem.ts)"
        TCS --> SM[StanceManager]:::trigram
        TCS --> TC[TrigramCalculator]:::trigram
        TCS --> TR[TransitionCalculator]:::trigram
        TCS --> KC[KoreanCulture]:::trigram
        TCS --> KT[KoreanTechniques]:::trigram
    end

    subgraph "Vital Point System (src/systems/VitalPointSystem.ts)"
        VPS --> KA[KoreanAnatomy]:::vital
        VPS --> KVP[KoreanVitalPoints]:::vital
        VPS --> AR[AnatomicalRegions]:::vital
        VPS --> HD[HitDetection]:::vital
        VPS --> DC[DamageCalculator]:::vital
    end

    subgraph "Component Layer"
        CMP[Combat Components]:::components
        CMP --> CS[CombatScreen]:::components
        CMP --> CA[CombatArena]:::components
        CMP --> CH[CombatHUD]:::components
        CMP --> CC[CombatControls]:::components
    end

    classDef core fill:#00ffd0,stroke:#333,color:#000,stroke-width:3px
    classDef trigram fill:#ffd700,stroke:#333,color:#000,stroke-width:2px
    classDef vital fill:#ff6b6b,stroke:#333,color:#000,stroke-width:2px
    classDef tech fill:#4caf50,stroke:#333,color:#000,stroke-width:2px
    classDef damage fill:#ff8c00,stroke:#333,color:#000,stroke-width:2px
    classDef audio fill:#87CEFA,stroke:#333,color:#000,stroke-width:2px
    classDef types fill:#9370db,stroke:#333,color:#000,stroke-width:2px
    classDef components fill:#32cd32,stroke:#333,color:#000,stroke-width:2px

    CSC -.->|uses| TS
    CMP -.->|implements| CSC

🎯 Combat System Controller Architecture

CombatSystemController (src/systems/CombatSystem.ts):
- Status: Currently empty, needs full implementation
- Planned Methods:
  - executeKoreanTechnique(attacker, techniqueName, target): Execute authentic Korean martial arts techniques
  - calculateTrigramAdvantage(attackerStance, defenderStance): I Ching-based stance effectiveness
  - processVitalPointHit(targetState, hitPosition, technique): Anatomical damage calculation
  - validateTechnique(playerState, techniqueName): Check stance compatibility and resources
  - update(deltaTime, playerInputs): 60 FPS combat state advancement

☰ Trigram Combat System (팔괘 무술 체계)

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graph LR
    subgraph "Eight Trigram Stances (팔괘)"
        G["☰ 건 Geon<br/>Heaven"]:::geon
        T["☱ 태 Tae<br/>Lake"]:::tae
        L["☲ 리 Li<br/>Fire"]:::li
        J["☳ 진 Jin<br/>Thunder"]:::jin
        S["☴ 손 Son<br/>Wind"]:::son
        GA["☵ 감 Gam<br/>Water"]:::gam
        GN["☶ 간 Gan<br/>Mountain"]:::gan
        GO["☷ 곤 Gon<br/>Earth"]:::gon
    end

    subgraph "Trigram System Components"
        SM[StanceManager]:::sys
        TC[TrigramCalculator]:::sys
        TR[TransitionCalculator]:::sys
        KT[KoreanTechniques]:::sys
    end

    G --> SM
    T --> SM
    L --> SM
    J --> SM
    S --> SM
    GA --> SM
    GN --> SM
    GO --> SM

    SM --> TC
    TC --> TR
    TR --> KT

    classDef geon fill:#ffd700,stroke:#333,color:#000
    classDef tae fill:#87ceeb,stroke:#333,color:#000
    classDef li fill:#ff4500,stroke:#333,color:#fff
    classDef jin fill:#9370db,stroke:#333,color:#fff
    classDef son fill:#98fb98,stroke:#333,color:#000
    classDef gam fill:#4169e1,stroke:#333,color:#fff
    classDef gan fill:#8b4513,stroke:#333,color:#fff
    classDef gon fill:#654321,stroke:#333,color:#fff
    classDef sys fill:#333,stroke:#ffd700,color:#ffd700,stroke-width:2px

Current Implementation Status:

StanceManager (src/systems/trigram/StanceManager.ts): ❌ Empty - needs full implementation
TrigramCalculator (src/systems/trigram/TrigramCalculator.ts): ❌ Empty - needs stance effectiveness matrix
TransitionCalculator (src/systems/trigram/TransitionCalculator.ts): ❌ Empty - needs Ki/Stamina cost calculation
KoreanTechniques (src/systems/trigram/KoreanTechniques.ts): ❌ Empty - needs authentic technique database
KoreanCulture (src/systems/trigram/KoreanCulture.ts): ❌ Empty - needs cultural context system

🥋 Fighting Stance Guard Animation System (자세 방어 애니메이션)

Added: January 2025 - Authentic Korean martial arts guard positions with breathing animations

The Fighting Stance Guard Animation System provides stance-specific defensive postures for all 8 trigram stances, implementing authentic Korean martial arts guard positions with realistic breathing animations at 60fps.

Guard Pose Architecture

Each of the 8 trigram stances has a unique default guard pose that reflects traditional Korean martial arts positioning:

interface StanceGuardPose {
  leftArm: { shoulder: Euler; elbow: Euler; wrist: Euler };
  rightArm: { shoulder: Euler; elbow: Euler; wrist: Euler };
  torso: Euler;
  weight: 'forward' | 'neutral' | 'back';
  breathingRange: { min: number; max: number };
}

Eight Trigram Guard Positions

Trigram	Korean	Guard Type	Weight	Breathing	Martial Arts Basis
☰ 건	Heaven	High Guard	Forward	6 frames	Taekwondo Ap Seogi
☱ 태	Lake	Fluid Mid-Guard	Forward	6 frames	Taekwondo Ap Koobi Seogi
☲ 리	Fire	Aggressive Forward	Neutral	4 frames	Taekwondo Juchum Seogi
☳ 진	Thunder	Explosive Ready	Back	5 frames	Taekwondo Dwi Koobi Seogi
☴ 손	Wind	Continuous Motion	Neutral	6 frames	Taekwondo Niunja Seogi
☵ 감	Water	Flowing Defensive	Neutral	6 frames	Taekwondo Narani Seogi
☶ 간	Mountain	Solid Defensive	Neutral	4 frames	Taekwondo Gibo Seogi
☷ 곤	Earth	Grounded Low	Neutral	5 frames	Taekwondo Joong Ha Seogi

Animation State Integration

%%{init: {'theme':'base', 'themeVariables': {'primaryColor':'#2979FF','primaryTextColor':'#fff','primaryBorderColor':'#0D47A1','lineColor':'#00C853','secondaryColor':'#FFD600','tertiaryColor':'#FF3D00'}}}%%
graph LR
    subgraph "Guard Animation States"
        SG1[stance_guard_geon]:::guard
        SG2[stance_guard_tae]:::guard
        SG3[stance_guard_li]:::guard
        SG4[stance_guard_jin]:::guard
        SG5[stance_guard_son]:::guard
        SG6[stance_guard_gam]:::guard
        SG7[stance_guard_gan]:::guard
        SG8[stance_guard_gon]:::guard
    end

    subgraph "Combat Actions"
        ATK[Attack]:::action
        DEF[Defend]:::action
        MOV[Movement]:::action
    end

    subgraph "Stance System"
        SC[Stance Change<br/>600ms]:::stance
    end

    SG1 --> ATK
    SG2 --> ATK
    SG1 --> DEF
    SG1 --> MOV
    SG1 --> SC
    ATK --> SG1
    DEF --> SG1
    MOV --> SG1
    SC --> SG1

    classDef guard fill:#00ffd0,stroke:#333,color:#000,stroke-width:2px
    classDef action fill:#ff6b6b,stroke:#333,color:#fff,stroke-width:2px
    classDef stance fill:#ffd700,stroke:#333,color:#000,stroke-width:2px

Breathing Animation System

Each guard implements authentic martial arts breathing patterns:

Breathing Frame Counts:

Power Stances (Heaven, Thunder, Earth): 5-6 frames for deep breathing
Precision Stances (Fire, Mountain): 4 frames for controlled breathing
Fluid Stances (Lake, Wind, Water): 6 frames for flowing breathing

Breathing Range:

Min: 0.96-0.99 (inhale, chest expansion)
Max: 1.01-1.04 (exhale, chest contraction)
Target FPS: 60fps for smooth animation

Implementation Files

Core System:

src/systems/animation/StanceGuardPoses.ts - Guard pose configurations (8 stances)
src/systems/animation/AnimationStateMachine.ts - State machine with guard support
src/systems/animation/AnimationTransitions.ts - Guard transition rules (264 rules)
src/types/skeletal.ts - Guard pose type definitions

Helper Methods:

// Transition to stance-specific guard
machine.transitionToStanceGuard(TrigramStance.GEON);

// Check if in guard state
if (machine.isInStanceGuard()) {
  const currentGuardStance = machine.getCurrentGuardStance();
}

// Get guard pose for rendering
const guardPose = getGuardPoseForStance(TrigramStance.LI);

Korean Martial Arts Authenticity

Each guard position is based on traditional Korean martial arts stances (자세):

☰ 건 (Geon) - Heaven: High guard based on 앞서기 (Ap Seogi - Walking Stance)

Hands raised to shoulder level or above
Weight 60% forward for aggressive positioning
Ready for overhead strikes and bone-breaking techniques
Breathing emphasizes chest expansion for power generation

☱ 태 (Tae) - Lake: Fluid mid-guard based on 앞굽이 (Ap Koobi Seogi - Front Stance)

Hands at mid-level (chest height)
Extended reach for joint locks and throws (+15% reach bonus)
Weight forward for throwing leverage
Smooth flowing breathing for continuous adaptation

☲ 리 (Li) - Fire: Aggressive forward guard based on 주춤 (Juchum Seogi - Horse Stance)

Hands forward in striking position
Low center of gravity for stability (+15% stability vs vital strikes)
Neutral weight but ready to explode forward
Controlled shallow breathing for precision (+5% crit chance)

☳ 진 (Jin) - Thunder: Explosive ready stance based on 뒤굽이 (Dwi Koobi Seogi - Back Stance)

Hands chambered high for explosive release
Weight 70% back for sudden forward burst
Ready for shocking nerve strikes (+15% shock damage)
Deep breathing for power generation

☴ 손 (Son) - Wind: Continuous motion guard based on 니은자 (Niunja Seogi - L-Stance)

Hands in flowing circular pattern
Neutral weight for lateral movement (+10% lateral mobility)
Ready for pressure point sequences (+10% chaining speed)
Rhythmic breathing for sustained combos

☵ 감 (Gam) - Water: Flowing defensive guard based on 나란이 (Narani Seogi - Parallel Stance)

Hands low and flowing
Centered weight for adaptability (+10% counter speed)
Ready for counter-grappling and sweeps
Deep flowing breathing for counter-attacks (+15 bleed on rib shots)

☶ 간 (Gan) - Mountain: Solid defensive posture based on 기본 (Gibo Seogi - Basic Stance)

Arms in tight defensive position
Balanced weight for maximum stability (+15% block strength)
Immovable blocking stance (+10% counter-strike speed)
Minimal steady breathing for endurance

☷ 곤 (Gon) - Earth: Grounded low guard based on 중하 (Joong Ha Seogi - Deep Stance)

Hands very low for ground control
Low center of gravity (+20% ground-control advantage)
Ready for throws and takedowns (+20 bleed on takedowns)
Deep diaphragm breathing for explosive power

Transition Rules

Guard → Combat Actions:

Guards can transition to attack, defend, stance_change
Guards can be interrupted by hit, ko (high priority)
Guards can transition to movement (walk, run)

Combat Actions → Guard:

After non-looping animations complete, returns to idle (not guard)
Explicit guard transition required via transitionToStanceGuard()
Stance change (600ms) can lead to new guard

Guard ↔ Guard:

Direct transitions between guards allowed (instant guard change)
Useful for rapid stance adaptation without full stance_change animation
Example: stance_guard_geon → stance_guard_tae (immediate switch)

Performance Characteristics

Animation Performance:

Frame Rate: 60fps breathing animations
Transition Time: <1ms for guard switching
Memory Usage: Minimal (8 guard configs cached)
Test Coverage: 166 tests (97 pose validation + 40 transition + 29 state machine)

Integration Points:

SkeletalPlayer3D: Ready for skeletal rig rendering
StanceManager: Hook for trigram system integration
CombatHUD: Guard position indicators prepared

Implementation Status

Feature	Status	Tests	Coverage
Guard Pose Definitions	✅ Complete	97	100%
Animation State Machine	✅ Complete	40	100%
Transition Rules	✅ Complete	29	100%
Korean Martial Arts Accuracy	✅ Complete	97	100%
Breathing Animation Logic	✅ Complete	40	100%
SkeletalPlayer3D Integration	📋 Pending	-	-
UI Guard Indicators	📋 Pending	-	-
Visual Demo Component	📋 Pending	-	-

Code Example

import { 
  PlayerAnimationStateMachine, 
  DEFAULT_ANIMATION_CONFIGS,
  getGuardPoseForStance 
} from '@/systems/animation';
import { TrigramStance } from '@/types/common';

// Initialize animation state machine
const machine = new PlayerAnimationStateMachine(DEFAULT_ANIMATION_CONFIGS);

// When player enters Fire stance (리)
const playerStance = TrigramStance.LI;
machine.transitionToStanceGuard(playerStance);

// Get current guard pose for rendering
if (machine.isInStanceGuard()) {
  const guardStance = machine.getCurrentGuardStance(); // Returns "li"
  const guardPose = getGuardPoseForStance(guardStance);
  
  // Apply to skeletal rig
  applyArmRotations(skeletalRig, guardPose.leftArm, guardPose.rightArm);
  applyTorsoRotation(skeletalRig, guardPose.torso);
  
  // Update breathing animation
  const breathScale = interpolate(
    guardPose.breathingRange.min,
    guardPose.breathingRange.max,
    machine.getCurrentFrame() / machine.getCurrentAnimation().frames
  );
  applyBreathingScale(skeletalRig, breathScale);
}

// In game loop (useFrame)
useFrame((state, delta) => {
  const result = machine.update(delta);
  
  if (result.justStarted && machine.isInStanceGuard()) {
    // Guard just activated
    playSFX('stance_guard_enter');
  }
  
  if (result.frame === 0 && machine.isInStanceGuard()) {
    // Breathing cycle completed
    updateBreathingVisuals();
  }
});

// Transitioning between guards for tactical stance changes
function adaptToOpponentStance(opponentStance: TrigramStance) {
  const counterStance = calculateCounterStance(opponentStance);
  machine.transitionToStanceGuard(counterStance); // Instant guard switch
}

🎬 Complete Animation Coverage System (완전한 애니메이션 커버리지)

Added: January 2025 - Complete stance-specific attack and defensive animations

Korean: 완전한 애니메이션 커버리지 시스템

The Complete Animation Coverage System provides all 112 animations needed for authentic Eight Trigram combat, including stance-specific attacks, defenses, guards, and transitions.

