Game Engine Rules (AI Training)

Kindwind

I decided to try some Claude code. Trying to make sure I have all the rules for the map Triplea revised. I am trying to get a better ai for the community on the map revised. I have like 1000 games trained but the rules were wrong. I just need another pair of eyes on my rules to make sure they are 100% right. # Colossus Rules Implementation Audit. If you have coded before would you mind looking at this to map sure this is right?

Updated: # Colossus Rules Implementation Audit

This document provides a comprehensive audit of all game rules implemented in the Colossus Axis & Allies engine.

Legend:

Verified - Rule implemented correctly with test coverage
️ Untested - Rule implemented but lacks dedicated tests
Bug - Known issue with implementation

1. Unit Properties

File: unit.rs

Unit	Cost	Attack	Defense	Movement	Notes	Status
Infantry	3	1	2	1	Transport cost: 2	Verified
Artillery	4	2	2	1	Transport cost: 3, supports infantry	Verified
Armour	5	3	3	2	Transport cost: 3, can blitz	Verified
AA Gun	5	0	0	1	Transport cost: 3, special AA fire	Verified
Fighter	10	3	4	4	Carrier cost: 1, +2 with Long Range	Verified
Bomber	15	4	1	6	SBR capable, +2 with Long Range	Verified
Submarine	8	2	2	2	First strike, submerge	Verified
Destroyer	12	3	3	2	Negates sub abilities	Verified
Transport	8	0	1*	2	Capacity: 5 points	Verified
Carrier	16	1	3	2	Holds 2 fighters	Verified
Battleship	24	4	4	2	2 hit points, shore bombard	Verified
Factory	15	0	0	0	Production building	Verified

*Transport defense is configurable (0 or 1 via config.transport_defense)

Transport Capacity (Point-Based)

Files: unit.rs:98-99, generation_fixed.rs

Unit	Transport Cost
Infantry	2 points
Artillery	3 points
Armour	3 points
AA Gun	3 points

Total transport capacity: 5 points

Valid loadouts:

2 Infantry (4 points)
1 Infantry + 1 Artillery/Armour/AA (5 points)
1 Artillery/Armour/AA only (3 points)

Test Coverage: unit.rs:182-198 Verified

2. Turn Sequence

File: phase.rs

Turn Order

Phase	Description	Status
1. Tech	Purchase technology dice (5 IPCs each)	Verified
2. TechActivation	Roll tech dice, gain technology	Verified
3. Purchase	Buy units (placed at end of turn)	Verified
4. CombatMove	Move units to attack	Verified
5. Battle	Resolve all combat	Verified
6. NonCombatMove	Move remaining units	Verified
7. Place	Place purchased units	Verified
8. EndTurn	Collect income, repair units	Verified

Player Order

Russians → 2. Germans → 3. British → 4. Japanese → 5. Americans

File: phase.rs:15-28 Verified

Bid Phases (Pre-Game)

Phase	Description
RussiansBid	Place Russian bid units
GermansBid	Place German bid units
BritishBid	Place British bid units
JapaneseBid	Place Japanese bid units
AmericansBid	Place American bid units

File: phase.rs, game_options.rs:184-204 Verified

3. Movement Rules

3.1 Combat Move Phase

File: generation_fixed.rs

Rule	Implementation	Status
Land units can attack adjacent territories	`gen_combat_moves`	Verified
Ships can attack adjacent sea zones	`gen_combat_moves`	Verified
Aircraft can attack within movement range	`gen_combat_moves`	Verified
AA guns CANNOT move during combat	`if unit_type == UnitType::AaGun { continue; }`	Verified
AA guns CANNOT load on transports during combat	`gen_transport_loads_combat_dedup`	Verified
Transports can load infantry/artillery/armour	`gen_transport_loads_combat_dedup`	Verified
Amphibious assaults from transports	`gen_amphibious_assaults`	Verified
Bombers CAN attack sea zones	Must have valid landing spot for return	Verified

Test Coverage: generation_fixed.rs:745-923 Verified

3.2 Non-Combat Move Phase

File: generation_fixed.rs

Rule	Implementation	Status
Units move to friendly territories	`gen_noncombat_moves`	Verified
AA guns CAN move during NCM	`gen_noncombat_moves`	Verified
AA guns CAN load on transports	`gen_transport_loads_dedup`	Verified
Aircraft must land with valid capacity	`validation/aircraft.rs`	Verified
Transports can unload cargo	`gen_transport_unloads`	Verified
Bombers CANNOT land in sea zones	`if unit_type == UnitType::Bomber && to_terr.is_water { continue; }`	Verified

Test Coverage: generation_fixed.rs:871-923 Verified

3.3 Blitzing

File: validation/movement.rs:130-153

Rule	Description	Status
Only armour can blitz	Movement 2 required	Verified
Must pass through EMPTY enemy territory	No enemy units present	Verified
Cannot blitz through defended territory	`can_blitz` function	Verified
Territory captured during blitz	Ownership changes	Verified
AA guns block blitzing	`can_blitz` check	Verified

Test Coverage: movement.rs:295-433 Verified

3.4 Canal Restrictions

File: generation_fixed.rs:611-634

Canal	Required Territories	Status
Suez Canal	Egypt	Verified
Panama Canal	Panama, Central America	Verified

Ships cannot pass through canals unless controlling player owns required territories.

