Technical Details

This page summarizes game v1.4.0 and competitive rules spec v3.0 in player-readable form. Implementation-grade details live in the Phalanx Duel game repository.

Turn Sequence

Rules spec v3.0 executes a deterministic 8-phase lifecycle, including the optional DeploymentPhase. Attack declaration and combat resolution happen inside that lifecycle, not as a standalone loop.

flowchart LR A[StartTurn] --> B[DeploymentPhase optional] B --> C[AttackPhase] C --> D[AttackResolution] D --> E[CleanupPhase] E --> F[ReinforcementPhase] F --> G[DrawPhase] G --> H[EndTurn]

Gameplay Loop

The game alternates deterministic turns. Each turn emits events for all phases, even if no state changes occur.

flowchart TD S[Classic Setup
Draw 12, alternate deploy] --> T[Turn Trace] T --> U[8 Phase Execution] U --> V{Continue Match?} V -- Yes --> T V -- No --> X[Match Termination]

Statechart

State-level view of the canonical turn lifecycle.

stateDiagram-v2 [*] --> Setup Setup --> TurnStart TurnStart --> AttackPhase TurnStart --> DeploymentPhase: optional deployment DeploymentPhase --> AttackPhase AttackPhase --> AttackResolution AttackResolution --> CleanupPhase CleanupPhase --> ReinforcementPhase ReinforcementPhase --> DrawPhase DrawPhase --> EndTurn EndTurn --> TurnStart: next turn EndTurn --> GameOver: termination / forfeit / system error GameOver --> [*]

Suit Ability Timing

Suit effects are evaluated at boundaries during attack resolution. Canonical boundary order is Shield -> Weapon -> Clamp.

Suit	Role	Boundary	Canonical Trigger	Practical Effect
Diamonds	Shield	Card -> Card	If the current destroyed card is a Diamond and the next target is a card	Reduces carryover before the next defender takes damage
Hearts	Shield	Card -> Player	If the last destroyed card before the player is a Heart	Reduces final player damage (Hearts do not stack)
Clubs	Weapon	Card -> Card	If the attacker is Club and this is the first eligible boundary after the first destruction	Doubles carryover once per attack
Spades	Weapon	Card -> Player	If the attacker is Spade and carryover reaches the player	Doubles final player damage

Match Termination Signals (Canonical Concepts)

Player damage: Attack resolution can reduce player LP when carryover reaches the player boundary.
Pass limits: Exceeding consecutive or total pass limits results in forfeit.
System errors: Deterministic invariant violations terminate the match with an unrecoverable error event.
Important: Rules spec v3.0 uses deterministic draw/liveness semantics; empty draw pile alone is not an automatic loss.

Classic Special Cards

Classic Aces: A front-rank Ace is destroyable only by a direct Ace attack at target index 0.
Classic Face Cards: Jack/Queen/King destroy eligibility is rank-restricted (J < Q < K hierarchy).
Origin attacker is immutable: Destroy eligibility is determined by the original attacker across the full target chain.

Competitive Model (Glicko-2)

Ratings System: v1.4.0 includes the Glicko-2 matchmaking and ladder surface. (See Competitive Play)
Ranked Lobbies: Public matches contribute to a global leaderboard with volatility and rating deviation tracking.
Cross-Platform Rankings: Rankings are unified across Web, CLI (Go), and Mobile clients.

Combat Mathematics

For incoming damage d and target HP h, a normal card transition is absorbed = min(d, h), remainingHp = max(0, h - d), and carryover = max(0, d - h). Classic Ace and Face eligibility are explicit branches, not hidden randomness.

At a Card -> Card boundary, a destroyed Diamond subtracts its shield before an eligible Club doubles the remainder. At Card -> Player, the final destroyed Heart subtracts its shield before an attacking Spade doubles the remainder. All values clamp at zero.

The server records these integer operations as a schema-versioned witness. The same witness drives live events, previews, narration, replay, and the post-match Proof of Damage.

Observability & Verification

OTel Native: Full OpenTelemetry integration for distributed tracing of match lifecycles.
Ledger Persistence: Every match is backed by an append-only action ledger, allowing for full state rehydration and crash recovery.
Scientific Assurance: Rule evidence, mutation checks, liveness properties, replay equivalence, and observer noninterference qualify each correctness claim.
Combat Reference Proof: An implementation-independent model checks 2,355,388 declared finite cases with a pinned result digest.

Trust Model (Why This Matters Online)

Phalanx Duel uses a server-authoritative architecture in digital play.
The server validates actions against the rules engine.
Turns emit structured events and can be replay-verified with hashes.
Identical inputs must produce identical outputs under the same spec version.