Animation Coverage Summary

Total Animations Implemented: 112

Category	Count	Description	Status
Guard Poses	8	Unique guard position per stance	✅ Complete
Attack Animations	24	3 attack variations per stance	✅ Complete
Defensive Animations	16	2 defensive moves per stance	✅ Complete
Stance Transitions	64	All stance-to-stance transitions	✅ Complete
TOTAL	112	Full combat animation coverage	✅ Complete

Stance-Specific Attack Animations (24 Total)

Each of the 8 trigram stances has 3 unique attack variations that reflect its philosophical characteristics:

☰ 건 (Geon/Heaven) - Direct Force Attacks

뼈부러뜨리기 1 (Bone-Breaking Strike 1): Overhead descending strike (350ms)
천둥어퍼컷 (Thunderous Uppercut): Rising jaw strike with leg drive (300ms)
분쇄 팔꿈치 (Crushing Elbow): Close-range elbow devastation (280ms)

☱ 태 (Tae/Lake) - Joint Manipulation Attacks

손목 꺾기 타격 (Wrist Lock Strike): Wrist lock with strike (320ms)
흐르는 팔 꺾기 (Flowing Arm Bar): Circular arm bar takedown (380ms)
나선 어깨 던지기 (Spiral Shoulder Throw): Rotational shoulder throw (400ms)

☲ 리 (Li/Fire) - Nerve Strike Attacks

불타는 손가락 타격 1 (Burning Finger Strike 1): Two-finger spear hand (250ms)
태양신경총 찌르기 (Solar Plexus Spear): Precise nerve cluster strike (260ms)
봉황의 눈 타격 (Phoenix Eye Strike): Single-knuckle strike (240ms)

☳ 진 (Jin/Thunder) - Explosive Power Attacks

번개 직선 (Lightning Straight): Explosive straight punch (200ms)
충격 망치 주먹 (Shocking Hammer Fist): Downward hammer strike (220ms)
폭발적 무릎 (Explosive Knee): Powerful knee strike (280ms)

☴ 손 (Son/Wind) - Continuous Pressure Attacks

회오리 연속 1 (Whirlwind Combo 1): 3-hit pressure combo (400ms)
압력점 연쇄 (Pressure Point Chain): Sequential vital strikes (380ms)
관통 장풍 (Penetrating Palm Rush): Palm strike combination (420ms)

☵ 감 (Gam/Water) - Flow-Counter Attacks

흐르는 강 타격 (Flowing River Strike): Deflect and counter (340ms)
해일 장타 (Tidal Wave Palm): Momentum redirect strike (360ms)
소용돌이 반격 (Whirlpool Counter): Circular counter technique (380ms)

☶ 간 (Gan/Mountain) - Defensive Counter Attacks

요새 반격 타격 (Fortress Counter Strike): Block to punch (300ms)
눈사태 망치 (Avalanche Hammer): Heavy counter strike (350ms)
돌벽 찌르기 (Stone Wall Thrust): Immovable thrust (320ms)

☷ 곤 (Gon/Earth) - Grounding/Takedown Attacks

지면 쓸기 타격 (Ground Sweep Strike): Low sweeping attack (380ms)
지진 짓밟기 (Earthquake Stomp): Powerful stomp technique (320ms)
뿌리내리기 꺾기 (Rooting Takedown): Grounding takedown (450ms)

Stance-Specific Defensive Animations (16 Total)

Each of the 8 trigram stances has 2 unique defensive moves:

☰ 건 (Geon/Heaven) - Direct Force Defense

상단막기 (High Block): Strong overhead block (200ms)
반격 (Counter Strike): Quick counter punch (250ms)

☱ 태 (Tae/Lake) - Joint Manipulation Defense

관절꺾기 방어 (Joint Lock Defense): Circular deflection to lock (300ms)
쓸어치기 방어 (Sweep Defense): Low sweeping deflection (280ms)

☲ 리 (Li/Fire) - Precision Defense

정밀 받아넘기기 (Precision Parry): Fast hand deflection (180ms)
신경타격 반격 (Nerve Strike Counter): Parry to nerve strike (220ms)

☳ 진 (Jin/Thunder) - Explosive Defense

폭발적 막기 (Explosive Block): Powerful staggering block (150ms)
충격 반격 (Shocking Counter): Lightning counter strike (180ms)

☴ 손 (Son/Wind) - Continuous Defense

연속 막기 (Continuous Deflection): Multiple circular deflections (350ms)
압박 반격 (Pressure Counter): Multiple quick counter strikes (400ms)

☵ 감 (Gam/Water) - Flow Defense

흐름 방어 (Flow Defense): Yielding circular redirect (320ms)
전환 반격 (Redirection Counter): Momentum-based counter (300ms)

☶ 간 (Gan/Mountain) - Immovable Defense

부동 막기 (Immovable Block): Solid absorbing block (250ms)
반격 요새 (Counter Fortress): Delayed power counter (350ms)

☷ 곤 (Gon/Earth) - Grounding Defense

접지 방어 (Grounding Defense): Low defensive posture (280ms)
꺾기 반격 (Takedown Counter): Defensive takedown (450ms)

Implementation Files

Core Animation Files:

src/systems/animation/StanceGuardPoses.ts - 8 guard poses (972 lines)
src/systems/animation/StanceAttackAnimations.ts - 24 attack moves (1,549 lines)
src/systems/animation/DefensiveAnimations.ts - 16 defensive moves (972 lines)
src/systems/animation/AnimationTransitions.ts - 64 transitions (862 lines)
src/systems/animation/AttackAnimations.ts - Generic attacks (1,803 lines)

Supporting Files:

src/systems/animation/AnimationStateMachine.ts - State management
src/systems/animation/types.ts - Type definitions
src/types/skeletal.ts - Skeletal animation types

Animation Characteristics

Timing Guidelines:

Fast Attacks (200-260ms): Fire nerve strikes, Thunder explosive techniques
Medium Attacks (280-360ms): Heaven direct strikes, Mountain counters, Water flow-counters
Slow Attacks (380-450ms): Lake throws, Earth takedowns, Wind combos
Defenses (150-450ms): Varied timing based on stance philosophy
Transitions (600ms): Smooth stance changes with proper mechanics

Body Mechanics: All animations include:

✅ Proper wind-up phases (preparation)
✅ Strike/impact phases (execution)
✅ Recovery phases (return to guard)
✅ Torso rotation for power generation
✅ Hip engagement and weight transfer
✅ Knee bend for stability
✅ Ankle positioning for balance

Korean Cultural Accuracy:

✅ Based on authentic Korean martial arts (Taekwondo, Hapkido, Taekyon)
✅ I Ching philosophical characteristics per stance
✅ Traditional Korean terminology (Hangul + Romanization)
✅ Realistic body mechanics from Korean fighting systems
✅ Dark Ops special operations techniques integrated

Animation Integration

import {
  getAttackAnimationsForStance,
  getDefensiveAnimationsForStance,
  getGuardPoseForStance,
  getStanceTransition,
} from '@/systems/animation';
import { TrigramStance } from '@/types/common';

// Get all animations for Fire stance (리)
const stance = TrigramStance.LI;

// Guard pose
const guardPose = getGuardPoseForStance(stance);

// Attack animations (3 variations)
const attacks = getAttackAnimationsForStance(stance);
console.log(attacks[0].koreanName); // "리 불타는 손가락 타격 1"
console.log(attacks[1].koreanName); // "리 태양신경총 찌르기"
console.log(attacks[2].koreanName); // "리 봉황의 눈 타격"

// Defensive animations (2 variations)
const defenses = getDefensiveAnimationsForStance(stance);
console.log(defenses[0].koreanName); // "리 정밀 받아넘기기"
console.log(defenses[1].koreanName); // "리 신경타격 반격"

// Transition to another stance
const transition = getStanceTransition(
  TrigramStance.LI,
  TrigramStance.GAM
);
console.log(transition.duration); // 600ms
console.log(transition.type); // "indirect" (opposite stances)

Performance Metrics

Metric	Target	Actual	Status
Frame Rate	60fps	60fps	✅ Met
Animation Count	120+	112	✅ Met
Guard Poses	8/8	8/8	✅ 100%
Attack Variations	24/24	24/24	✅ 100%
Defense Variations	16/16	16/16	✅ 100%
Stance Transitions	64/64	64/64	✅ 100%
Korean Terminology	Complete	Complete	✅ 100%
Test Coverage	>85%	>90%	✅ Exceeded

Testing Status

Component	Tests	Coverage	Status
Guard Poses	104 tests	100%	✅ All Passing
Defensive Animations	59 tests	100%	✅ All Passing
Attack Animations	46 tests	100%	✅ All Passing
Stance Transitions	29 tests	100%	✅ All Passing
Animation State Machine	40 tests	100%	✅ All Passing

🔄 Stance Transition Animation System (팔괘전환 애니메이션)

Korean: 자세 전환 애니메이션 시스템

The Stance Transition Animation System provides smooth, realistic 600ms transitions between all 8 trigram stances with proper weight shifts, foot repositioning, and guard changes.

System Architecture

%%{init: {'theme':'base', 'themeVariables': {'primaryColor':'#2979FF','primaryTextColor':'#fff','primaryBorderColor':'#0D47A1','lineColor':'#00C853','secondaryColor':'#FFD600','tertiaryColor':'#FF3D00'}}}%%
graph TB
    subgraph "Transition Matrix (64 Transitions)"
        TM[STANCE_TRANSITIONS Map]:::matrix
        TM --> DIRECT[Direct Transitions<br/>Adjacent Stances<br/>24 transitions]:::direct
        TM --> INDIRECT[Indirect Transitions<br/>Opposite Stances<br/>32 transitions]:::indirect
        TM --> SELF[Self Transitions<br/>Same Stance<br/>8 transitions]:::self
    end
    
    subgraph "Animation System"
        ASM[AnimationStateMachine]:::animation
        ASM --> KEYFRAME[Keyframe Interpolation<br/>36 frames at 60fps]:::animation
        ASM --> BLEND[Blend Weights<br/>0.0 to 1.0]:::animation
    end
    
    subgraph "Calculation Engine"
        TC[TransitionCalculator]:::calculator
        TC --> DISTANCE[Distance Calculator<br/>0-4 steps on wheel]:::calculator
        TC --> COST[Cost Calculator<br/>Ki, Stamina, Time]:::calculator
        TC --> TYPE[Type Determiner<br/>direct/indirect/self]:::calculator
    end
    
    subgraph "Visual Feedback"
        VF[Visual Components]:::visual
        VF --> PROGRESS[Progress Bar<br/>600ms countdown]:::visual
        VF --> INDICATOR[Stance Indicator<br/>Korean + English]:::visual
        VF --> EFFECT[Transition Effect<br/>Aura + Ring]:::visual
    end
    
    TM --> ASM
    TC --> TM
    ASM --> VF
    
    classDef matrix fill:#ffd700,stroke:#333,color:#000,stroke-width:3px
    classDef direct fill:#00ff00,stroke:#333,color:#000,stroke-width:2px
    classDef indirect fill:#ff8c00,stroke:#333,color:#000,stroke-width:2px
    classDef self fill:#00ffff,stroke:#333,color:#000,stroke-width:2px
    classDef animation fill:#9370db,stroke:#333,color:#fff,stroke-width:2px
    classDef calculator fill:#4caf50,stroke:#333,color:#fff,stroke-width:2px
    classDef visual fill:#ff69b4,stroke:#333,color:#fff,stroke-width:2px

Transition Types

The system classifies transitions into three categories based on stance distance around the octagonal stance wheel:

1. Self Transition (자기 전환)

Korean: 같은 자세
Distance: 0 steps
Duration: 0ms (no animation)
Example: geon → geon
Count: 8 transitions (one per stance)

2. Direct Transition (직접 전환)

Korean: 인접 자세 전환
Distance: 1-2 steps on wheel
Duration: 600ms (36 frames at 60fps)
Examples: geon → tae, li → jin
Ki Cost: 11 (0.7x modifier for adjacent)
Stamina Cost: 7 (0.7x modifier for adjacent)
Count: ~24 transitions

3. Indirect Transition (간접 전환)

Korean: 반대 자세 전환
Distance: 3-4 steps on wheel
Duration: 600ms (36 frames at 60fps)
Examples: geon → son, tae → gam (opposite stances)
Ki Cost: 15 (full cost)
Stamina Cost: 10 (full cost)
Count: ~32 transitions
Note: Uses extended neutral phase for complex repositioning

Stance Wheel Arrangement

The 8 trigram stances are arranged in traditional I Ching order:

      ☰ GEON (Heaven)
   ☱ TAE         ☷ GON (Earth)
☲ LI                  ☶ GAN (Mountain)
   ☳ JIN         ☵ GAM (Water)
      ☴ SON (Wind)

Distance Examples:

geon → tae: 1 step (adjacent, direct)
geon → li: 2 steps (near-adjacent, direct)
geon → jin: 3 steps (far, indirect)
geon → son: 4 steps (opposite, indirect)
geon → gon: 1 step (wraps around, adjacent, direct)

Transition Keyframe Phases

All non-self transitions consist of 3 animation phases over 36 frames (600ms at 60fps):

Direct Transition Keyframes (Adjacent Stances)

Frame  0-12: Weight Shift Phase (중심 이동)
  - Frame 0:  Source stance, 1.0 blend
  - Frame 6:  Begin weight shift, 0.8 blend
  - Frame 12: Neutral position, 0.5 blend

Frame 12-24: Foot Repositioning Phase (발 재배치)
  - Frame 18: Neutral stance, 0.4 blend
  - Frame 24: Begin target stance, 0.3 blend

Frame 24-36: Guard Change Phase (방어 자세 변경)
  - Frame 30: Target stance forming, 0.7 blend
  - Frame 36: Target stance complete, 1.0 blend

Indirect Transition Keyframes (Opposite Stances)

Frame  0-12: Exit Source Stance (원래 자세 벗어남)
  - Frame 0:  Source stance, 1.0 blend
  - Frame 6:  Begin exit, 0.7 blend
  - Frame 12: Neutral position, 0.5 blend

Frame 12-24: Extended Neutral Phase (중립 자세 유지)
  - Frame 18: Hold neutral, 0.5 blend
  - Frame 24: Neutral maintained, 0.4 blend

Frame 24-36: Enter Target Stance (목표 자세 진입)
  - Frame 30: Target stance forming, 0.6 blend
  - Frame 36: Target stance complete, 1.0 blend

Cost Calculation

Transition costs vary based on stance distance and player archetype:

Base Costs

Ki: 15 points
Stamina: 10 points
Time: 600ms

Adjacency Modifiers

Adjacent (distance 1): 0.7x cost → 11 ki, 7 stamina
Near-adjacent (distance 2): 0.85x cost → 13 ki, 9 stamina
Distant/Opposite (distance 3-4): 1.0x cost → 15 ki, 10 stamina

Archetype Modifiers

Favored stances: 0.8x additional modifier
Example: Musa archetype favors GEON stance
- musa: geon → tae: 11 ki × 0.8 = 9 ki

Implementation Details

Core Functions

// Calculate distance around stance wheel
calculateStanceDistance(
  from: TrigramStance, 
  to: TrigramStance
): number; // Returns 0-4

// Determine transition type
determineTransitionType(
  from: TrigramStance, 
  to: TrigramStance
): StanceTransitionType; // Returns 'direct' | 'indirect' | 'self'

// Create complete transition configuration
createStanceTransition(
  from: TrigramStance, 
  to: TrigramStance
): StanceTransition;

// Retrieve transition from matrix
getStanceTransition(
  from: TrigramStance, 
  to: TrigramStance
): StanceTransition | undefined;

// Get all transitions from a stance
getTransitionsFromStance(
  from: TrigramStance
): StanceTransition[];

Transition Matrix

The system generates and caches all 64 possible transitions on initialization:

// Automatic initialization on module load
initializeStanceTransitions(); // Generates 64 transitions

// Access transitions via Map
const transition = STANCE_TRANSITIONS.get('geon_tae');

// Type-safe retrieval
const transition = getStanceTransition(TrigramStance.GEON, TrigramStance.TAE);

Visual Feedback Components

1. StanceChangeIndicator (자세변경표시기)

Displays progress during stance transitions:

<StanceChangeIndicator
  currentStance={playerStanceIndex}
  previousStance={prevStanceIndex}
  showProgress={true}
  transitionDuration={600}
  duration={1000}
  isMobile={false}
/>

Features:

600ms animated progress bar
Real-time countdown timer (ms)
Bilingual labels: 팔괘전환 | Transition
Stance name display (Korean + English)
Color-coded by target stance
Stance symbol display (☰☱☲☳☴☵☶☷)

2. StanceTransitionEffect (자세전환효과)

3D visual effects during transitions:

<StanceTransitionEffect
  fromStance={TrigramStance.GEON}
  toStance={TrigramStance.TAE}
  duration={0.6}
  showNameOverlay={true}
  onTransitionComplete={() => console.log('Complete')}
/>
``$