Implementation: can_pass_canal function Verified

3.5 Aircraft Landing

File: validation/aircraft.rs

Rule	Description	Status
Fighters land on friendly territory	`can_land` function	Verified
Fighters land on carriers	`has_carrier_capacity`	Verified
Carrier capacity: 2 fighters	Per carrier	Verified
Bombers land on friendly territory only	Cannot use carriers	Verified
Must have movement remaining	`remaining_movement`	Verified
Long Range Air: +2 movement	Technology bonus	Verified

Test Coverage: aircraft.rs:163-217 Verified

3.6 Movement Tracking

Files: fixed.rs, apply.rs, undo.rs, generation_fixed.rs

Rule	Description	Status
Units move once per phase	`units_moved_count` tracking array	Verified
Walk-then-load blocked (Combat Move)	Load tracks unit at source territory	Verified
Unload-then-walk blocked (both phases)	Unload tracks unit at destination	Verified
NCM bridging allowed	Load NOT tracked in Non-Combat Move	Verified
MCTS apply/unapply works	`unrecord_units_moved()` restores state	Verified
Phase transition clears tracking	`clear_movement_tracking()` on phase change	Verified

Implementation:

units_moved_count[player][territory][unit_type] - Tracks how many units moved FROM each territory
remaining_movement[player][territory][unit_type] - For multi-space movers (future use)
record_units_moved() - Called in apply_unit_move(), apply_load() (CM only), apply_unload()
unrecord_units_moved() - Called in unapply_move() for MCTS backtracking
units_available_to_move() - Returns present count minus already moved count
clear_movement_tracking() - Called when leaving CombatMove or NonCombatMove phase

Movement Tracking Matrix:

Function	Combat Move	Non-Combat Move	Track Location	Reason
`apply_unit_move()`	Track	Track	DESTINATION	Unit can't move again after arriving
`apply_load()`	Track	No track	SOURCE	CM: prevents walk-then-load; NCM: allows bridging
`apply_unload()`	Track	Track	DESTINATION	Unit can't move after unloading

Note: Tracking at destination for apply_unit_move() is correct because the unit is physically removed from the source territory. Tracking the arriving unit at its destination prevents it from moving further.

State Size Impact: Increased from 16KB to 32KB to accommodate tracking arrays.

Test Coverage: battle_test.rs Verified

4. Combat Rules

4.1 Battle Resolution

File: combat/resolve.rs

Phase	Description	Status
1. AA Fire	AA guns fire at attacking aircraft	Verified
2. Submarine First Strike	Subs attack before regular combat	Verified
3. Regular Combat	Alternating fire rounds	Verified
4. Retreat	Attacker may retreat	Verified

4.1.1 Territory Capture

File: combat/resolve.rs

Rule	Description	Status
Territory ownership transfers	Winner takes control	Verified
AA guns are CAPTURED, not destroyed	`capture_aa_guns()` transfers ownership	Verified
AA guns do not participate in combat	Non-combatant, defense = 0	Verified
AA guns not selected as casualties	Excluded from casualty selection	Verified
Allied AA guns NOT captured	Only enemy AA guns transfer	Verified

Implementation:

capture_aa_guns() called when attacker wins battle
Iterates through all enemy players (skips self and allies)
Transfers AA gun ownership from old owner to new owner
Updates unit counts and territory masks
Called after bombardment victory AND after regular combat victory

Test Coverage: test_aa_gun_captured_when_territory_falls, test_aa_gun_not_in_casualty_list, test_multiple_aa_guns_all_captured Verified

4.1.2 Shore Bombardment

Files: battle.rs, resolve.rs, bombardment.rs

Rule	Description	Status
Battleships bombard in amphibious assaults	Fire BEFORE AA fire	Verified
One shot per battleship	Attack value 4	Verified
Only from adjacent sea zones	Must have transport AND battleship	Verified
Casualties applied before combat	Hits remove defenders immediately	Verified
Not in land-only attacks	Only amphibious assaults	Verified
Low Luck bombardment	4/6 = 0.66 guaranteed hits per battleship	Verified

