Game Overview: This is an implementation of Axis & Allies Second Edition, a turn-based strategy game. The game features two teams (Allies and Axis) with 5 players:

• Allies: Russia (RUS), England (ENG), United States (USA)
• Axis: Germany (GER), Japan (JAP)

Turn Structure:

1. Air Phase:
   • Move unmoved fighters (for carrier landing options)
   • Move unmoved bombers
2. Naval Phase:
   • Move combat ships
   • Stage transports (pre-positioning)
3. Land Phase:
   • Move armies (including loading onto transports)
   • Move transports
   • Resolve sea battles
   • Unload transports
   • Resolve land battles
4. Cleanup Phase:
   • Move AA guns
   • Land remaining fighters
   • Land remaining bombers
   • Buy units
   • Buy factory
   • Reset units
   • Collect money
   • Rotate turns

Movement System:

1. Movement States:

   • UNMOVED: Unit has not been offered movement this turn
   • X_MOVES: Unit has X moves remaining (0, 1, or 2)
   • UNLOADED: (Transport specific) Declined to unload cargo
   • BOMBARDED: (Battleships/Cruisers) Used bombardment ability

2. Transport System: Capacity: 5 spaces total Unit Space Requirements:

   • Infantry (INF): 2 spaces
   • Artillery (ARTY): 3 spaces
   • Tank (TANK): 3 spaces
   • AA Gun: 6 spaces (exceeds capacity)

   Valid Configurations:

   • TRANS_EMPTY: No cargo
   • TRANS_1I: 1 Infantry
   • TRANS_1A: 1 Artillery
   • TRANS_1T: 1 Tank
   • TRANS_1I_1A: 1 Infantry + 1 Artillery
   • TRANS_1I_1A: 1 Infantry + 1 Tank
   • TRANS_2I: 2 Infantry

3. Transport Movement Sequence: a. Pre-staging Phase:

   • Transport starts as UNMOVED
   • Can move 0-2 spaces to position for loading
   • State changes to X_MOVES based on movement
   • Declining pre-stage sets to 2_MOVES b. Loading Phase:
   • Land units can load onto pre-staged transports
   • Loading allowed regardless of transport's moves c. Transport Movement Phase:
   • Transport moves with cargo d. Unloading Phase:
   • Transport unloads or declines (becomes UNLOADED)
   • No further movement or loading after unloading

Map Structure:

1. Movement Connections:

   • Land-to-Land (l2l): Direct land connections
   • Sea-to-Sea (s2s): Direct sea connections
   • Land-to-Sea (l2s): Where units can load/unload from transports
   • Air-to-Air (a2a): Air movement possibilities (X = 1-6)

2. Canals:

   • Connect specific sea zones
   • Require control of both connecting territories
   • Status tracked in canals_open bitset

State Management:

1. Game_State:

   • Core game state for save/load
   • Minimal required information

2. Game_Cache:

   • Derived data rebuilt from Game_State
   • Updated partially during turn rotation
   • No duplicate data with Game_State

3. Unit Tracking:

   • Active units: Belong to current player, includes movement state
   • Idle units: All other players' units, no movement tracking needed

Combat System:

1. Naval Combat:

   • Transports are vulnerable and have no combat power
   • Must be protected by combat ships

2. Bombardment:

   • Battleships and Cruisers: one bombardment per turn
   • State tracked via _BOMBARDED suffix

3. AA Defense:

   • Roll before regular combat
   • 1 die per plane (max 3 dice per AA gun)

AI Implementation:

• Uses Monte Carlo Tree Search (MCTS)
• Evaluates possible game states
• Provides move recommendations
• Performance optimized through Game_Cache structure