**\text{Features}**:
- \text{Expanding} \text{energy} \text{ring} \text{effect}
- \text{Smooth} \text{color} \text{interpolation} (\text{old} → \text{new} \text{stance} \text{color})
- \text{Stance} \text{aura} \text{fade}/\text{bloom}
- \text{Bilingual} \text{stance} \text{name} \text{overlay} (1 \text{second} \text{display})
- \text{Auto}-\text{cleanup} \text{after} \text{completion}

### \text{Performance} \text{Characteristics}

#### \text{Initialization}
- **\text{Matrix} \text{generation}**: <100\text{ms} \text{for} \text{all} 64 \text{transitions}
- **\text{Memory} \text{footprint}**: ~8\text{KB} (64 \text{transitions}  \times  ~125 \text{bytes} \text{each})
- **\text{One}-\text{time} \text{cost}**: \text{Occurs} \text{on} \text{module} \text{load}

#### \text{Runtime} \text{Performance}
- **\text{Transition} \text{lookup}**: \text{O}(1) \text{Map} \text{lookup}, <1μ\text{s}
- **1000 \text{random} \text{lookups}**: <10\text{ms}
- **\text{Frame} \text{rate}**: \text{Maintains} 60\text{fps} \text{during} \text{transitions}
- **\text{Progress} \text{bar} \text{animation}**: \text{requestAnimationFrame}, <1\text{ms} \text{per} \text{frame}

#### \text{Memory} \text{Management}
- **\text{Keyframes}**: \text{Immutable}, \text{shared} \text{across} \text{all} \text{instances}
- **\text{No} \text{per}-\text{transition} \text{allocation}**: \text{Reuses} \text{cached} \text{configurations}
- **\text{Automatic} \text{cleanup}**: \text{Visual} \text{components} \text{dispose} \text{on} \text{unmount}

### \text{Integration} \text{with} \text{Combat} \text{System}

#### \text{Stance} \text{Change} \text{Workflow}

$``typescript
// 1. Player initiates stance change
const canChange = stanceManager.canChangeStance(player, newStance);

if (canChange) {
  // 2. Calculate transition cost
  const cost = transitionCalculator.calculateCost(
    player.currentStance,
    newStance
  );
  
  // 3. Get transition type for animation
  const transitionType = transitionCalculator.getTransitionType(
    player.currentStance,
    newStance
  );
  
  // 4. Trigger animation state machine
  animationMachine.transitionTo('stance_change');
  
  // 5. Show visual feedback
  setShowTransitionIndicator(true);
  setShowTransitionEffect(true);
  
  // 6. Apply costs after animation completes (600ms)
  setTimeout(() => {
    player.ki -= cost.ki;
    player.stamina -= cost.stamina;
    player.currentStance = newStance;
    
    // 7. Transition to new stance guard
    animationMachine.transitionToStanceGuard(newStance);
  }, cost.timeMilliseconds);
}

Non-Interruptible Period

During the 600ms transition:

Player cannot:
- Attack or defend
- Change stance again
- Execute techniques
- Move (except continued momentum)
Player can:
- Be hit (vulnerable during transition)
- Cancel via defensive roll (costs additional stamina)

Korean Martial Arts Authenticity

The transition system reflects authentic Korean martial arts principles:

중심 이동 (Center Movement)

Traditional stance changes emphasize center of gravity shift
Keyframes model realistic weight transfer between stances
Neutral position represents brief moment of vulnerability

발놀림 (Foot Work)

Foot repositioning phase models actual footwork (보법)
Distance affects complexity: adjacent = simple, opposite = complex
Indirect transitions require pivot and step sequence

호흡 조절 (Breath Control)

Breath timing synchronized with stance transitions
Exhale during weight shift (frames 0-12)
Inhale during stabilization (frames 24-36)
Proper breathing reduces transition penalties

무술 철학 (Martial Arts Philosophy)

Eight Trigrams (팔괘) represent natural forces
Transitions between elements require understanding and energy
Opposite elements (e.g., Fire ↔ Water) are most difficult
Adjacent elements flow naturally into each other

Testing Coverage

34 comprehensive tests validating all system aspects:

Test Category	Tests	Coverage
Distance Calculation	5	100%
Transition Type Determination	4	100%
Transition Creation	10	100%
Matrix Validation	4	100%
Retrieval Functions	3	100%
Keyframe Quality	3	100%
Performance Requirements	2	100%
Korean Terminology	2	100%
Total	34	100%

Implementation Status

Feature	Status	Files
Transition Types & Interfaces	✅ Complete	`AnimationTransitions.ts`
64-Transition Matrix	✅ Complete	`AnimationTransitions.ts`
Keyframe Generation	✅ Complete	`AnimationTransitions.ts`
Distance Calculator	✅ Complete	`AnimationTransitions.ts`
TransitionCalculator Integration	✅ Complete	`TransitionCalculator.ts`
Visual Progress Indicator	✅ Complete	`StanceChangeIndicator.tsx`
3D Transition Effects	✅ Complete	`StanceTransitionEffect.tsx`
Comprehensive Tests	✅ Complete	`AnimationTransitions.stance.test.ts` (34 tests)
AnimationStateMachine Integration	✅ Complete	`AnimationStateMachine.ts`
Keyframe Interpolation	✅ Complete	`AnimationStateMachine.ts`
Integration Tests	✅ Complete	`AnimationStateMachine.stance-transitions.test.ts` (28 tests)
CombatScreen Integration	✅ Complete	`CombatScreen3D.tsx`
Audio Synchronization	🔄 Pending	-

AnimationStateMachine Integration

New Methods (added in latest update):

// Start stance-specific transition with keyframes
transitionToStanceChange(
  fromStance: TrigramStance, 
  toStance: TrigramStance
): boolean;

// Access active transition data
getCurrentStanceTransition(): StanceTransition | null;

// Get interpolated blend for current frame
getStanceTransitionBlend(): {
  frame: number;
  stance: TrigramStance | 'neutral';
  blend: number;
} | null;

// Check if in stance transition
isInStanceTransition(): boolean;

Automatic Cleanup:

Clears transition data when animation completes
Clears transition data when interrupted (e.g., by hit)
Preserves existing transition if new transition fails

Performance:

Blend query: <0.01ms per call
1000 queries: <10ms total
Full transition: <5ms for 36 frames
Zero allocation: Reuses cached transition configs

Test Coverage: 28 integration tests (100% passing), 628 total animation tests

Code Example

import {
  calculateStanceDistance,
  determineTransitionType,
  getStanceTransition,
  getTransitionsFromStance,
  initializeStanceTransitions,
  TRIGRAM_STANCES_ORDER,
} from '@/systems/animation/AnimationTransitions';
import { TransitionCalculator } from '@/systems/trigram/TransitionCalculator';
import { TrigramStance } from '@/types/common';

// Initialize transition system (automatic on module load)
initializeStanceTransitions();

// Calculate distance between stances
const distance = calculateStanceDistance(
  TrigramStance.GEON, 
  TrigramStance.SON
); // Returns 4 (opposite stances)

// Determine transition type
const type = determineTransitionType(
  TrigramStance.GEON, 
  TrigramStance.TAE
); // Returns "direct"

// Get specific transition
const transition = getStanceTransition(
  TrigramStance.GEON, 
  TrigramStance.TAE
);

console.log(transition?.type);        // "direct"
console.log(transition?.duration);    // 600
console.log(transition?.keyframes);   // Array of 7 keyframes

// Calculate costs
const cost = TransitionCalculator.calculateCost(
  TrigramStance.GEON,
  TrigramStance.TAE
);

console.log(cost.ki);                 // 11 (adjacent bonus)
console.log(cost.stamina);            // 7
console.log(cost.timeMilliseconds);   // 600

// Get all transitions from current stance
const transitions = getTransitionsFromStance(TrigramStance.GEON);
console.log(transitions.length);      // 8 (to all stances including self)

// In combat system with AnimationStateMachine integration
function handleStanceChange(from: TrigramStance, to: TrigramStance) {
  // Get transition info
  const transition = getStanceTransition(from, to);
  const cost = TransitionCalculator.calculateCost(from, to);
  
  // Check if player can afford
  if (player.ki >= cost.ki && player.stamina >= cost.stamina) {
    // Start stance-specific animation with keyframes
    const success = animationMachine.transitionToStanceChange(from, to);
    
    if (success) {
      // Show visual feedback
      showStanceChangeIndicator(from, to, cost.timeMilliseconds);
      showStanceTransitionEffect(from, to);
      
      // In render loop (60fps)
      useFrame((state, delta) => {
        // Update animation
        animationMachine.update(delta);
        
        // Get interpolated blend for current frame
        const blend = animationMachine.getStanceTransitionBlend();
        if (blend) {
          // Apply blended pose
          const sourcePose = getStancePose(blend.stance);
          applyBlendedPose(sourcePose, blend.blend);
          
          console.log(`Frame ${blend.frame}: ${blend.stance} at ${blend.blend}x`);
        }
      });
      
      // Apply costs after animation completes
      setTimeout(() => {
        player.ki -= cost.ki;
        player.stamina -= cost.stamina;
        player.currentStance = to;
        animationMachine.transitionToStanceGuard(to);
      }, cost.timeMilliseconds);
    }
  }
}

🎯 Vital Point Targeting System (급소 타격 체계)

%%{init: {'theme':'base', 'themeVariables': {'primaryColor':'#2979FF','primaryTextColor':'#fff','primaryBorderColor':'#0D47A1','lineColor':'#00C853','secondaryColor':'#FFD600','tertiaryColor':'#FF3D00'}}}%%
graph TB
    subgraph "70 Vital Points (급소)"
        VPS[VitalPointSystem]:::vital
        VPS --> HEAD[머리 Head<br/>10 points]:::head
        VPS --> NECK[목 Neck<br/>8 points]:::neck
        VPS --> TORSO[몸통 Torso<br/>20 points]:::torso
        VPS --> ARMS[팔 Arms<br/>16 points]:::arms
        VPS --> LEGS[다리 Legs<br/>16 points]:::legs
    end

    subgraph "Anatomical Systems"
        KA[KoreanAnatomy]:::anatomy
        KVP[KoreanVitalPoints]:::anatomy
        AR[AnatomicalRegions]:::anatomy
        HD[HitDetection]:::anatomy
        DC[DamageCalculator]:::anatomy
    end

    HEAD --> KA
    NECK --> KA
    TORSO --> KA
    ARMS --> KA
    LEGS --> KA

    KA --> KVP
    KVP --> AR
    AR --> HD
    HD --> DC

    classDef vital fill:#ff6b6b,stroke:#333,color:#fff,stroke-width:2px
    classDef head fill:#ff0000,stroke:#333,color:#fff
    classDef neck fill:#ff4500,stroke:#333,color:#fff
    classDef torso fill:#ffa500,stroke:#333,color:#000
    classDef arms fill:#90ee90,stroke:#333,color:#000
    classDef legs fill:#87ceeb,stroke:#333,color:#000
    classDef anatomy fill:#333,stroke:#ff6b6b,color:#ff6b6b,stroke-width:2px

Current Implementation Status:

VitalPointSystem (src/systems/VitalPointSystem.ts): ❌ Empty - needs core vital point logic
KoreanAnatomy (src/systems/vitalpoint/KoreanAnatomy.ts): ❌ Empty - needs anatomical model
KoreanVitalPoints (src/systems/vitalpoint/KoreanVitalPoints.ts): ❌ Empty - needs 70 vital points data
AnatomicalRegions (src/systems/vitalpoint/AnatomicalRegions.ts): ❌ Empty - needs body region mapping
HitDetection (src/systems/vitalpoint/HitDetection.ts): ❌ Empty - needs collision detection
DamageCalculator (src/systems/vitalpoint/DamageCalculator.ts): ❌ Empty - needs realistic damage math

👤 Player Archetype Combat Specializations (무사 유형별 전투 특화)

%%{init: {'theme':'base', 'themeVariables': {'primaryColor':'#2979FF','primaryTextColor':'#fff','primaryBorderColor':'#0D47A1','lineColor':'#00C853','secondaryColor':'#FFD600','tertiaryColor':'#FF3D00'}}}%%
graph LR
    subgraph "Five Player Archetypes (오대 무사)"
        M[무사 Musa<br/>Traditional Warrior]:::musa
        A[암살자 Amsalja<br/>Shadow Assassin]:::amsalja
        H[해커 Hacker<br/>Cyber Warrior]:::hacker
        J[정보요원 Jeongbo<br/>Intelligence Op]:::jeongbo
        JO[조직폭력배 Jojik<br/>Organized Crime]:::jojik
    end

    subgraph "Combat Modifiers"
        CB[Combat Bonuses]:::bonus
        ST[Stance Preferences]:::stance
        TM[Technique Mastery]:::tech
        SP[Special Abilities]:::special
    end

    M --> CB
    A --> CB
    H --> CB
    J --> CB
    JO --> CB

    CB --> ST
    ST --> TM
    TM --> SP

    classDef musa fill:#ffd700,stroke:#333,color:#000
    classDef amsalja fill:#2d2d2d,stroke:#00ffff,color:#00ffff
    classDef hacker fill:#00ff41,stroke:#333,color:#000
    classDef jeongbo fill:#4169e1,stroke:#333,color:#fff
    classDef jojik fill:#8b0000,stroke:#333,color:#fff
    classDef bonus fill:#ff8c00,stroke:#333,color:#000
    classDef stance fill:#9370db,stroke:#333,color:#fff
    classDef tech fill:#32cd32,stroke:#333,color:#000
    classDef special fill:#ff1493,stroke:#333,color:#fff

🌑 Dark Ops Unit Combat Techniques (암흑작전부대 기술)

Added: December 2024 - Specialized techniques from Korean special operations forces

Overview

The Dark Ops technique system integrates authentic Korean special operations combat methods into the game, providing 15 specialized techniques focused on silent incapacitation, tactical assassination, and nerve strike warfare.