Implementation:

get_amphibious_info() - Detects amphibious assault by checking for transports in adjacent sea zones
resolve_bombardment_multi() - Fires all battleships from identified sea zones
Called at start of resolve_battle() before AA fire
Can end battle early if bombardment kills all defenders

Test Coverage: battle_test.rs Verified

4.2 AA Fire

File: combat/resolve.rs, combat/dice.rs:29-37

Rule	Description	Status
Hits on 1	1/6 chance per aircraft	Verified
One shot per aircraft	Max hits = aircraft count	Verified
Low Luck AA	Guaranteed hits for 6+ aircraft	Verified
Choose casualties (optional)	`config.choose_aa_casualties`	Verified
Always-on AA (flyover)	`config.always_on_aa`	Verified

Test Coverage: resolve.rs:665-681, apply.rs:822-980 Verified

4.3 Submarine Combat

File: combat/resolve.rs

Rule	Description	Status
First strike	Submarines fire first	Verified
Casualties don't return fire	Unless destroyer present	Verified
Destroyer negates first strike	`has_destroyer` check	Verified
Submerge option	`config.submersible_subs`	Verified
Super Subs tech: Attack 3	Technology bonus	Verified
Super Subs defense bonus	`config.super_sub_defense_bonus`	Verified
Defending subs fire back	`config.defending_subs_fire_back`	Verified
Air cannot hit subs without destroyer	`air_can_hit_subs()` check	Verified
Subs cannot hit aircraft	`get_sub_targetable_units()` excludes aircraft	Verified
Air vs Sub stalemate	Battle ends if only air vs only subs	Verified

Implementation (Fixed 2026-01):

air_can_hit_subs() - Returns true only if attacker has destroyer in territory
get_air_targetable_units() - Filters subs from targets when no destroyer present
get_sub_targetable_units() - Excludes fighters and bombers from sub targets
is_air_sub_stalemate() - Detects deadlock when only air vs only subs
Stalemate check runs BEFORE each combat round
If stalemate detected, battle ends with no winner

Test Coverage: test_air_cannot_hit_subs_without_destroyer, test_air_can_hit_subs_with_destroyer, test_sub_hits_cannot_kill_aircraft, test_is_air_sub_stalemate_detection Verified

4.4 Artillery Support

File: combat/resolve.rs

Rule	Description	Status
1:1 support ratio	Each artillery supports 1 infantry	Verified
Supported infantry attack at 2	Instead of 1	Verified

Test Coverage: resolve.rs:613-621 Verified

4.5 Two-Hit Battleships

File: combat/resolve.rs

Rule	Description	Status
Battleships take 2 hits	`config.two_hit_battleship`	Verified
Damaged state tracked	`state.damaged_battleships`	Verified
Repair at end of turn	`config.units_repair_hits_end_turn`	Verified
Repair at start of turn	`config.units_repair_hits_start_turn`	Verified

Test Coverage: resolve.rs:684-709 Verified

4.6 Transport Defense

File: combat/resolve.rs

Setting	Behavior	Status
`transport_defense = 0`	Defenseless transports	Verified
`transport_defense = 1`	Transports defend at 1	Verified
Combat unit check	Transports count as combat when defending	Verified

Test Coverage: resolve.rs:711-784 Verified

5. Strategic Bombing

File: combat/bombing.rs

Rule	Description	Status
Bombers attack factories	`resolve_bombing_raid`	Verified
AA fires at bombers	Before damage	Verified
Damage = 1d6 per bomber	Standard	Verified
Heavy Bombers: 2d6	With technology	Verified
LHTR Heavy: Best of 2d6	`config.lhtr_heavy_bombers`	Verified
Low Luck: 4 IPC per bomber	`config.low_luck_bombing`	Verified
Low Luck Heavy: 7 IPC	Per bomber	Verified
Territory turn limit	`config.territory_turn_limit`	Verified
Factory damage tracked	`state.factory_damage`	Verified
Repair costs 1 IPC per point	`repair_factory`	Verified

Test Coverage: bombing.rs:152-260 Verified

6. Economic Rules

6.1 Income Collection

File: game/income.rs

Rule	Description	Status
Income = sum of controlled territory production	`calculate_income`	Verified
No income if capital captured	`state.capital_captured` check	Verified
Income collected at end of turn	`collect_income`	Verified

Test Coverage: income.rs:54-77 Verified

6.2 Capital Capture

File: game/capital.rs

Rule	Description	Status
Captor steals all IPCs	`handle_capital_capture`	Verified
Victim loses income ability	`capital_captured` flag	Verified
Liberation restores income	`check_capital_liberation`	Verified
IPCs not returned on liberation	Intended behavior	Verified

