Purpose

Document the shipped Takuzu built-in game behavior.

Requirements

Requirement: Registry Metadata

Takuzu SHALL be registered as a built-in game with canonical description "Fill the grid with filled and empty. No 3 in a row.", aliases binairo, binary, variants Takuzu (default 1600 Elo), and daily legacy modes medium, tricky.

Scenario: Resolve Takuzu

• WHEN the registry resolves the canonical name or any alias
• THEN it returns the Takuzu entry with help text, import behavior, variant metadata, and legacy mode compatibility

Requirement: Variant Elo Creation

Takuzu MUST support the current variant plus target Elo creation path, using the variant default Elo when no explicit target is supplied.

Scenario: Spawn Takuzu by Elo

• WHEN the user selects the Takuzu variant and a target Elo from 0 through 3000
• THEN PuzzleTea spawns a deterministic Takuzu puzzle and records target, actual, and confidence metadata when generation reports it

Requirement: Legacy Mode Compatibility

Takuzu SHALL preserve legacy named modes as compatibility presets that map to the Takuzu variant and preset Elo values: Beginner (300 Elo), Easy (700 Elo), Medium (1100 Elo), Tricky (1600 Elo), Hard (2100 Elo), Very Hard (2500 Elo), Extreme (2900 Elo).

Scenario: Use legacy mode title

• WHEN the user supplies a legacy Takuzu mode title through CLI or deterministic daily metadata
• THEN PuzzleTea resolves it to the Takuzu variant and the registered preset Elo

Requirement: Puzzle Rules

The Takuzu runtime MUST let players fill an even-sized grid with two symbols, avoid three identical symbols in a row or column, balance each row and column, and avoid duplicate completed rows or columns.

Scenario: Check solved state

• WHEN the player fills the board or word state
• THEN Takuzu reports solved only when all rule constraints are satisfied

Requirement: Save Load And Interaction

Takuzu SHALL serialize enough state for resume/import, reset to its initial puzzle, expose debug and full-help data, and support its shipped interaction model. Keyboard symbol entry is required, and mouse click-to-focus support MUST be available.

Scenario: Resume saved Takuzu

• WHEN a saved Takuzu payload is imported
• THEN the restored game preserves givens, player entries, cursor/selection state where applicable, and solved-state behavior

Requirement: Print Export Support

The Takuzu print adapter SHALL render puzzle and solution data for JSONL-to-PDF workflows.

Scenario: Export Takuzu

• WHEN Takuzu is included in a JSONL or PDF export flow
• THEN PuzzleTea follows the registered print support behavior for that game