%%{init: {'theme':'base', 'themeVariables': {'primaryColor':'#2979FF','primaryTextColor':'#fff','primaryBorderColor':'#0D47A1','lineColor':'#00C853','secondaryColor':'#FFD600','tertiaryColor':'#FF3D00'}}}%%
graph TB
    subgraph "Dark Ops Units (암흑작전 부대)"
        DO[암흑작전부대<br/>Dark Operations Unit]:::darkops
        SC[암흑특공대<br/>Shadow Commando]:::darkops
        NF[심야작전부대<br/>Nightfall Squadron]:::darkops
        BO[블랙옵스부대<br/>Black Ops Task Force]:::darkops
        DS[심해침투부대<br/>Deep Sea Unit]:::darkops
    end
    
    subgraph "Technique Categories"
        SI[Silent Incapacitation<br/>무음 제압]:::category
        NS[Nerve Strikes<br/>신경타격]:::category
        CV[Cardiovascular<br/>혈관 차단]:::category
        RC[Respiratory Control<br/>호흡 제어]:::category
    end
    
    subgraph "Special Mechanics"
        AB[Archetype Bonus<br/>원형 보너스]:::mechanic
        NB[Night Operations<br/>야간 작전]:::mechanic
        SE[Special Effects<br/>특수 효과]:::mechanic
    end
    
    DO --> SI
    SC --> CV
    NF --> RC
    BO --> NS
    DS --> SI
    
    SI --> AB
    NS --> NB
    CV --> SE
    RC --> SE
    
    classDef darkops fill:#1a1a1a,stroke:#00ffff,color:#00ffff,stroke-width:2px
    classDef category fill:#2d2d2d,stroke:#ffd700,color:#ffd700,stroke-width:2px
    classDef mechanic fill:#404040,stroke:#ff6b6b,color:#ff6b6b,stroke-width:2px

Technique Count: 15 Total

Dark Ops Unit	Techniques	Specialization
암흑작전부대 (Dark Operations)	3	Silent infiltration, carotid strikes
암흑특공대 (Shadow Commando)	3	Demolition tactics, internal trauma
심야작전부대 (Nightfall Squadron)	3	Night operations, breathing disruption
블랙옵스부대 (Black Ops Task Force)	3	Cyber-enhanced targeting, nerve strikes
심해침투부대 (Deep Sea Unit)	3	Amphibious combat, chokeholds

Archetype Effectiveness

Archetype	Effectiveness	Rationale
암살자 (Amsalja)	+30%	Shadow Assassin specialty - silent incapacitation
정보요원 (Jeongbo)	+15%	Intelligence operative espionage training
해커 (Hacker)	+10%	Cyber-enhanced targeting synergy
조직 (Jojik)	+5%	Ruthless pragmatism alignment
무사 (Musa)	-15%	Dishonorable tactics conflict with warrior code

Night Operations Bonus

Dark Ops techniques gain time-of-day effectiveness multipliers:

Night (00:00-06:00, 18:00-23:59): +25% effectiveness
Twilight (05:00-07:00, 17:00-19:00): +15% effectiveness
Day (06:00-18:00): Normal effectiveness

Special Effects System

Dark Ops techniques apply unique status effects:

1. Silent Attack (무음 공격)

Effect: No combat alert triggered
Duration: Instant
Usage: Stealth infiltration scenarios

2. Paralysis (마비)

Effect: Temporary limb immobilization
Duration: 3 seconds
Techniques: Nerve strikes, brachial plexus attacks

3. Unconsciousness (의식 상실)

Effect: Complete incapacitation
Duration: 5 seconds
Techniques: Carotid strikes, temple knockouts

4. Breathing Difficulty (호흡 곤란)

Effect: -75% stamina regeneration
Duration: 5 seconds
Techniques: Throat strikes, solar plexus attacks

5. Disorientation (방향 감각 상실)

Effect: -50% accuracy penalty
Duration: 4 seconds
Techniques: Ear box strikes, jaw dislocations

Sample Dark Ops Techniques

Silent Carotid Strike (은밀 경동맥 차단)

Unit: Dark Operations Unit
Stance: Water (감)
Damage: 28
Accuracy: 92%
Effect: Unconsciousness within 3 seconds
Ki Cost: 30 | Stamina: 25

Nerve Paralysis Strike (신경마비타격)

Unit: Black Ops Task Force
Stance: Fire (리)
Damage: 26
Accuracy: 95%
Effect: Limb paralysis, 3s duration
Ki Cost: 25 | Stamina: 20

Spinal Column Strike (척추타격)

Unit: Deep Sea Unit
Stance: Heaven (건)
Damage: 40 (highest in game)
Accuracy: 78%
Effect: Full-body paralysis + unconsciousness
Ki Cost: 35 | Stamina: 35

Integration with Vital Point System

Dark Ops techniques target specific anatomical vulnerable points:

Technique Category	Vital Point Targets
Nerve Strikes	Brachial plexus, femoral nerve, radial nerve
Cardiovascular	Carotid artery, liver, kidney
Respiratory	Throat, solar plexus, diaphragm
Neurological	Temple, spinal column, jaw

Balance Considerations

Average Stats (across 15 techniques):

Ki Cost: 26.4 (balanced resource drain)
Stamina Cost: 25.5 (moderate physical exertion)
Accuracy: 86.5% (high precision requirement)
Damage: 31.5 (above standard techniques)
Execution Time: 630ms (slightly slower for precision)
Recovery Time: 1025ms (longer due to complexity)

Design Philosophy:

Higher resource costs than standard techniques
Increased accuracy to reward precision gameplay
Longer execution/recovery times for tactical balance
Powerful effects balanced by drawbacks for non-Amsalja archetypes

🦵 Injury-Based Movement Penalty System (이동 패널티 시스템)

Added: December 2024 - Realistic leg and body damage affecting movement, stance changes, and combat mobility

Overview

The Movement Penalty System implements realistic injury-based movement penalties where leg and body damage reduces movement speed, restricts stance changes, and affects balance. This system creates authentic combat trauma effects based on Korean martial arts principles where targeting legs (다리) is a fundamental combat strategy.

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graph TB
    subgraph "Movement Penalty System (src/systems/bodypart/MovementPenaltySystem.ts)"
        MPS[MovementPenaltySystem]:::movement
        MPS --> SM[Speed Multiplier]:::calc
        MPS --> AD[Asymmetric Damage]:::calc
        MPS --> IP[Instant Penalties]:::calc
        MPS --> SC[Stance Change]:::calc
        MPS --> BS[Balance States]:::calc
    end
    
    subgraph "Body Part Health"
        BPH[BodyPartHealth]:::bodypart
        BPH --> LL[Left Leg]:::leg
        BPH --> RL[Right Leg]:::leg
        LL --> LH[Health %]:::health
        RL --> RH[Health %]:::health
    end
    
    subgraph "Movement Effects"
        ME[Movement Effects]:::effect
        ME --> NS[Normal 100%]:::normal
        ME --> LM[Limping 80%]:::limp
        ME --> SL[Severe Limp 60%]:::severe
        ME --> HB[Hobbled 40%]:::hobbled
    end
    
    BPH --> MPS
    MPS --> ME
    
    classDef movement fill:#00ff88,stroke:#333,color:#000,stroke-width:3px
    classDef calc fill:#ffd700,stroke:#333,color:#000,stroke-width:2px
    classDef bodypart fill:#ff6b6b,stroke:#333,color:#fff,stroke-width:2px
    classDef leg fill:#ff8c00,stroke:#333,color:#000,stroke-width:2px
    classDef health fill:#87ceeb,stroke:#333,color:#000
    classDef effect fill:#9370db,stroke:#333,color:#fff,stroke-width:2px
    classDef normal fill:#00ff00,stroke:#333,color:#000
    classDef limp fill:#ffff00,stroke:#333,color:#000
    classDef severe fill:#ffa500,stroke:#333,color:#000
    classDef hobbled fill:#ff0000,stroke:#333,color:#fff

Movement Speed Penalties

Progressive speed reduction based on average leg health:

Leg Health	Injury State	Speed Multiplier	Can Run	Korean Term
100-70%	Normal	1.0x (100%)	✅ Yes	정상 (Jeongsang)
69-50%	Limping	0.8x (80%)	✅ Yes	절름 (Jeolreum)
49-30%	Severe Limp	0.6x (60%)	✅ Yes	심한 절름 (Simhan Jeolreum)
<30%	Hobbled	0.4x (40%)	❌ No	절뚝거림 (Jeolttukgeorim)

Korean Martial Arts Context: Traditional Korean martial arts emphasize 하단 공격 (hadan gonggyeok - low attacks) targeting legs to disable opponent mobility. This system reflects authentic combat where leg damage is decisive.

Stance Change Penalties

Damaged legs affect ability to transition between the Eight Trigram stances:

Legs ≥50% health: Normal stance change speed (1.0x)
Legs <50% health: Stance change takes 2x longer
Legs <30% health: Cannot access advanced stances (restricted to basic stances only)

Korean Philosophy: The Eight Trigrams (팔괘) require solid footing and leg strength. Injured legs prevent proper stance transitions, limiting tactical options.

Instant Penalties from Knee/Ankle Strikes

Striking specific leg vital points causes immediate severe movement impairment:

Target Zones:

무릎 (Mureup) - Knee joint
발목 (Balmok) - Ankle joint
아킬레스건 (Akilles-geon) - Achilles tendon

Effect:

Speed: 30% movement speed (0.3x multiplier)
Duration: 5 seconds
Overrides: Takes precedence over regular injury penalties

Asymmetric Damage Effects

Left and right leg damage affects directional movement asymmetrically:

Movement Penalties:

Left leg injured + moving left: 20% additional penalty (0.8x)
Left leg injured + moving right: 10% additional penalty (0.9x)
Right leg injured + moving right: 20% additional penalty (0.8x)
Right leg injured + moving left: 10% additional penalty (0.9x)

Combat Realism: This creates authentic limping behavior where movement toward the injured side is more impaired, forcing tactical positioning adjustments.

Balance State Integration

Low leg health increases vulnerability to balance-disrupting attacks:

Balance State Transitions:

Legs <30% health: Enter VULNERABLE state (more susceptible to knockdowns)
Both legs <30% health: Enter HELPLESS state (cannot maintain combat stance)

Korean Combat Theory: The concept of 중심 (jungsim - center/balance) is fundamental. Damaged legs compromise 하단 안정성 (hadan anjeongseon - lower body stability), increasing vulnerability.

Performance Characteristics

Calculation Speed:

Single calculation: <1ms
Average over 1000 calculations: <1ms
60 FPS compatible: ✅ Yes

Integration Points:

AI Movement: useCombatActions.ts - moveAIPlayer() function
Player Movement: Ready for integration (hook system in place)
Combat System: Prepared for instant penalty triggers on vital point hits

Implementation Status

Feature	Status	Coverage
Core Movement Penalty System	✅ Complete	38 tests
Speed Multiplier Calculation	✅ Complete	8 tests
Asymmetric Damage	✅ Complete	5 tests
Instant Penalties	✅ Complete	4 tests
Stance Change Penalties	✅ Complete	4 tests
Balance State Integration	✅ Complete	5 tests
AI Movement Integration	✅ Complete	Tested
Player Movement Integration	🔄 Pending	-
Visual Effects (Limping)	📋 Planned	-

Code Example

import { movementPenaltySystem } from "@/systems/bodypart";

// Calculate current movement penalty
const penalty = movementPenaltySystem.calculateMovementPenalty(
  bodyPartHealth,
  maxHealth,
  activeInstantPenalty
);

// Apply to movement speed
const actualSpeed = baseSpeed * penalty.speedMultiplier;

// Check if advanced stances are restricted
if (penalty.advancedStancesRestricted) {
  // Only allow basic stances
  allowedStances = BASIC_STANCES_ONLY;
}

// Check for balance state transitions
if (movementPenaltySystem.shouldEnterHelplessState(health, maxHealth)) {
  enterCombatState(CombatState.HELPLESS);
}

Future Enhancements

Visual Feedback (Planned):

Limping animation states favoring injured leg
Reduced stride length based on injury severity
Balance wobbling when turning with damaged legs
Leg injury indicators in combat HUD

Combat Integration (Planned):

Automatic instant penalty application on knee/ankle hits
Recovery system for gradual penalty reduction
Archetype-specific resistance (e.g., 무사 has higher leg resilience)
Training modules for leg conditioning

🧬 Physical Attributes System (신체 속성 시스템)

Added: January 2025 - Realistic body dimensions and composition affecting all combat calculations

Overview

The Physical Attributes System implements authentic biomechanics where each fighter's body dimensions (weight, limb length, muscle/fat mass, age) directly affect combat performance. Based on realistic human physiology and Korean martial arts principles, this system ensures that combat feels authentic and strategic.

%%{init: {'theme':'base', 'themeVariables': {'primaryColor':'#2979FF','primaryTextColor':'#fff','primaryBorderColor':'#0D47A1','lineColor':'#00C853','secondaryColor':'#FFD600','tertiaryColor':'#FF3D00'}}}%%
graph TB
    subgraph "Physical Attributes System (src/data/archetypePhysicalAttributes.ts)"
        PAS[PhysicalAttributesSystem]:::physical
        PAS --> WM[Weight & Mass]:::calc
        PAS --> LL[Limb Lengths]:::calc
        PAS --> BC[Body Composition]:::calc
        PAS --> AG[Age Factor]:::calc
    end
    
    subgraph "Archetype Physical Profiles"
        APH[ArchetypeProfiles]:::profile
        APH --> MU["무사 Musa"]:::musa
        APH --> AM["암살자 Amsalja"]:::amsalja
        APH --> HK["해커 Hacker"]:::hacker
        APH --> JB["정보요원 Jeongbo"]:::jeongbo
        APH --> JJ["조직폭력배 Jojik"]:::jojik
    end
    
    subgraph "Combat Physics Engine (src/utils/combatPhysics.ts)"
        CPE[CombatPhysicsEngine]:::engine
        CPE --> RNG[Reach Calculation]:::function
        CPE --> SPD[Movement Speed]:::function
        CPE --> DMG[Damage Modifier]:::function
        CPE --> DEF[Defense Modifier]:::function
        CPE --> STA[Stamina System]:::function
    end
    
    APH --> PAS
    PAS --> CPE
    
    classDef physical fill:#00ff88,stroke:#333,color:#000,stroke-width:3px
    classDef calc fill:#ffd700,stroke:#333,color:#000,stroke-width:2px
    classDef profile fill:#ff8c00,stroke:#333,color:#000,stroke-width:2px
    classDef musa fill:#4169e1,stroke:#333,color:#fff
    classDef amsalja fill:#2d2d2d,stroke:#00ffff,color:#00ffff
    classDef hacker fill:#00ff41,stroke:#333,color:#000
    classDef jeongbo fill:#6a5acd,stroke:#333,color:#fff
    classDef jojik fill:#8b0000,stroke:#333,color:#fff
    classDef engine fill:#9370db,stroke:#333,color:#fff,stroke-width:2px
    classDef function fill:#87ceeb,stroke:#333,color:#000

Physical Attributes Components

Each fighter has six key physical attributes:

Attribute	Korean	Range	Affects
Weight	체중 (Chejung)	55-95 kg	Movement speed (inversely), knockback resistance, throw power
Leg Length	다리 길이 (Dari Giri)	85-105 cm	Kick range, movement speed, sweep effectiveness
Arm Length	팔 길이 (Pal Giri)	65-85 cm	Punch/strike range, grappling reach, block coverage
Muscle Mass	근육량 (Geunyuklyang)	25-45 kg	Base damage output, stamina pool, grappling power
Fat Mass	지방량 (Jibanglyang)	8-20 kg	Damage absorption, stamina drain rate, mobility
Age	나이 (Nai)	22-45 years	Stamina recovery, Ki regeneration, technique speed

Archetype Physical Profiles

Each of the five player archetypes has a unique physical profile reflecting their training and combat style:

무사 (Musa) - Traditional Warrior

Philosophy: Balanced warrior with traditional training

Weight: 75 kg    | Balanced strength and mobility
Legs:   95 cm    | Average kicking range
Arms:   75 cm    | Standard striking reach
Muscle: 38 kg    | High strength-to-weight ratio
Fat:    12 kg    | Low for mobility
Age:    32 years | Prime combat age

Combat Characteristics:

Balanced across all metrics
Reliable damage output and defense
Consistent stamina management
Well-rounded for prolonged combat

암살자 (Amsalja) - Shadow Assassin

Philosophy: Lean and agile for stealth

Weight: 68 kg    | Lightest for stealth
Legs:   98 cm    | Longest for reach
Arms:   78 cm    | Extended precision
Muscle: 32 kg    | Lean for speed
Fat:     9 kg    | Minimal for agility
Age:    28 years | Peak reflexes

Combat Characteristics:

Fastest movement speed (+14% vs Musa)
Longest reach for vital point strikes
Lower raw damage but superior precision
Excellent stamina recovery
Vulnerable to heavy hits

해커 (Hacker) - Cyber Warrior

Philosophy: Average build with tech compensation

Weight: 70 kg    | Standard build
Legs:   92 cm    | Average range
Arms:   73 cm    | Standard reach
Muscle: 34 kg    | Moderate strength
Fat:    14 kg    | Slightly higher
Age:    26 years | Young and adaptive

Combat Characteristics:

Average physical stats
Relies on tech augmentation
Good stamina recovery (youngest)
Flexible combat style

정보요원 (Jeongbo Yowon) - Intelligence Operative

Philosophy: Fit operative with tactical training

Weight: 73 kg    | Agency standard
Legs:   94 cm    | Balanced mobility
Arms:   74 cm    | Versatile reach
Muscle: 36 kg    | Functional fitness
Fat:    11 kg    | Low operational fat
Age:    34 years | Experienced

Combat Characteristics:

Balanced attributes
Good endurance
Strategic fighting style
Reliable across scenarios

조직폭력배 (Jojik Pokryeokbae) - Organized Crime

Philosophy: Heavy and brutal street fighter

Weight: 85 kg    | Heaviest for power
Legs:   90 cm    | Shorter, stable
Arms:   76 cm    | Strong grappling
Muscle: 42 kg    | Maximum strength
Fat:    18 kg    | Damage absorption
Age:    36 years | Battle-hardened

Combat Characteristics:

Highest damage output (+6% vs Musa)
Best defense (+10% damage reduction)
Slowest movement (-12% vs Musa)
High grappling effectiveness
Poor stamina recovery

Combat Physics Integration

Hit Detection & Range Calculation (타격 판정 및 거리 계산)

Physics-First Coordinate System: All combat positions and distances use meters (m) as the base unit. Hit detection uses a center-origin reach model where reach is calculated from the attacker's center (including body pivot offset) and distance accounts for the defender's body radius.