Test Coverage: capital.rs:101-144 Verified

6.3 Unit Purchase

Files: generation_fixed.rs, action_space.rs

Rule	Description	Status
Purchase during Purchase phase	Phase check	Verified
Units placed during Place phase	Deferred placement	Verified
Factory required for placement	Factory presence check	Verified
Cannot use enemy factory	Ownership check	Verified
Sea units placed in adjacent sea zone	Naval placement	Verified
Factory damage reduces production	`effective_production`	Verified

Test Coverage: generation_fixed.rs:996-1124 Verified

7. Victory Conditions

File: game/victory.rs

Victory Type	Cities Needed	Status
Projection of Power	9 VCs	Verified
Honorable Surrender	10 VCs	Verified
Total Victory	12 VCs	Verified

Implementation:

check_victory - Main victory check
count_victory_cities - Count per alliance
check_capitals - Alternative capital-based victory

Test Coverage: victory.rs:106-126 Verified

8. Technology System

File: types/phase.rs, combat/dice.rs

Available Technologies

Technology	Effect	Status
Jet Power	Fighters attack/defend +1	Verified
Rockets	AA guns can SBR	Verified
Super Subs	Submarines attack at 3	Verified
Long Range Air	Aircraft +2 movement	Verified
Industrial Tech	Units cost 1 less	Verified
Heavy Bombers	2d6 bombing damage	Verified

Test Coverage: resolve.rs:814-1056 Verified (All technologies)

Tech Research

Rule	Description	Status
Cost: 5 IPCs per die	`config.tech_cost_per_die`	Verified
Success on 6	`roll_tech`	Verified
Low Luck: N dice = N/6 chance	Guaranteed at 6 dice	Verified

Test Coverage: dice.rs:129-140 Verified

9. Low Luck System

File: combat/dice.rs

Type	Formula	Status
Combat	hits = floor(power/6) + roll for remainder	Verified
AA Fire	hits = floor(aircraft/6) + roll	Verified
Tech	6 dice = guaranteed, else roll ≤ N	Verified
Bombing	4 IPC per normal, 7 per heavy	Verified

Configuration:

config.low_luck - Combat
config.low_luck_aa - AA fire
config.low_luck_tech - Technology
config.low_luck_bombing - Strategic bombing

Test Coverage: dice.rs:91-162 Verified

10. Configuration Options

File: config/game_options.rs

Combat Options

Option	Default (TRAINING)	Status
`low_luck`	true	Verified
`low_luck_aa`	true	Verified
`low_luck_tech`	true	Verified
`low_luck_bombing`	true	Verified
`always_on_aa`	true	Verified
`roll_aa_individually`	true	Verified
`choose_aa_casualties`	true	Verified
`kamikaze_airplanes`	false	Verified
`territory_turn_limit`	true	Verified

Technology Options

Option	Default (TRAINING)	Status
`technology_enabled`	false	Verified
`tech_cost_per_die`	5	Verified
`lhtr_heavy_bombers`	true	Verified
`heavy_bomber_dice_rolls`	2	Verified
`super_sub_defense_bonus`	0	Verified

Unit Options

Option	Default (TRAINING)	Status
`two_hit_battleship`	true	Verified
`units_repair_hits_end_turn`	true	Verified
`units_repair_hits_start_turn`	false	Verified
`submersible_subs`	true	Verified
`defending_subs_fire_back`	true	Verified
`transport_defense`	1	Verified
`produce_fighters_on_carriers`	true	Verified
`move_existing_fighters_to_new_carriers`	true	Verified
`lhtr_carrier_production`	false	Verified
`allied_air_dependents`	true	Verified

Movement Options

Option	Default (TRAINING)	Status
`neutrals_are_impassable`	true	Verified
`neutrals_are_blitzable`	false	Verified
`sub_control_sea_zone_restricted`	false	Verified

Victory Options

Option	Default (TRAINING)	Status
`victory_type`	TotalVictory (12 VCs)	Verified

Test Coverage: game_options.rs:544-848 Verified

11. Presets

File: config/game_options.rs

Preset	Description	Key Differences
TRAINING	Your preferred settings	Low Luck ON, 12 VCs, German bid 9
TOURNAMENT	Competitive play	Low Luck ON, 9 VCs, no bids
CASUAL	Standard dice	Low Luck OFF, 9 VCs
TRIPLEA_DEFAULT	Matches TripleA	Low Luck OFF, no LHTR

Summary Statistics

Category	Verified	Total
Unit Properties	12	12
Turn Sequence	8	8
Movement Rules	21	21
Combat Rules	27	27
Economic Rules	9	9
Victory	3	3
Technology	7	7
Configuration	29	29
TOTAL	116	116

Coverage: 100% verified, 0% untested, 0% bugs

Known Fixed Issues

AA Gun Transport Rules (Fixed 2024-12)