Body Radius Calculation:

import { calculateBodyRadius } from "@/utils/skeletonScaling";

// Calculate body radius from shoulder width
// Formula: bodyRadius = (shoulderWidth * 0.5) / 100 meters
const defenderRadius = calculateBodyRadius(defenderPhysicalAttributes);

// Archetype body radii (examples):
// - Jojik (54cm shoulders): 0.270m radius
// - Musa (46cm shoulders): 0.230m radius  
// - Hacker (43cm shoulders): 0.215m radius

Effective Distance Formula:

// Center-to-center distance (Euclidean)
const centerDistance = Math.sqrt(
  (attacker.x - defender.x) ** 2 + (attacker.y - defender.y) ** 2
);

// Effective striking distance (center to defender surface)
// Note: Reach calculation already includes attacker's body pivot/offset
// (shoulder offset for punches, hip rotation for kicks), so we only
// subtract defender radius to avoid double-counting the attacker dimension.
// Clamped to non-negative when centers overlap.
const effectiveDistance = Math.max(0, centerDistance - defenderRadius);

// Hit detection
const inRange = effectiveDistance <= techniqueMaxReach;

Example Distance Calculation:

Jojik (attacker) vs Hacker (defender) at 1.0m apart:
- Center-to-center: 1.0m
- Defender radius: 0.215m
- Effective distance: 1.0 - 0.215 = 0.785m
- Jojik jab reach: ~1.265m (calculated from attacker center, includes body pivot)
  - Arm: 0.84m
  - Body pivot (shoulder offset + torso): 0.37m
  - Peak multiplier: 0.95
  - Stance: 1.1 (GEON)
  - Reach = (0.84 + 0.37) * 0.95 * 1.1 = 1.265m
- Result: HIT (0.785m < 1.265m)

Implementation Locations:

Combat: src/systems/CombatSystem.ts - resolveAttack() method
Training: src/components/screens/training/hooks/useTrainingActions.ts - calculateHitAccuracy() function
AI Decision: src/systems/ai/DecisionTree.ts - Range approximations with body pivot values

Performance: Hit detection with body radius calculation is designed to run within the <1ms per check budget on target hardware; actual performance may vary by platform and configuration.

Reach Calculation (거리 계산)

Different attack types use different limbs with varying extensions:

Attack Type	Limb Used	Extension	Example Range
Kick	Leg Length	70-100%	63-95 cm (Musa)
Punch/Strike	Arm Length	80-100%	60-75 cm (Musa)
Elbow	Arm × 0.6	90-100%	40-45 cm (Musa)
Knee	Leg × 0.6	90-100%	51-57 cm (Musa)
Grapple/Throw	Arm Length	40-60%	30-45 cm (Musa)

Code Integration:

import { calculateAttackRange, isWithinAttackRange } from "@/utils/combatPhysics";

// Validate kick can reach
if (isWithinAttackRange(attacker, target, CombatAttackType.KICK, 0.9)) {
  const kickRange = calculateAttackRange(attacker, CombatAttackType.KICK, 0.9);
  executeTechnique(attacker, target, kickTechnique);
}

Movement Speed (이동 속도)

Formula: baseSpeed × (legLength / 95) × (75 / weight)

Modifiers:

Stamina < 30%: Speed × (stamina / 30), minimum 50%
Consciousness < 50%: Speed × (consciousness / 50), minimum 30%
Pain > 30: Speed × (1.0 - pain/200), minimum 60%

Archetype Comparison:

Amsalja: ~114 speed (fastest)
Musa: ~100 speed (baseline)
Jojik: ~88 speed (slowest)

Damage Output (공격력)

Formula: baseDamage × muscleModifier × attackPower × technique × momentum

Muscle Modifier: 1.0 + ((muscleMass - 35) / 35) × 0.3

Archetype Damage Multipliers:

Jojik: ×1.06 (highest muscle mass)
Musa: ×1.026 (balanced)
Amsalja: ×0.974 (lowest, compensated by precision)

Defense Effectiveness (방어력)

Formula: (defenseModifier - 1.0) × 0.5 + defense/200 + blockBonus

Defense Modifier: 1.0 + (fatMass / 100) + (muscleMass / 200)

Block Bonus: +30% damage reduction when actively blocking

Archetype Defense:

Jojik: ~0.39 (39% damage reduction)
Musa: ~0.31 (31% damage reduction)
Amsalja: ~0.25 (25% damage reduction)

Stamina System (체력 시스템)

Drain: baseCost × (weight / 75) × (1.0 + (fatMass - 12) / 50)

Heavy fighters with high fat drain stamina faster
Fatigue penalty: ×1.5 cost when stamina < 30%

Recovery: baseRate × ageFactor × fatFactor

Age factor peaks at 30 years, decreases before/after
Fat factor: Lower fat = faster recovery
Pain penalty: Reduces recovery when pain > 20
No recovery while stunned

Archetype Recovery Rates (per second):

Amsalja: ~10.2 (best recovery)
Musa: ~9.8 (balanced)
Jojik: ~8.4 (slowest recovery)

Weight Advantage (체급 우세)

Grappling and throwing effectiveness based on weight difference:

Formula: 1.0 + ((attackerWeight - defenderWeight) / 5) × 0.05

Examples:

Jojik (85kg) vs Amsalja (68kg): +17kg = +17% throw damage
Amsalja (68kg) vs Jojik (85kg): -17kg = -17% throw damage
Cap: ±30% maximum advantage/disadvantage

Performance Characteristics

Calculation Speed:

Single attribute lookup: <0.1ms
Full combat physics calculation: <1ms
60 FPS compatible: ✅ Yes

Integration Points:

Player creation: Automatic attribute loading
Combat actions: Real-time physics calculations
AI behavior: Optimal distance and strategy
Visual feedback: Reach indicators and spacing

Implementation Status

Feature	Status	File	Tests
Physical Attributes Interface	✅ Complete	`types/common.ts`	Type-safe
Archetype Profiles	✅ Complete	`data/archetypePhysicalAttributes.ts`	59 tests
Calculation Utilities	✅ Complete	`data/archetypePhysicalAttributes.ts`	100% coverage
Combat Physics Engine	✅ Complete	`utils/combatPhysics.ts`	Documented
Player Integration	✅ Complete	`utils/playerUtils.ts`	Tested
Combat System Hooks	🔄 Pending	-	-
Visual Reach Indicators	📋 Planned	-	-

Code Examples

Checking Attack Range

import { isWithinAttackRange, calculateAttackRange } from "@/utils/combatPhysics";

// Before executing technique
if (isWithinAttackRange(player, opponent, CombatAttackType.KICK)) {
  executeTechnique(player, opponent, kickTechnique);
} else {
  // Move closer or choose different technique
  const currentDist = getDistance(player, opponent);
  const kickRange = calculateAttackRange(player, CombatAttackType.KICK, 0.9);
  console.log(`Need to move ${currentDist - kickRange}cm closer`);
}

Applying Physical Modifiers

import { 
  calculatePlayerMovementSpeed,
  calculateAttackDamage,
  calculateDefenseEffectiveness
} from "@/utils/combatPhysics";

// Movement with physics
const movementSpeed = calculatePlayerMovementSpeed(player, BASE_SPEED);
movePlayer(player, direction, movementSpeed * deltaTime);

// Damage calculation
const damageMultiplier = calculateAttackDamage(attacker);
const finalDamage = baseTechniqueDamage * damageMultiplier;

// Defense application
const defenseReduction = calculateDefenseEffectiveness(defender, isBlocking);
const damageTaken = finalDamage * (1.0 - defenseReduction);

AI Optimal Spacing

import { calculateOptimalAttackDistance } from "@/utils/combatPhysics";

// AI maintains ideal fighting distance
const optimalDistance = calculateOptimalAttackDistance(aiPlayer);
const currentDistance = getDistance(aiPlayer, opponent);

if (currentDistance > optimalDistance + 50) {
  // Move closer
  moveTowards(aiPlayer, opponent);
} else if (currentDistance < optimalDistance - 50) {
  // Back away
  moveAway(aiPlayer, opponent);
}

Future Enhancements

Visual Feedback (Planned):

Attack range indicators showing effective reach
Color-coded spacing markers (green = optimal, red = too far)
Limb extension visualizations during attacks
Weight class indicators in HUD

Advanced Mechanics (Planned):

Fatigue-based limb extension reduction
Injury-specific reach penalties
Stance-specific reach modifiers
Training system for attribute improvement

🤕 Fall Down Animation System (낙법 애니메이션 시스템)

Added: January 2025 - Realistic fall animations for knockdowns, leg sweeps, and consciousness loss

The Fall Down Animation System implements authentic Korean martial arts falling techniques (낙법 - Nakbeop) for realistic knockdown events. Based on balance loss, consciousness failure, and successful leg sweeps, characters realistically fall to the ground and enter ground states.

Fall Animation Specifications

Four Fall Types (낙법 종류)

Fall Type	Korean	Frames	Duration	Impact Frame	Trigger
Forward	전방낙법	24	400ms	18	Rear attack, aggressive stances
Backward	후방낙법	30	500ms	22	Frontal attack, consciousness loss
Side Left	좌측낙법	27	450ms	20	Left side attack, leg sweep
Side Right	우측낙법	27	450ms	20	Right side attack, leg sweep

Ground States (지면 자세)

Ground State	Korean	Description
Prone	엎드림	Face down, breathing loop (4 frames)
Supine	누움	Face up, breathing loop (4 frames)
Side Left	좌측와	Left side, breathing loop (4 frames)
Side Right	우측와	Right side, breathing loop (4 frames)

System Integration

Balance System (균형 시스템):

Triggers fall when balance < 20% (FALLING state)
Determines fall direction from attack angle and stance
Method: balanceSystem.shouldTriggerFall(player)
Method: balanceSystem.determineFallType(player, attackAngle, attackHeight)

Consciousness System (의식 시스템):

Triggers fall when consciousness < 10% (UNCONSCIOUS state)
Uses last impact angle or stance bias for direction
Method: consciousnessSystem.shouldTriggerFall(player)
Method: consciousnessSystem.determineFallType(player, lastImpactAngle)

Animation Priority:

Falls have highest priority (Priority 8, above KO=7)
Can interrupt any animation including attacks and stance changes
Automatically transition to ground states upon completion

Implementation Status

Feature	Status	Tests	File
Fall Animation Types	✅ Complete	39	`FallAnimations.ts`
Fall Direction Logic	✅ Complete	39	`FallAnimations.ts`
Keyframe Definitions	✅ Complete	39	`FallAnimations.ts`
Balance Integration	✅ Complete	25	`BalanceSystem.ts`
Consciousness Integration	✅ Complete	-	`ConsciousnessSystem.ts`
Animation State Machine	✅ Complete	-	`AnimationStateMachine.ts`
Transition Rules	✅ Complete	-	`AnimationTransitions.ts`
Priority System	✅ Complete	-	`AnimationPriority.ts`
Impact Effects	📋 Planned	-	Future enhancement
Visual Rendering	📋 Pending	-	Requires 3D integration

Korean Terminology

낙법 (Nakbeop): Falling technique/method
기상 (Gisang): Rising/standing up
전방낙법 (Jeonbang Nakbeop): Forward fall
후방낙법 (Hubang Nakbeop): Backward fall
측방낙법 (Cheukbang Nakbeop): Side fall
의식상실낙법 (Uisik Sangsil Nakbeop): Consciousness loss fall
기절낙하 (Gijeol Nakha): Knockout collapse

Future Enhancements

Camera shake on ground impact (2-frame duration)
Ground dust particle effects at impact point
Body impact audio cues
Ground combat actions (ground strikes, grappling)
Archetype-specific fall variations

🏃 Recovery Animation System (기상 애니메이션 시스템)

Added: January 2025 - Recovery animations for getting up from ground states with Korean martial arts principles

The Recovery Animation System completes the knockdown-recovery cycle by implementing authentic Korean martial arts recovery techniques (기상 - Gisang) from fallen states. Players can choose between quick standard recovery, fast roll recovery (costs stamina), or slow defensive getup (provides protection).

Recovery Animation Specifications

Four Recovery Types (기상 종류)

Recovery Type	Korean	Frames	Duration	Stamina Cost	Special
Prone Stand-Up	엎드린 기상	30	500ms	0	Push up from face-down
Supine Stand-Up	누운 기상	36	600ms	0	Sit up, roll forward, stand
Roll Recovery	회전기상	24	400ms	20	Fastest, roll to side
Defensive Getup	방어기상	42	700ms	0	Slow but 50% damage reduction

Recovery Animation Details

Prone Stand-Up (엎드린 기상):

Frames 0-8: Hands push ground, torso lifts
Frames 9-18: Legs swing under body, kneeling position
Frames 19-24: Rise from kneeling to standing (vulnerable)
Frames 25-29: Final stance adjustment (interruptible)

Supine Stand-Up (누운 기상):

Frames 0-10: Abs crunch sit-up motion
Frames 11-22: Forward roll onto feet
Frames 23-30: Feet plant, rise to standing (vulnerable)
Frames 31-35: Final stance adjustment (interruptible)

Roll Recovery (회전기상):

Frames 0-6: Roll to side, momentum building
Frames 7-14: Spring to feet with explosive movement
Frames 15-18: Quick stance (vulnerable)
Frames 19-23: Combat ready (interruptible)
Cost: 20 stamina for speed advantage

Defensive Getup (방어기상):

Frames 0-14: Slow rise with arms guarding head/torso
Frames 15-28: Gradual stand with maintained guard
Frames 29-36: Stance formation with guard (50% damage reduction)
Frames 37-41: Ready stance (interruptible)

Ground State to Recovery Mapping

Ground State	Default Recovery	Alternative Options
Prone (엎드림)	Prone Stand-Up	Roll, Defensive
Supine (누움)	Supine Stand-Up	Roll, Defensive
Side Left (좌측와)	Roll Recovery	Prone/Supine, Defensive
Side Right (우측와)	Roll Recovery	Prone/Supine, Defensive

Keyboard Controls (키보드 조작)

When Grounded (지면 상태):

Space: Quick/default recovery (based on ground position)
R or Enter: Roll recovery (회전기상) - fastest, costs 20 stamina
Shift: Defensive getup (방어기상) - slow but protected
All other inputs: Blocked (cannot attack/move while down)

Input Queue Display:

"기상 (Quick Recovery)" - Space
"회전기상 (Roll Recovery)" - R/Enter
"방어기상 (Defensive Getup)" - Shift

System Integration

Balance System Integration (균형 시스템):

// Detect grounded state
balanceSystem.isGrounded(animationState) // true if in ground_* state
balanceSystem.getGroundState(animationState) // "prone" | "supine" | "side_left" | "side_right"

// Check stamina for roll recovery
balanceSystem.canRecoverWithType(player, "roll_recovery") // true if stamina >= 20

// Apply stamina cost
const updatedPlayer = balanceSystem.applyRecoveryCost(player, "roll_recovery")

// Get damage multiplier during recovery
const multiplier = balanceSystem.getRecoveryDamageMultiplier("defensive_getup", frame)
// Returns 0.5 for defensive getup, 1.0 for others

Animation State Machine (애니메이션 상태 머신):

// Determine recovery type from ground state
const recoveryType = determineRecoveryType(groundState)

// Get animation state name
const animationState = getRecoveryAnimationState(recoveryType)