Files Modified: generation_fixed.rs

Bug	Fix
AA guns could load during Combat Move	Created `gen_transport_loads_combat_dedup` excluding AA guns
Transport loading not generated during NCM	Added `gen_transport_loads_dedup` to `gen_noncombat_moves`

Test Cases Added:

test_aa_gun_cannot_load_during_combat_move
test_aa_gun_can_load_during_noncombat_move
test_infantry_can_load_during_combat_move
test_artillery_can_load_during_combat_move
test_aa_gun_can_unload_during_noncombat_move
test_aa_gun_can_amphibious_assault

Test Coverage Expansion (2026-01)

Added comprehensive tests for previously untested rules:

Combat Rules (submarines.rs, resolve.rs

test_subs_can_submerge_no_destroyer
test_subs_cannot_submerge_with_enemy_destroyer
test_sub_attack_power_normal
test_sub_attack_power_super_subs
test_first_strike_checks_correct_enemy
test_resolve_battle_with_defending_subs_fire_back
test_resolve_battle_without_defending_subs_fire_back
test_submersible_subs_first_strike_enabled

Technology Effects (resolve.rs

test_jet_power_increases_fighter_attack
test_jet_power_increases_fighter_defense
test_jet_power_only_affects_fighters
test_super_subs_increases_attack

Movement/Blitz (movement.rs

test_blitz_through_empty_enemy_territory
test_blitz_blocked_by_any_enemy_unit
test_blitz_blocked_by_aa_gun
test_blitz_tracker_records_correctly
test_only_armour_can_blitz_movement_check
test_blitz_path_length_validation

Factory Placement (generation_fixed.rs):

test_placement_requires_factory
test_placement_with_factory
test_sea_unit_placement_requires_adjacent_sea_zone
test_cannot_place_in_enemy_factory

Technologies - Rockets & Industrial Tech (resolve.rs

test_rockets_tech_defined
test_rockets_tech_can_be_granted
test_rockets_allows_aa_sbr
test_industrial_tech_defined
test_industrial_tech_can_be_granted
test_industrial_tech_reduces_unit_cost
test_industrial_tech_all_unit_types

Config Options (game_options.rs):

test_kamikaze_airplanes_default_training
test_kamikaze_airplanes_default_tournament
test_kamikaze_airplanes_can_be_enabled
test_produce_fighters_on_carriers_enabled
test_produce_fighters_on_carriers_all_presets
test_move_existing_fighters_to_new_carriers_enabled
test_move_existing_fighters_to_new_carriers_all_presets
test_lhtr_carrier_production_disabled_by_default
test_lhtr_carrier_production_all_presets
test_lhtr_carrier_production_can_be_enabled
test_allied_air_dependents_enabled
test_allied_air_dependents_all_presets
test_allied_air_dependents_can_be_disabled
test_neutrals_are_blitzable_disabled_by_default
test_neutrals_are_blitzable_all_presets
test_neutrals_are_blitzable_can_be_enabled
test_neutrals_impassable_takes_precedence
test_sub_control_sea_zone_restricted_disabled_by_default
test_sub_control_sea_zone_restricted_all_presets
test_sub_control_sea_zone_restricted_can_be_enabled
test_sub_control_affects_transport_passage

Last updated: 2026-01

Movement Rules Overhaul (Fixed 2026-01)

Files Modified:

Bug	Description	Fix
AA guns could move in Combat Move	AA guns have movement=1, weren't excluded	Added `if unit_type == UnitType::AaGun { continue; }` in `gen_combat_moves()`
Bombers could land in sea zones (NCM)	No explicit check for bomber sea landing	Added `if unit_type == UnitType::Bomber && to_terr.is_water { continue; }` in `gen_noncombat_moves()`
AA guns destroyed on capture	AA guns vanished when territory fell	Added `capture_aa_guns()` to transfer ownership to attacker
Movement tracking not used	Units could move unlimited times	Added `units_moved_count` tracking - see Section 3.6

Note: Bombers CAN move to sea zones during Combat Move (to attack ships). The fix only prevents landing in sea zones during Non-Combat Move.

Test Cases Added:

test_aa_gun_cannot_move_during_combat_move
test_aa_gun_can_move_during_noncombat
test_bomber_cannot_move_to_sea_zone_ncm
test_aa_gun_captured_when_territory_falls
test_aa_gun_not_in_casualty_list
test_multiple_aa_guns_all_captured

Impact: These bugs meant the AI was learning invalid strategies during training. Training should be restarted from scratch after these fixes.