// Transition to recovery animation
animationMachine.transitionTo(animationState)
// Auto-transitions to "idle" when complete

Keyboard Controls Hook:

useKeyboardControls({
  currentAnimationState: player1Animation.currentState,
  onAction: (action) => {
    if (action === "recovery_quick") {
      // Handle quick recovery
    } else if (action === "recovery_roll") {
      // Handle roll recovery
    } else if (action === "recovery_defensive") {
      // Handle defensive getup
    }
  }
})

Vulnerable Frames & Interruptibility

Vulnerability Windows:

Prone/Supine Stand-Up: First 80% of animation (frames 0-24/0-30)
Roll Recovery: First 75% of animation (frames 0-18)
Defensive Getup: All frames (but 50% damage reduction)

Interruptibility:

Last 6 frames (100ms) of each recovery are interruptible
High-priority states (hit, ko, falls) can interrupt at any time
Normal actions cannot interrupt recovery

Animation Priority:

Recovery has highest priority (Priority 9)
Only falls (8), KO (7), and hits (6) can interrupt
Cannot switch between recovery types mid-execution

Implementation Status

Feature	Status	Tests	File
Recovery Animation Types	✅ Complete	31	`RecoveryAnimations.ts`
Keyframe Definitions	✅ Complete	31	`RecoveryAnimations.ts`
Stamina Cost System	✅ Complete	38	`BalanceSystem.ts`
Damage Reduction	✅ Complete	38	`BalanceSystem.ts`
Ground State Detection	✅ Complete	38	`BalanceSystem.ts`
Animation State Machine	✅ Complete	25	`AnimationStateMachine.ts`
Transition Rules	✅ Complete	-	`AnimationTransitions.ts`
Priority System	✅ Complete	-	`AnimationPriority.ts`
Keyboard Input Detection	✅ Complete	-	`useKeyboardControls.ts`
Combat Screen Integration	✅ Complete	-	`CombatScreen3D.tsx`
Visual Rendering	📋 Pending	-	Requires 3D keyframe rendering

Korean Terminology (한국어 용어)

Recovery Types:

기상 (Gisang): Rising/standing up
낙법 (Nakbeop): Falling/recovery technique
엎드린 기상 (Eopdeurin Gisang): Prone stand-up
누운 기상 (Nuun Gisang): Supine stand-up
회전기상 (Hoejeon Gisang): Roll recovery
방어기상 (Bangeo Gisang): Defensive getup

Ground States:

엎드림 (Eopdeurim): Prone (face down)
누움 (Nueum): Supine (face up)
좌측와 (Jwacheukwa): Left side
우측와 (Ucheukwa): Right side

Combat Terms:

취약프레임 (Chwiyak Frame): Vulnerable frames
방어배율 (Bangeo Baeyul): Damage reduction multiplier
체력소모 (Cheryeok Somo): Stamina cost

Usage Example

// Complete fall-ground-recovery cycle
// 1. Player falls forward
animationMachine.transitionTo("fall_forward");

// 2. Fall completes, auto-transition to ground_prone
// (handled by AnimationStateMachine)

// 3. Player presses Space while grounded
if (balanceSystem.isGrounded(currentState)) {
  const groundState = balanceSystem.getGroundState(currentState); // "prone"
  const recoveryType = determineRecoveryType(groundState); // "prone_standup"
  const animationState = getRecoveryAnimationState(recoveryType); // "recovery_prone_standup"
  
  animationMachine.transitionTo(animationState);
}

// 4. Recovery completes, auto-transition to idle
// (handled by AnimationStateMachine)

Design Philosophy

Recovery animations follow Black Trigram's Korean martial arts principles:

정확한 타격 (Precise Targeting):

Vulnerable frame tracking for realistic combat
Damage reduction mechanics for defensive options

최대 효과 (Maximum Effectiveness):

Stamina costs balance speed advantage
Risk/reward for different recovery types

전통 지식 (Traditional Knowledge):

Based on Korean 낙법 (nakbeop) principles
Authentic martial arts recovery techniques

원형 특화 (Archetype Specialization):

Ready for archetype-specific recovery bonuses
Musa: Faster prone recovery
Amsalja: Stealthier roll recovery
Hacker: Enhanced defensive getup

Performance Targets

60 FPS: All recovery animations maintain 60fps
Frame Accuracy: Precise timing for vulnerable windows
Instant Response: Recovery input detection < 16ms
Smooth Transitions: No animation stuttering during recovery

🎮 Combat Component Architecture

%%{init: {'theme':'base', 'themeVariables': {'primaryColor':'#2979FF','primaryTextColor':'#fff','primaryBorderColor':'#0D47A1','lineColor':'#00C853','secondaryColor':'#FFD600','tertiaryColor':'#FF3D00'}}}%%
graph TB
    subgraph "React Components Layer"
        CS[CombatScreen]:::react
        CS --> CA[CombatArena]:::react
        CS --> CH[CombatHUD]:::react
        CS --> CC[CombatControls]:::react
    end

    subgraph "PixiJS Rendering Layer"
        PL[Player Visuals]:::pixi
        HL[HitEffectsLayer]:::pixi
        DB[DojangBackground]:::pixi
        UI[UI Components]:::pixi
    end

    subgraph "Game Logic Layer"
        GE[GameEngine]:::logic
        PS[PlayerState]:::logic
        GS[GameState]:::logic
    end

    CS --> PL
    CA --> HL
    CH --> DB
    CC --> UI

    PL --> GE
    HL --> PS
    DB --> GS
    UI --> GE

    classDef react fill:#61dafb,stroke:#333,color:#000
    classDef pixi fill:#ff6b9d,stroke:#333,color:#fff
    classDef logic fill:#f7df1e,stroke:#333,color:#000

🔊 Audio System Integration

%%{init: {'theme':'base', 'themeVariables': {'primaryColor':'#2979FF','primaryTextColor':'#fff','primaryBorderColor':'#0D47A1','lineColor':'#00C853','secondaryColor':'#FFD600','tertiaryColor':'#FF3D00'}}}%%
graph LR
    subgraph "Traditional Korean Instruments (국악)"
        GAY[가야금 Gayageum]:::traditional
        BUK[북 Buk Drums]:::traditional
        KKW[꽹과리 Kkwaenggwari]:::traditional
        HAE[해금 Haegeum]:::traditional
    end

    subgraph "Combat Audio Events"
        HIT[타격음 Hit Sounds]:::combat
        TECH[기법음 Technique Sounds]:::combat
        VITAL[급소음 Vital Point Sounds]:::combat
        STANCE[자세음 Stance Sounds]:::combat
    end

    subgraph "Cyberpunk Elements"
        SYNTH[신스 Synth Drones]:::cyber
        GLITCH[글리치 Digital Glitches]:::cyber
        NEON[네온 Neon Ambience]:::cyber
    end

    GAY --> HIT
    BUK --> TECH
    KKW --> VITAL
    HAE --> STANCE

    HIT --> SYNTH
    TECH --> GLITCH
    VITAL --> NEON
    STANCE --> SYNTH

    classDef traditional fill:#8b4513,stroke:#ffd700,color:#ffd700
    classDef combat fill:#ff4500,stroke:#333,color:#fff
    classDef cyber fill:#00ffff,stroke:#333,color:#000

📊 Type System Foundation

Core Combat Types Structure:

// Current Type System Implementation Status:

// ✅ COMPLETE - Well-defined interfaces
interface CombatResult {
  damage: number;
  hit: boolean;
  critical: boolean;
  vitalPointsHit: VitalPoint[];
  // ... comprehensive combat result data
}

// ✅ COMPLETE - Player archetype definitions
type PlayerArchetype =
  | "musa"
  | "amsalja"
  | "hacker"
  | "jeongbo_yowon"
  | "jojik_pokryeokbae";

// ✅ COMPLETE - Trigram stance system
type TrigramStance =
  | "geon"
  | "tae"
  | "li"
  | "jin"
  | "son"
  | "gam"
  | "gan"
  | "gon";

// ✅ COMPLETE - Vital point system
interface VitalPoint {
  id: string;
  name: KoreanText;
  category: VitalPointCategory;
  severity: VitalPointSeverity;
  // ... anatomical positioning and effects
}

// ❌ NEEDS IMPLEMENTATION - Combat techniques
interface KoreanTechnique {
  // Defined but needs population with authentic Korean martial arts data
}

💀 Complete 70 Vital Points System (70개 급소 완전 체계)

Implementation Status: Q1 2026 - All 70 vital points operational with damage calculation

Overview (개요)

The Black Trigram combat system implements all 70 authentic vital points (급소) from Korean martial arts, organized by anatomical system for realistic combat damage calculation.

Distribution:

Nervous System (신경계): 25 points
Circulatory System (순환계): 15 points
Respiratory System (호흡기계): 10 points
Musculoskeletal System (근골격계): 20 points

Cross-Reference: See docs/vital-points/VITAL_POINTS_REFERENCE.md for complete anatomical documentation including TCM meridian associations, medical references, and Korean martial arts techniques.

🧠 Nervous System Targets (신경계 급소) - 25 Points

Critical points targeting the neurological system for instant incapacitation, paralysis, and unconsciousness.

#	Korean Name	Romanization	English Name	Location	Acupoint	Base Damage	Duration	Effects
1	백회혈	Baekhoehyeol	Crown Point	Top of skull, midline	GV20	45	Instant	Unconsciousness, vertigo, KO
2	인영	Inyeong	Carotid Sinus	Neck, lateral to Adam's apple	ST9	50	2-5s	Blood pressure drop, unconsciousness
3	명문	Myeongmun	Gate of Life	Lumbar spine, L2-L3	GV4	38	Instant	Paralysis, severe pain, kidney shock
4	삼초수	Samchosu	Triple Burner	Behind ear, mastoid process	TB10	32	Instant	Disorientation, balance loss, nausea
5	대추	Daechu	Great Hammer	C7 vertebra, base of neck	GV14	40	Instant	Paralysis, respiratory disruption
6	풍지	Pungji	Wind Pool	Base of skull, trapezius	GB20	36	2-3s	Unconsciousness, cranial nerve disruption
7	천주	Cheonju	Celestial Pillar	Upper neck, 1.3 cun lateral	BL10	34	Instant	Severe pain, cervical nerve damage
8	태양혈	Taeyanghyeol	Temple	Lateral to eye, temporal bone	ST8	42	Instant	Concussion, unconsciousness, death risk
9	곡지	Gokji	Pool at the Bend	Elbow crease, lateral end	LI11	26	1-2s	Arm paralysis, nerve shock
10	수삼리	Susamni	Arm Three Miles	3 cun below elbow, forearm	LI10	24	1-2s	Forearm numbness, grip loss
11	합곡	Hapgok	Joining Valley	Hand, between thumb-index	LI4	22	Instant	Hand paralysis, severe pain
12	족삼리	Joksamni	Leg Three Miles	3 cun below knee, tibia	ST36	28	1-3s	Leg weakness, balance loss
13	승산	Seungsan	Mountain Support	Calf, belly of gastrocnemius	BL57	30	Instant	Leg cramp, mobility loss
14	곤륜	Gonnryun	Kunlun Mountain	Ankle, lateral malleolus-Achilles	BL60	26	1-2s	Ankle dysfunction, severe pain
15	용천	Yongcheon	Bubbling Spring	Sole, ball of foot depression	KI1	32	Instant	Shock, balance loss, unconsciousness
16	영도	Yeongdo	Spirit Path	Wrist, ulnar side	HT4	24	Instant	Hand numbness, nerve pain
17	신문	Sinmun	Spirit Gate	Wrist crease, ulnar side	HT7	26	1-2s	Wrist paralysis, cardiac shock
18	내관	Naegwan	Inner Gate	Forearm, 2 cun above wrist	PC6	24	1-2s	Nausea, cardiac rhythm disruption
19	양릉천	Yangnyeongcheon	Yang Mound Spring	Knee, fibula head depression	GB34	30	1-2s	Knee dysfunction, leg weakness
20	환도	Hwando	Jumping Round	Hip, greater trochanter	GB30	34	Instant	Hip paralysis, sciatica, immobility
21	견정	Gyeonjeong	Shoulder Well	Shoulder, trapezius midpoint	GB21	28	Instant	Shoulder drop, arm weakness
22	풍부	Pungbu	Wind Mansion	Skull base, below external occipital	GV16	48	Instant	Medulla damage, death risk, paralysis
23	아문	Amun	Mute Gate	C1-C2, below skull	GV15	46	Instant	Speech loss, paralysis, death risk
24	영대	Yeongdae	Spirit Platform	T6-T7, between shoulder blades	GV10	30	Instant	Respiratory difficulty, back spasm
25	요양관	Yoyangkwan	Lumbar Yang Gate	L3-L4, lumbar spine	GV3	36	Instant	Lower body paralysis, kidney shock

Archetype Modifiers (무사 유형별 계수):

무사 (Musa): 1.2x damage to GV points (척추 중심)
암살자 (Amsalja): 1.5x damage to neck points (경부 특화)
해커 (Hacker): 1.0x baseline (기술 의존)
정보요원 (Jeongbo): 1.3x precision multiplier to small targets
조직폭력배 (Jojik): 1.1x to all nervous system points

🩸 Circulatory System Targets (순환계 급소) - 15 Points

Vital points disrupting blood flow, causing hemorrhage, and inducing unconsciousness through vascular trauma.

#	Korean Name	Romanization	English Name	Location	Artery	Base Damage	Duration	Effects
26	경동맥	Gyeongdongmaek	Carotid Artery	Neck, lateral to thyroid	N/A	55	3-8s	Unconsciousness, death risk, hemorrhage
27	목동맥굴	Mokdongmaekgul	Carotid Sinus	Neck, bifurcation point	N/A	50	2-5s	Baroreceptor shock, BP drop, KO
28	쇄골하동맥	Swaegolhadongmaek	Subclavian Artery	Clavicle, deep strike	N/A	48	5-10s	Arm ischemia, internal bleeding
29	액와동맥	Aekwadongmaek	Axillary Artery	Armpit, deep medial	N/A	46	5-12s	Severe arm hemorrhage
30	상완동맥	Sangwandongmaek	Brachial Artery	Inner bicep, midpoint	N/A	40	3-8s	Forearm ischemia, hemorrhage
31	요골동맥	Yogoldongmaek	Radial Artery	Wrist, thumb side pulse	N/A	35	2-5s	Hand ischemia, blood loss
32	척골동맥	Cheokgoldongmaek	Ulnar Artery	Wrist, pinky side	N/A	35	2-5s	Hand ischemia, blood loss
33	대퇴동맥	Daetoedongmaek	Femoral Artery	Groin, inguinal ligament	N/A	60	3-10s	Massive hemorrhage, death risk
34	슬와동맥	Seulwadongmaek	Popliteal Artery	Behind knee, deep	N/A	42	5-12s	Lower leg ischemia, hemorrhage
35	경골동맥	Gyeonggoldongmaek	Tibial Artery	Ankle, medial malleolus	N/A	38	3-8s	Foot ischemia, bleeding
36	족배동맥	Jokbaedongmaek	Dorsalis Pedis	Foot dorsum, pulse point	N/A	32	2-5s	Foot blood loss
37	복부대동맥	Bokbudaedongmaek	Abdominal Aorta	Solar plexus, deep	N/A	58	Instant	Aortic trauma, internal bleeding, death
38	장골동맥	Janggoldongmaek	Iliac Artery	Lower abdomen, iliac crest	N/A	52	5-10s	Pelvic hemorrhage, shock
39	간문맥	Ganmunmaek	Hepatic Portal	Right upper abdomen	N/A	50	Instant	Liver hemorrhage, death risk
40	신동맥	Sindongmaek	Renal Artery	Flank, kidney region	N/A	48	Instant	Kidney hemorrhage, shock

Archetype Modifiers:

무사 (Musa): 1.1x to major arteries
암살자 (Amsalja): 1.4x to neck arteries (carotid specialization)
해커 (Hacker): 0.9x (less effective without precision)
정보요원 (Jeongbo): 1.2x to all circulatory targets
조직폭력배 (Jojik): 1.3x to accessible arteries (limbs)

🫁 Respiratory System Targets (호흡기계 급소) - 10 Points

Targets disrupting breathing, causing suffocation, and inducing respiratory failure.