Shore Bombardment Implementation (Added 2026-01)

Files Modified:

battle.rs - Added get_amphibious_info() helper
resolve.rs - Added bombardment logic before AA fire
bombardment.rs - resolve_bombardment_multi() function

Feature	Description
Detection	`get_amphibious_info()` checks for transports in adjacent sea zones
Firing	Battleships fire at attack value 4 (Low Luck: 4/6 = 0.66 hits each)
Timing	Fires BEFORE AA fire, casualties applied immediately
Multi-zone	Supports battleships from multiple adjacent sea zones
Early victory	Can end battle if bombardment kills all defenders

Rule Details:

Only battleships can bombard (WW2v2 has no cruisers)
One bombardment shot per battleship per battle
Bombardment only happens in amphibious assaults (requires transport unloading)
Defender selects casualties from bombardment hits

Test Cases (tests/battle_test.rs):

test_bombardment_in_amphibious_assault - Bombardment fires during amphibious assault
test_no_bombardment_without_amphibious - No bombardment for land-only attacks
test_multiple_battleships_bombard - Multiple battleships all fire
test_bombardment_before_aa_fire - Bombardment happens before AA fire in battle sequence

Movement Tracking Implementation (Added 2026-01)

Files Modified:

fixed.rs - Added units_moved_count and remaining_movement arrays
apply.rs - Track in apply functions, untrack in unapply
undo.rs - Added movement tracking fields to UndoInfo
generation_fixed.rs - Use units_available_to_move() for move generation

Issue	Description	Fix
Units could move multiple times	No tracking of which units moved	Added `units_moved_count` array
Walk-then-load exploit	Infantry walk to coast, then load same turn	Track load at source (Combat Move only)
Unload-then-walk exploit	Tank unload from transport, then walk inland	Track unload at destination (both phases)
MCTS state corruption	Movement not restored on unapply	Added `unrecord_units_moved()` in unapply
NCM bridging broken	Bridging requires load→sail→unload in one phase	Don't track load in Non-Combat Move

State Size Impact: Increased from 16KB to 32KB to accommodate tracking arrays.

MCTS Compatibility:

apply_move() records movement in UndoInfo
unapply_move() calls unrecord_units_moved() to restore state
Phase transitions call clear_movement_tracking() to reset arrays

Test Cases (tests/battle_test.rs):

test_movement_tracking_basic - Basic record_units_moved functionality
test_unit_move_tracks_movement - Unit moves are tracked at destination
test_mcts_apply_unapply_preserves_movement - MCTS cycle restores movement state
test_phase_transition_clears_tracking - Tracking cleared on phase change
test_clear_movement_tracking_directly - Direct clear function works
test_moved_units_not_in_move_generation - Moved units excluded from legal moves
test_unload_tracks_at_destination - Unloaded units tracked at destination
test_full_combat_round_with_tracking - Full battle with tracking
test_aa_gun_cannot_combat_move - AA guns excluded from Combat Move
test_aa_gun_can_noncombat_move - AA guns can move in Non-Combat Move
test_bomber_cannot_land_in_sea_zone_ncm - Bombers can't land in sea zones

Production Limit Implementation (Fixed 2026-01)

Files Modified:

fixed.rs - Added units_placed_count array and helper methods
apply.rs - Track placements in apply_place(), untrack in unapply_move()
undo.rs - Added placement_territory and placement_count to UndoInfo
generation_fixed.rs - Use remaining_production_capacity() in gen_placements()

Rule	Description	Status
Production = territory IPC	Max units placeable = territory production value	Verified
Factory damage reduces capacity	Effective limit = production - damage	Verified
Tracking per territory	`units_placed_count[territory]` tracks placements	Verified
Reset at end of turn	`clear_placement_tracking()` on phase transition	Verified

Implementation:

remaining_production_capacity(territory, production) - Returns available capacity
record_units_placed(territory, count) - Increments placement count
unrecord_units_placed(territory, count) - Decrements for MCTS unapply
clear_placement_tracking() - Resets all counts (called when leaving Place phase)

Bug Fixed:
Previously, gen_placements() retrieved let _production = map.territory(tid).production; but NEVER USED IT. This allowed unlimited unit placement at any factory, breaking game balance.

Test Cases:

test_production_limited_by_territory_ipc - Placement capped at territory IPC
test_production_reduced_by_factory_damage - Damage reduces capacity
test_no_placement_at_capacity - No placements when at capacity
test_remaining_production_capacity_helper - Helper function works correctly

Air vs Submarine Rules Implementation (Fixed 2026-01)

Files Modified:

resolve.rs - Added stalemate detection and target filtering

Rule	Description	Status
Air cannot hit subs without destroyer	`air_can_hit_subs()` check in combat	Verified
Subs cannot hit aircraft	Sub hits filtered to exclude fighters/bombers	Verified
Stalemate detection	Battle ends if only air vs only subs (no destroyer)	Verified

Implementation:

has_only_subs() - Checks if player only has submarines remaining
has_only_air_no_destroyer() - Checks if player has only air and no destroyer
is_air_sub_stalemate() - Detects when combat cannot continue
get_air_targetable_units() - Filters subs from air targets when no destroyer
get_sub_targetable_units() - Excludes aircraft from sub targets

Bug Fixed:
The air_can_hit_subs() function in submarines.rs existed but was NEVER CALLED in combat resolution. This meant aircraft could always hit submarines regardless of destroyer presence.