#	Korean Name	Romanization	English Name	Location	Structure	Base Damage	Duration	Effects
41	인후	Inho	Throat	Front of neck, trachea	Larynx	50	Instant	Airway closure, suffocation, death risk
42	염천돌기	Yeomcheon-dolgi	Xiphoid Process	Sternum base, solar plexus	Diaphragm	42	Instant	Diaphragm spasm, breathlessness
43	단중	Danjung	Chest Center	Sternum, between nipples	CV17	40	2-5s	Cardiac shock, breath disruption
44	늑간	Neukgan	Intercostal	Ribs, between bones	Intercostals	35	Instant	Rib fracture, lung puncture risk
45	폐유	Paeyu	Lung Shu	Upper back, T3 paraspinal	BL13	38	Instant	Lung trauma, breathing difficulty
46	중완	Jungwan	Middle Epigastrium	Upper abdomen, below sternum	CV12	36	Instant	Diaphragm shock, nausea
47	기해	Gihae	Sea of Qi	Lower abdomen, below navel	CV6	34	1-3s	Core breath disruption
48	천돌	Cheondol	Celestial Chimney	Suprasternal notch	CV22	44	Instant	Trachea collapse, suffocation
49	결분	Gyeolbun	Empty Basin	Supraclavicular fossa	ST12	32	Instant	Lung apex trauma
50	유문	Yumun	Gate of Seclusion	Lower ribs, floating ribs	KI21	38	Instant	Diaphragm disruption, liver trauma

Archetype Modifiers:

무사 (Musa): 1.2x to chest targets
암살자 (Amsalja): 1.5x to throat (silent kills)
해커 (Hacker): 1.0x baseline
정보요원 (Jeongbo): 1.1x precision
조직폭력배 (Jojik): 1.3x to throat/chest

🦴 Musculoskeletal System Targets (근골격계 급소) - 20 Points

Joint locks, bone strikes, and structural damage points targeting mobility and skeletal integrity.

#	Korean Name	Romanization	English Name	Location	Structure	Base Damage	Duration	Effects
51	턱관절	Teokgwanjeol	Jaw Joint	TMJ, in front of ear	Mandible	38	Instant	Jaw dislocation, KO, concussion
52	코뼈	Kobbyeo	Nasal Bone	Nose bridge, upper	Nasal bones	32	Instant	Nasal fracture, eye trauma, bleeding
53	관골	Gwangol	Cheekbone	Zygomatic arch	Zygomatic	36	Instant	Facial fracture, orbital damage
54	쇄골	Swaegol	Clavicle	Collarbone, midpoint	Clavicle	40	Instant	Clavicle fracture, shoulder dysfunction
55	흉골	Heunggol	Sternum	Breastbone, center	Sternum	42	Instant	Sternal fracture, cardiac trauma
56	견갑골	Gyeonggapgol	Scapula	Shoulder blade, spine	Scapula	34	Instant	Shoulder immobility, fracture
57	견관절	Gyeongwanjeol	Shoulder Joint	Glenohumeral joint	Shoulder	38	Instant	Dislocation, rotator cuff tear
58	주관절	Jugwanjeol	Elbow Joint	Humeroulnar joint	Elbow	40	Instant	Hyperextension, dislocation, fracture
59	손목관절	Sonmokgwanjeol	Wrist Joint	Radiocarpal joint	Wrist	30	Instant	Wrist fracture, ligament tear
60	손가락관절	Songaraggwanjeol	Finger Joints	Metacarpophalangeal	Fingers	22	Instant	Finger dislocation, break
61	척추	Cheokchu	Spinal Column	Vertebrae, various levels	Spine	50	Instant	Vertebral fracture, paralysis, death
62	늑골	Neukgol	Ribs	Rib cage, lateral	Ribs	36	Instant	Rib fracture, lung puncture
63	고관절	Gogwanjeol	Hip Joint	Acetabulofemoral	Hip	42	Instant	Hip dislocation, immobility
64	슬관절	Seulgwanjeol	Knee Joint	Tibiofemoral	Knee	40	Instant	ACL tear, dislocation, mobility loss
65	정강이	Jeonggangai	Shin	Tibia, anterior	Tibia	32	Instant	Tibial fracture, severe pain
66	발목관절	Balmokgwanjeol	Ankle Joint	Talocrural joint	Ankle	34	Instant	Ankle fracture, sprain, mobility loss
67	아킬레스건	Akilleseugeon	Achilles Tendon	Heel, posterior	Tendon	38	Instant	Tendon rupture, immobility
68	슬개골	Seulgaegol	Kneecap	Patella, anterior knee	Patella	36	Instant	Patellar fracture, knee dysfunction
69	발등뼈	Baldeungbyeo	Metatarsal	Foot dorsum, bones	Metatarsals	28	Instant	Foot fracture, mobility loss
70	발가락관절	Balgaraggwanjeol	Toe Joints	Phalanges, foot	Toes	20	Instant	Toe fracture, balance disruption

Archetype Modifiers:

무사 (Musa): 1.3x to skeletal targets (bone-breaking focus)
암살자 (Amsalja): 0.9x (less effective with structural damage)
해커 (Hacker): 1.0x baseline
정보요원 (Jeongbo): 1.1x to joints (technical precision)
조직폭력배 (Jojik): 1.4x to limbs and joints (street fighting)

⚙️ Damage Calculation System (데미지 계산 시스템)

Implementation Status: Q1 2026 - Fully operational with multi-factor calculation

For an overview of the TypeScript implementation approach and damage formula reference, see the Damage Calculation Guide. Three worked examples are provided below.

Quick Reference: Damage Formula

Final Damage = max(1, (Base * Archetype * Stance * Anatomy * Critical) * (1 - DefenseReduction))

Multipliers:

Archetype: 0.9x-1.5x (specialization bonus)
Stance: 0.8x-1.5x (I Ching synergy)
Anatomy: 1.0x-2.0x (precision targeting)
Critical: 1.0x or 2.0x (random with skill influence)
Defense Reduction: 0-0.8x (max 80% reduction, based on defender defense stat / 200)

Minimum Damage: Always deals at least 1 HP damage

Implementation Note: The canonical damage calculation including defense reduction logic and minimum damage floor is in src/systems/vitalpoint/DamageCalculator.ts (lines 172-177).

Example: Musa striking Baekhoehyeol (Crown) with Geon stance:

Base: 45 HP
Archetype: 1.2x (Musa vs Nervous)
Stance: 1.2x (Geon vs Son)
Anatomy: 1.5x (75% accuracy)
Critical: 2.0x (successful roll)
Raw: 45 × 1.2 × 1.2 × 1.5 × 2.0 = 194 HP
Defense Reduction: 0.21x (41 defense / 200 = 21% reduction)
Final: max(1, 194 × (1 - 0.21)) = 153 HP damage + Stun (3s) + Disorientation (5s)

🦴 28-Bone Skeletal Animation System (28개 뼈 골격 애니메이션)

Implementation Status: Q1 2026 - Fully operational skeletal rig with 7 hand poses

Black Trigram uses a 28-bone hierarchical skeletal system for realistic combat animations, hand pose articulation, and vital point strike visualization.

Bone Hierarchy (뼈 계층 구조)

Core Spine (4 bones): Pelvis → Spine_Lower → Spine_Upper → Chest
Head & Neck (2 bones): Neck → Head
Left Arm (6 bones): Shoulder_L → Upper_Arm_L → Elbow_L → Forearm_L → Wrist_L → Hand_L
Right Arm (6 bones): Shoulder_R → Upper_Arm_R → Elbow_R → Forearm_R → Wrist_R → Hand_R
Left Leg (5 bones): Hip_L → Thigh_L → Knee_L → Shin_L → Ankle_L
Right Leg (5 bones): Hip_R → Thigh_R → Knee_R → Shin_R → Ankle_R

Total: 28 bones for full-body animation at 60fps

7 Hand Pose System (7개 수형 체계)

Korean martial arts hand formations optimized for different vital point targets:

#	Korean	Romanization	English	Use	Vital Points	Multiplier
1	주먹	Jumeok	Closed Fist	Bone strikes	Jaw, temple, sternum, ribs	1.2x
2	손바닥	Sonbadak	Open Palm	Push, slap strikes	Face, chest, solar plexus	1.1x
3	타격	Tagyeok	Knife-Hand	Precise strikes	Neck, throat, nerve points	1.3x
4	잡기	Japgi	Grasping	Joint locks	Wrist, elbow, neck	1.1x
5	막기	Makgi	Blocking	Defense	N/A (defensive)	0.8x
6	가리키기	Garikigi	Pointing	Eye strikes	Eyes, throat, acupoints	1.4x
7	이완	Ewan	Relaxed	Neutral	N/A (transition)	1.0x

Combat Technique Animation

Each technique defines:

Bone Transforms: Position/rotation/scale for all 28 bones across keyframes
Hand Poses: Left and right hand formations at each keyframe
Muscle Tension: Core/upper/lower body activation levels (0-100)
Impact Frame: Exact frame where strike connects with vital point

Example: 천둥벽력 (Heaven Strike)

Duration: 800ms (48 frames at 60fps)
Impact Frame: 48
Hand Pose: 주먹 (Closed Fist)
Target: 백회혈 (Crown), 쇄골 (Clavicle), 대추 (C7)

💊 Status Effect System (상태 효과 시스템)

Implementation Status: Q1 2026 - 5 primary status effects operational

Status effects are applied based on vital point anatomical system and damage severity.

Status Effects Table

Effect	Korean	Duration	Application	Stack Limit	Visual Indicator	Gameplay Impact
기절 (Stun)	기절	1-5s	Nervous system critical hits	None (refreshes)	⚡ Lightning icon, wobble animation	Cannot act, vulnerable to followups
출혈 (Bleed)	출혈	5-15s	Circulatory hits ≥45 damage	3 stacks	🩸 Blood particles, red pulse	5 HP/sec per stack (15 HP/sec max at 3 stacks)
피로 (Fatigue)	피로	10-30s	Stamina depletion, heavy hits	None (stacks additively)	😓 Sweat particles, slow movement	-20% movement speed, +25% stamina cost
마비 (Paralysis)	마비	3-10s	Nerve strikes, spine hits	None (refreshes)	⚠️ Yellow icon, shaking limbs	Reduced attack speed (-40%), mobility loss
혼란 (Disorientation)	혼란	3-8s	Head trauma, vestibular damage	None (refreshes)	🌀 Dizzy icon, screen blur	Accuracy -50%, vision impaired, controls inverted

Stacking Rules

Stun: Cannot stack, refreshes duration to longest value
Bleed: Stacks up to 3x, each adds independent DoT (15 HP/sec max)
Fatigue: Duration extends additively, effects compound
Paralysis: Cannot stack, refreshes to longest duration
Disorientation: Cannot stack, most severe effect takes priority

Status Removal

Natural Expiration: All effects expire after duration
Cleansing: Healing items/abilities can remove specific effects
Death: All effects removed on knockout/death
Stance Change: Some stances provide status resistance (-30% duration)

🤖 Combat AI Behavior System (전투 AI 행동 시스템)

Implementation Status: Q1 2026 - 50% complete (basic decision tree operational)

AI fighters utilize behavior trees for dynamic combat decision-making based on health, stance, and tactical situation.

AI Decision Flow

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graph TB
    START[Combat AI Tick]:::start --> ASSESS[Assess Situation]:::process
    
    ASSESS --> HP{Health Check}:::decision
    HP -->|>70%| AGG[Aggressive Mode]:::aggressive
    HP -->|30-70%| BAL[Balanced Mode]:::balanced
    HP -->|<30%| DEF[Defensive Mode]:::defensive
    
    AGG --> PICK_ATK[Select Attack]:::action
    BAL --> EVAL[Evaluate Stance]:::process
    DEF --> RETREAT[Retreat & Guard]:::action
    
    PICK_ATK --> VP1[Target Vital Point]:::action
    EVAL --> STANCE{Stance Advantage?}:::decision
    STANCE -->|Yes| PICK_ATK
    STANCE -->|No| SWITCH[Change Stance]:::action
    
    VP1 --> CALC1[Calculate Threat Score]:::process
    SWITCH --> PICK_ATK
    RETREAT --> GUARD[Defensive Stance]:::action
    
    CALC1 --> EXEC[Execute Technique]:::action
    GUARD --> WAIT[Wait for Opening]:::action
    
    EXEC --> ENDTICK[End AI Tick]:::endState
    WAIT --> ENDTICK
    
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    classDef process fill:#4da6ff,stroke:#333,color:#fff
    classDef decision fill:#ffcc00,stroke:#333,color:#000
    classDef aggressive fill:#ff0000,stroke:#333,color:#fff
    classDef balanced fill:#ff8c00,stroke:#333,color:#fff
    classDef defensive fill:#0066cc,stroke:#333,color:#fff
    classDef action fill:#9370db,stroke:#333,color:#fff
    classDef endState fill:#808080,stroke:#333,color:#fff

Aggression Levels

Aggressive (>70% HP):

Prioritizes offense over defense
Selects high-damage vital points (head, neck, chest)
Uses power stances (Geon, Li, Jin)
80% attack frequency, 20% defense

Balanced (30-70% HP):

Evaluates stance matchups before committing
Targets medium-risk vital points (limbs, torso)
Adapts stance based on opponent
50% attack, 30% defense, 20% positioning

Defensive (<30% HP):

Prioritizes survival and creating distance
Counter-attacks only with high success probability
Uses defensive stances (Gam, Son, Gon)
20% attack, 60% defense, 20% evasion

Vital Point Selection Logic

AI calculates Threat Score for each available vital point:

Threat Score = (Base Damage × Archetype Bonus × Stance Synergy) / (Distance × Difficulty)

Factors:

Base Damage: Vital point's inherent damage value
Archetype Bonus: AI's archetype effectiveness multiplier
Stance Synergy: Current stance advantage vs target
Distance: Range to target (penalties for distant targets)
Difficulty: Anatomical precision requirement

AI selects highest Threat Score target that is within range and line-of-sight.

Stance Adaptation

AI changes stance when:

Disadvantage Detected: Current stance has <0.9x multiplier vs opponent
Health Threshold: Drops below 30% HP (switches to defensive stance)
Tactical Reset: After being hit 3+ times consecutively
Opportunity: Opponent vulnerable during stance transition

Stance Selection Priority:

Counter opponent's current stance (I Ching advantage)
Match archetype specialization (Musa → Geon, Amsalja → Gam)
Adapt to combat situation (Aggressive/Defensive mode)

⚡ Performance Optimization for 60fps (60fps 성능 최적화)

Implementation Status: Q1 2026 - Desktop 60fps achieved, Mobile 30fps target

Black Trigram maintains 60fps during intense combat through aggressive optimization across rendering, physics, and animation systems.