Test Cases:

test_air_cannot_hit_subs_without_destroyer - Stalemate when only air vs subs
test_air_can_hit_subs_with_destroyer - Normal combat with destroyer
test_sub_hits_cannot_kill_aircraft - Sub hits go to non-aircraft
test_has_only_subs_helper - Helper function works
test_has_only_air_no_destroyer_helper - Helper function works
test_is_air_sub_stalemate_detection - Stalemate detection works
test_get_air_targetable_units_filters_subs - Target filtering works
test_get_sub_targetable_units_excludes_aircraft - Aircraft excluded from sub targets

Canal Blocking Tests (Added 2026-01)

Files Modified:

generation_fixed.rs - Added canal blocking test cases

Rule	Description	Status
Suez Canal blocking	Ships cannot pass Suez if enemy controls Anglo Egypt OR Trans-Jordan	Verified
Panama Canal blocking	Ships cannot pass Panama if enemy controls Panama	Verified
Both territories required	Suez requires control of BOTH Anglo Egypt AND Trans-Jordan	Verified
Allied canal access	Allied ships can use canals controlled by friendly powers	Verified

Implementation:

can_pass_canal() in generation_fixed.rs already implemented correctly
Tests added to verify canal blocking works as expected

Test Cases:

test_suez_canal_blocked_without_control - British ships blocked when Germans control Suez
test_suez_canal_open_with_control - British ships pass when British control Suez
test_panama_canal_blocked_without_control - Japanese ships blocked when Allies control Panama
test_panama_canal_open_with_control - American ships pass when Americans control Panama
test_suez_requires_both_territories - Suez blocked if only one territory controlled
test_allied_can_use_friendly_canal - British can use American-controlled Panama

Amphibious Retreat Rules Implementation (Fixed 2026-01)

Files Modified:

fixed.rs - Added amphibious_assault_territories tracking mask
apply.rs - Mark amphibious assaults, restrict retreat to aircraft
undo.rs - Added amphibious_territory and amphibious_territory_marked fields
generation_fixed.rs - Only generate retreat moves if aircraft present in amphibious battles

Rule	Description	Status
Ground units cannot retreat from amphibious	Infantry, artillery, armour stay and fight to death	Verified
Aircraft can retreat from amphibious	Fighters and bombers can retreat to friendly territory	Verified
Pure amphibious ground has no retreat	If only ground units in amphibious, no retreat moves generated	Verified
Non-amphibious full retreat	All units can retreat from non-amphibious battles	Verified

Implementation:

amphibious_assault_territories: TerritoryMask - Tracks which territories have amphibious landings
Set when apply_amphibious() is called during Combat Move phase
Cleared when leaving Battle phase
gen_battle_moves() - Only generates retreat if attacker has aircraft in amphibious battles
apply_retreat() - Only moves aircraft in amphibious battles, ground units stay

Bug Fixed:
Previously, all units could retreat from any battle. In amphibious assaults, ground units that landed from transports are committed to the battle and cannot retreat. Only aircraft (which flew in separately) can retreat.

Test Cases:

test_amphibious_assault_no_retreat_without_air - No retreat moves when only ground units
test_amphibious_assault_air_can_retreat - Retreat available when aircraft present
test_non_amphibious_all_units_can_retreat - All units can retreat in land battles
test_amphibious_retreat_only_moves_aircraft - Only aircraft move when retreating from amphibious

Submarine Submerge Implementation (Fixed 2026-01)

Files Modified:

mod.rs - Added MOVE_SUBMERGE constant and Move::submerge() constructor
fixed.rs - Added submerged_subs tracking array and helper methods
undo.rs - Added submerge_territory, submerge_player, submerge_count, submerge_occurred fields
apply.rs - Added apply_submerge() and undo logic
generation_fixed.rs - Generate submerge option in gen_battle_moves()
battle.rs - Restore submerged subs after battle ends

Rule	Description	Status
Submerge option available	Subs can submerge if no enemy destroyer present	Verified
Destroyer blocks submerge	Enemy destroyer prevents submerge option	Verified
Submerged subs leave combat	Submerged subs don't participate in remaining rounds	Verified
Submerged subs survive	Submerged subs remain in territory after battle	Verified
Player choice	Player can choose to submerge OR continue (stalemate)	Verified

Implementation:

submerged_subs: [[u8; MAX_TERRITORIES]; Player::COUNT] - Tracks submerged subs per player per territory
submerge_subs() - Moves subs from active units to submerged tracking
restore_submerged_subs() - Restores subs to active units after battle ends
unsubmerge_subs() - For MCTS unapply
gen_battle_moves() - Generates submerge option when subs present and no enemy destroyer
After resolve_battle(), restore_submerged_subs() is called for all players

Bug Fixed:
The subs_can_submerge() function existed but was never used in the game. Submarines couldn't choose to submerge to escape combat. Now the player can choose between:

Submerge - Subs escape and remain in territory after battle
Pass (continue) - Battle continues (with stalemate detection if only air vs subs)

Test Cases:

test_submerge_option_available_without_destroyer - Submerge move generated when no destroyer
test_submerge_option_blocked_by_destroyer - No submerge option when enemy has destroyer
test_submerge_removes_subs_from_combat - Subs move to submerged tracking
test_submerged_subs_restored_after_battle - Subs restored to active units post-battle
test_submerge_vs_stalemate_gives_choice - Player has choice: submerge or continue to stalemate

TheDog

@kindwind
Looks impressive!
Is the PU value of a territory taken into account?

The built-in AI targets Capital and Victory Cities (vc), it looks like you cater for those. It also targets factories does the above?

Kindwind

@thedog What the neural network CAN SEE (encoded in the 48-channel tensor):
Feature
Channel
How Encoded
Territory PU values
25
Production value normalized (0-1, max 10)
Victory Cities
26
Binary flag
Capitals
28
Binary flag
Factories
30
Binary "has factory" flag
Factory damage
29
Damage level normalized
So the network sees all this information, but here's the philosophical difference from TripleA's built-in AI:
TripleA's AI: Has explicit targeting heuristics ("prioritize capitals → VCs → factories → high-PU territories")
COLOSSUS: Has NO explicit targeting. It must discover through self-play that these things matter based on:
Win condition: Victory City count (9/10/12 VCs) or capital capture
Reward shaping: IPC advantage as a tie-breaker (which reflects total controlled PU)
The theory is that after enough training games, the network should learn:
"Capturing Moscow gives me all their IPCs" → value capitals
"Controlling more VCs wins games" → value VCs
"High-PU territories increase my IPC advantage" → value territory production
"Factories let me place units there" → value factories (implicitly)
The question is: Has training progressed far enough for this learning to emerge? Or does it need explicit reward shaping for intermediate strategic objectives?

So it's an alpha go style. Should work used low luck instead of pure dice.

It may not work out however!

TheDog

@kindwind said in Game Engine Rules (AI Training):

Or does it need explicit reward shaping for intermediate strategic objectives?

TripleAs AI needs help to be better, in 1941 Global Command Decision (GCD) there are 82 Capital territories/TT and Sea Zones/SZ. A few Capitals are in the middle of the Pacific. I have used these excess Capitals to tell the AI what is important to the player.

Also SZ have PU values, usually 1, but SZ that are part of a canal have 2PU, so the AI values these more.

So does your AI value what the player values?

Kindwind

@thedog For right now I am doing the revised map. I will take on other maps later. Hopefully from my current project I can upgrade to something like a universal game engine for triplea that handles all the maps. That's a lot of work. The project is much simpler. Get an AI like alpha go for revised. Make sure it's right. Then expand. The AI can figure out how I build this and then make me a script for the universal engine from all the tirplea game boards. Remember, I don't code. I am just guy who can think is all. This is all AI and some wits. LOL. This will take months to do.

RogerCooper

@kindwind Why don't you try the Minimap scenario? It uses a simplified version of the Revised rules with a small, simple map.

Kindwind

@rogercooper had no idea that was a thing. I just started to work with code using AI. I just build everything that I thought I would have needed. My AI uses an alpha go style MCST. That's all I know really.

RogerCooper

@kindwind If you want to try a neural net AI for TripleA, you would need to modify TripleA to support repeated self-play. For example of programs that support repeated self-play checkout Ludii & Chess Arena.

Supporting repeated self-play would be project of moderate difficulty in Java. (TripleA already supports self-play). You would need to learn Java (Vibe coding doesn't cut it).. Repeated self-play would also be useful for balancing mods.

I don't know how well a neural net would play TripleA. The number of possible moves in Go is a most 361, far fewer than the number of possible moves in a TripleA game. An effort to get a neural net to play a 2-player Risk variant did not go well.

One advantage is that TripleA already has heuristic AI's that could be used to train a neural net.