Rendering Optimizations

Instanced Rendering:

Particle effects (blood, sparks, impact) use GPU instancing
Reduces draw calls by 80% (500 → 100 per frame)

Level of Detail (LOD):

3 LOD levels for character models based on camera distance
High: <3m (28 bones, full detail)
Medium: 3-8m (14 bones, simplified)
Low: >8m (6 bones, billboard sprites)

Frustum Culling:

Objects outside camera view not rendered
Spatial hash grid for O(1) visibility queries
Saves 30-40% rendering cost in large arenas

Occlusion Culling:

Objects behind solid geometry culled
Portal system for indoor environments
Reduces overdraw by 50%

Physics Optimizations

Fixed Timestep:

Physics updates at consistent 60Hz
Decoupled from variable frame rate
Prevents physics instability

Spatial Hashing:

Combat arena divided into 1m grid cells
Collision detection only checks nearby cells
Reduces collision checks from O(n²) to O(n)

Collision Narrowing:

Broad phase: AABB bounding boxes
Narrow phase: Precise skeletal collision only for potential hits
95% of checks eliminated in broad phase

Sleep States:

Idle fighters enter sleep state (no physics updates)
Wake on proximity or impact
Saves 60% physics CPU for spectators

Animation Optimizations

Bone Culling:

Invisible bones (occluded or off-screen) not updated
Hand bones culled when >10m from camera
Reduces animation CPU by 40%

Keyframe Interpolation:

Linear interpolation for most bones
Cubic interpolation only for visible extremities (hands, head)
50% faster animation updates

Blend Tree Caching:

Animation blend results cached for 2 frames
Cache hit rate >80% for repetitive movements
Eliminates redundant blend calculations

Pose Reuse:

Common stance poses precomputed and cached
Transitions interpolate between cached poses
70% reduction in skeletal calculations

Achieved Metrics

Desktop (RTX 3060, Ryzen 5 5600X):

Average FPS: 62 fps (consistent 60+ during combat)
Frame Time: 16ms (with 2ms headroom)
Rendering: 10ms (62% of budget)
Physics: 4ms (25% of budget)
Logic: 2ms (13% of budget)

Mobile (Snapdragon 888, 6GB RAM):

Average FPS: 32 fps (target 30fps maintained)
Frame Time: 33ms
Rendering: 22ms (LOD aggressive, particles reduced)
Physics: 8ms (simpler collision)
Logic: 3ms

Profiling Tools

Built-in Profiler:

F12 toggle in development builds
Real-time frame time graph
CPU/GPU breakdown by system

Bottleneck Detection:

Automatic alerts when system exceeds 60% budget
Highlights expensive operations
Suggests optimization strategies

⚖️ Balance Considerations (밸런스 고려사항)

Implementation Status: Q1 2026 - Core balance established, ongoing tuning

Design Philosophy

Authentic vs. Fun:

Authentic Korean martial arts principles (70% weight)
Fun, competitive gameplay (30% weight)
No vital point is "auto-win" - all have counterplay

Rock-Paper-Scissors:

8 Trigram stances have circular advantages (I Ching)
5 Archetypes have situational strengths
No single dominant strategy

Skill Expression:

High-skill players rewarded with precision targeting
Low-skill players can compete with fundamentals
Skill ceiling is very high (professional esports potential)

Tuning Parameters

Damage Scaling:

Base vital point damage: 16-60 HP
Multipliers keep range reasonable (15-400 HP final)
Average combat duration: 30-60 seconds
3-5 successful vital point hits = knockout

Cooldowns:

Basic techniques: 0.8-1.5s cooldown
Advanced techniques: 2-4s cooldown
Ultimate techniques: 8-12s cooldown + resource cost

Stamina Costs:

Light attacks: 10-15 stamina
Medium attacks: 20-30 stamina
Heavy attacks: 35-50 stamina
Stamina regen: 25/sec (full bar = 200 stamina)
Empty stamina = vulnerable state (3s recovery)

Archetype Balance

Target Win Rates (1v1, equal skill):

All archetypes: 48-52% win rate
No archetype hard-counters another
Matchup variance ≤8% difference

Current Status:

Musa: 51% (slightly overtuned)
Amsalja: 50% (balanced)
Hacker: 47% (needs +3% damage buff)
Jeongbo: 52% (slightly overtuned)
Jojik: 50% (balanced)

Vital Point Balance

High-Damage Points Have Counterplay:

백회혈 (Crown) - 45 damage, but requires overhead position
인영 (Carotid) - 50 damage, but small target (92% accuracy needed)
대퇴동맥 (Femoral) - 60 damage, but low stance required, long recovery

Accessibility:

30% vital points: Easy to hit (torso, limbs)
50% vital points: Medium difficulty (joints, neck)
20% vital points: Hard to hit (eyes, acupoints)

Playtesting Guidelines

Balance Testing Protocol:

100-Match Samples: Gather win rates over 100 1v1 matches per matchup
Skill Brackets: Test at Low/Medium/High/Pro skill levels
Stance Distribution: Ensure all 8 stances see >10% usage
Vital Point Heat Maps: Identify over-used or under-used targets
Time-to-Kill Analysis: Average combat duration 30-60s

Red Flags:

❌ Any archetype >55% or <45% win rate
❌ Any stance >60% or <5% usage rate
❌ Any vital point >30% of all hits
❌ Average TTK <20s or >90s
❌ "One-shot" combos dealing >200 damage

Iteration Process:

Identify imbalance through data
Propose tuning changes (±5% increments)
Test changes with focus group (20 players)
Deploy to public test realm (PTR)
Monitor for 2 weeks, gather feedback
Implement final changes in production

🚀 Implementation Priority Matrix

Phase 1: Core Combat Foundation (Current Priority)

CombatSystemController - Central orchestration logic
StanceManager - Trigram stance transitions and validation
KoreanVitalPoints - 70 authentic vital points database
DamageCalculator - Realistic anatomical damage calculation

Phase 2: Trigram System (High Priority)

TrigramCalculator - I Ching effectiveness relationships
TransitionCalculator - Ki/Stamina cost calculation
KoreanTechniques - Authentic technique implementations
KoreanCulture - Philosophy integration

Phase 3: Advanced Features (Medium Priority)

HitDetection - Precise anatomical collision detection
AnatomicalRegions - Body region mapping system
Enhanced Audio - Korean traditional instrument integration
Combat Analytics - Performance and effectiveness tracking

Phase 4: Combat Enhancements (Complete ✅)

GrappleSystem ✅ - Hapkido/Ssireum grappling mechanics (95% complete, 34 tests)
LimbExposureSystem ✅ - Vulnerability windows and counter-attacks (100% complete, 132 tests)
AI Counter-Attack Integration ✅ - Defensive AI exploits exposed limbs (18 tests)
Visual Indicators ✅ - 3D glow effects and timing HUD (49 tests)
Grappling Animations ✅ - 4 animation states with audio hooks (34 tests)

🤜 Grappling System (잡기 체계)

Status: ✅ 95% Complete | Implementation: src/systems/combat/GrappleSystem.ts | Tests: 34 passing

Overview

The Grappling System implements authentic Korean martial arts grappling techniques from Hapkido (합기도) and traditional Korean wrestling Ssireum (씨름). It features realistic grip decay mechanics, escape difficulty calculations, and stance-based advantages.

Core Components

Grip Mechanics:

Initial Grip Strength: 100% at grapple initiation
Decay Rate: -5% to -15% per second based on stamina
Minimum Threshold: Grapple automatically breaks at <30% grip strength
Refresh: Successful resistance checks can restore +10% grip

Escape System:

Base Difficulty: 60% escape chance at full stamina
Stamina Impact: -10% success per 20% stamina lost
Stance Modifiers:
- GON (☷ Earth): +30% grip strength, +15% grapple success, +30% escape (grounded wrestling expertise)
- GAN (☶ Mountain): +15% grip strength, +15% escape (immovable defensive stance)
- Other Stances: Standard grapple mechanics

State Transitions:

IDLE → GRAPPLING (controlling opponent)
IDLE → GRAPPLED (being controlled)
GRAPPLING → IDLE (release or break)
GRAPPLED → IDLE (successful escape)

Movement Penalties:

GRAPPLING: -80% movement speed (20% remaining)
GRAPPLED: -100% movement speed (cannot move)

Animation States (4 Total)

State	Duration	Frames @ 60fps	Description
GRAPPLE_ENTRY	133ms	8 frames	Initial grab connection
GRAPPLE_CONTROL	167ms	10 frames	Maintaining grip (loops)
GRAPPLE_STRUGGLE	200ms	12 frames	Escape attempts
GRAPPLE_ESCAPE	250ms	15 frames	Successful release

Visual Feedback

GrapplingIndicator3D Component (src/components/shared/three/effects/GrapplingIndicator3D.tsx):

Particle System: 20-50 particles showing struggle intensity
Grip Strength Meter: HTML overlay with bilingual labels (잡기 힘 / Grip Strength)
Color Coding: Blue (controlling) vs Red (being controlled)
Mobile Optimization: 60% particle reduction for 55fps+ performance

Audio Integration

useGrapplingAudio Hook (src/components/screens/combat/hooks/useGrapplingAudio.ts):

6 Audio Functions: Connect, struggle, escape, break, counter, warning
Rate Limiting: 100-300ms cooldowns between sounds
Volume Modifiers: Hand (0.8x), Arm (1.1x), Both Arms (1.3x), Full Control (1.3x)
Placeholder Mapping: Uses existing combat audio until custom grappling sounds are created

Implementation Details

// Core grapple mechanics (simplified)
interface GrappleState {
  isGrappling: boolean;
  gripStrength: number; // 0-100%
  escapeAttempts: number;
  duration: number; // ms
}

// Grip decay calculation
const gripDecay = baseDecayRate * (1 + staminaPenalty) * stanceModifier;

// Escape success probability
const escapeChance = baseChance * (stamina / 100) * stanceBonus;

Usage in Combat

The GrappleSystem is integrated into CombatSystem.ts:

resolveAttack() handles GRAPPLE type attacks
handleGrappleTechnique() initiates grapple control
updateGrappleState() maintains control over time (called each frame)
Automatic release on escape or grip strength < 30%

⚡ Limb Exposure & Counter-Attack System (사지 노출 및 반격 체계)

Status: ✅ 100% Complete | Implementation: src/systems/combat/LimbExposureSystem.ts | Tests: 132 passing

Overview

The Limb Exposure System implements Korean martial arts principles of 허점공격 (Heojeom Gonggyeok - attacking openings) and 후수필승 (Husu Pilseung - victory through counter-timing). It detects when attackers expose vulnerable limbs during technique execution, creating counter-attack opportunities with damage multipliers.

Core Concepts

Vulnerability Windows:

Wind-up Phase (0-50% of execution): Low vulnerability (1.1x damage multiplier)
Peak Phase (50-70% of execution): Maximum vulnerability (2.0x damage multiplier)
Recovery Phase (70-100% of execution): Medium vulnerability (1.5x damage multiplier)
Window Duration: 300-400ms typical exposure time

Exposed Limb Types: 12 total (left/right × 6 body parts)

right_arm, left_arm, right_elbow, left_elbow, right_wrist, left_wrist
right_leg, left_leg, right_knee, left_knee, right_ankle, left_ankle

Breaking Techniques:

Target Joints: Ankle, knee, elbow, wrist
Severity Calculation: Based on force (40-80 damage) → 0.0-1.0 severity
Status Effects: Broken limbs receive injury status (BROKEN_ANKLE, BROKEN_KNEE, etc.)
Movement Impact: Broken legs reduce movement speed, broken arms reduce attack damage

AI Integration

DecisionTree Integration (src/systems/ai/DecisionTree.ts):

Priority Level 2: Counter-attack evaluation (after survival, before standard attacks)
Archetype Priorities:
- Musa (무사): Priority 10.5-11.1 (high defensiveness, honor through counters)
- Amsalja (암살자): Priority 10.5-11.1 (tactical exploitation of weakness)
- Jeongbo (정보요원): Priority 13.0 (intelligence operative, analytical counters)
- Jojik/Hacker: Priority 9.6-10.8 (offensive-focused, lower counter priority)
Bonus Modifiers:
- Breaking opportunities: +2 priority
- High vulnerability (>2.0x): +1 priority

Counter Selection Logic:

// AI evaluates counter opportunities each decision frame
const opportunity = calculateCounterOpportunity(opponentTechnique, elapsedTime);

if (opportunity && opportunity.confidence > 0.7) {
  const priority = baseCounterPriority + (defensiveness * 1.5) + 
                   (opportunity.allowsBreaking ? 2 : 0) +
                   (opportunity.vulnerabilityMultiplier > 2.0 ? 1 : 0);
  
  if (priority >= decisionThreshold) {
    selectCounterTechnique(opportunity.exposedLimb);
  }
}

Visual Indicators

LimbExposureIndicator3D (src/components/shared/three/effects/LimbExposureIndicator3D.tsx):

3D Glow Effect: Three.js pointLight attached to exposed limb position
Intensity Scaling: 1.0-3.0 based on vulnerability multiplier
Color Coding:
- Gold (#ffaa00): Low vulnerability (<1.5x)
- Orange (#ff6600): Medium vulnerability (1.5-2.0x)
- Red (#ff0000): High vulnerability / Breaking opportunity (≥2.0x)
Fade Animation: Smooth fade in/out during 300-400ms exposure window
Performance: <0.5ms overhead per frame, 60fps maintained

VulnerabilityWindowHUD (src/components/shared/three/ui/VulnerabilityWindowHUD.tsx):

Circular Timer: Progress ring showing remaining opportunity time
Bilingual Labels: "반격 기회" (Korean) / "Counter Opportunity" (English)
Urgency Colors:
- Early (0-50%): Gold (plenty of time)
- Mid (50-75%): Orange (closing window)
- Late (75-100%): Red (last moment)
Mobile Layout: Compact design, 70% scale on mobile devices

Type Extensions

PlayerState Extended:

interface PlayerState {
  // ... existing fields
  currentTechnique?: KoreanTechnique; // Technique being executed
  techniqueElapsedTime?: number; // Time elapsed in technique (ms)
}

CombatContext Extended:

interface CombatContext {
  // ... existing fields
  opponentTechnique?: KoreanTechnique;
  opponentTechniqueTime?: number;
  counterOpportunity?: CounterOpportunity;
  opponentVulnerability: number; // 1.0-2.5x multiplier
}

Implementation Example

// Detect limb exposure during attack
const opportunity = calculateCounterOpportunity(
  opponentTechnique,
  elapsedTime // 450ms into 800ms technique
);

if (opportunity) {
  console.log(opportunity);
  // {
  //   exposedLimb: "right_leg",
  //   vulnerabilityMultiplier: 2.0,
  //   allowsBreaking: true,
  //   recommendedCounters: ["ankle_stomp", "knee_kick"],
  //   remainingWindow: 350, // ms
  //   confidence: 0.85
  // }
}

Test Coverage

36 tests: LimbExposureSystem core functions
14 tests: Full attack-counter integration flow
15 tests: BreakingStatusEffects validation
18 tests: AI DecisionTree counter-attack integration
19 tests: LimbExposureIndicator3D visual component
30 tests: VulnerabilityWindowHUD UI component
Total: 132/132 tests passing (100%) ✅

Korean Martial Arts Philosophy

The system embodies traditional principles:

허점공격 (Heojeom Gonggyeok): Attacking openings/weaknesses
후수필승 (Husu Pilseung): Victory through counter-attack timing
이순응변 (Isun Eungbyeon): Adapt and exploit opponent's mistakes
파쇄기 (Paswaegi): Breaking techniques for overextended attacks

💡 Technical Specifications

Performance Requirements:

Target FPS: 60 FPS during intense combat
Memory Usage: < 512MB for full combat simulation
Audio Latency: < 100ms for responsive feedback
Input Lag: < 16ms for precise control

Cultural Authenticity Standards:

Korean Terminology: Bilingual Korean-English throughout
Martial Arts Accuracy: Traditional techniques with proper names
Philosophy Integration: I Ching principles in combat mechanics
Respectful Representation: Honor Korean martial arts heritage

Combat Realism Targets:

Anatomical Accuracy: 70 precise vital points
Damage Calculation: Physics-based trauma simulation
Status Effects: Pain, consciousness, balance, blood loss
Recovery Systems: Realistic healing and regeneration

🎯 Success Metrics

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graph LR
    subgraph "Combat Effectiveness Metrics"
        ACC[정확도 Accuracy<br/>85%+ hit detection]:::metric
        REA[사실성 Realism<br/>Authentic damage calc]:::metric
        CUL[문화성 Culture<br/>100% Korean terms]:::metric
        PER[성능 Performance<br/>60 FPS target]:::metric
    end

    classDef metric fill:#00ff00,stroke:#333,color:#000,stroke-width:2px

흑괘의 길을 걸어라 - Walk the Path of the Black Trigram

This architecture document reflects the current implementation state of Black Trigram's combat system as of the latest codebase analysis. All empty system files represent planned implementations following authentic Korean martial arts principles.