1## Purpose2Document the shipped Shikaku built-in game behavior.34## Requirements56### Requirement: Registry Metadata7Shikaku SHALL be registered as a built-in game with canonical description "Divide the grid into rectangles with set sizes.", aliases `rectangles`, variants `Shikaku (default 1400 Elo)`, and daily legacy modes `easy 7x7, medium 8x8`.89#### Scenario: Resolve Shikaku10- **WHEN** the registry resolves the canonical name or any alias11- **THEN** it returns the Shikaku entry with help text, import behavior, variant metadata, and legacy mode compatibility1213### Requirement: Variant Elo Creation14Shikaku MUST support the current variant plus target Elo creation path, using the variant default Elo when no explicit target is supplied.1516#### Scenario: Spawn Shikaku by Elo17- **WHEN** the user selects the Shikaku variant and a target Elo from 0 through 300018- **THEN** PuzzleTea spawns a deterministic Shikaku puzzle and records target, actual, and confidence metadata when generation reports it1920### Requirement: Legacy Mode Compatibility21Shikaku SHALL preserve legacy named modes as compatibility presets that map to the Shikaku variant and preset Elo values: Mini 5x5 (300 Elo), Easy 7x7 (800 Elo), Medium 8x8 (1400 Elo), Hard 10x10 (2100 Elo), Expert 12x12 (2700 Elo).2223#### Scenario: Use legacy mode title24- **WHEN** the user supplies a legacy Shikaku mode title through CLI or deterministic daily metadata25- **THEN** PuzzleTea resolves it to the Shikaku variant and the registered preset Elo2627### Requirement: Puzzle Rules28The Shikaku runtime MUST let players partition the grid into rectangles, each rectangle containing exactly one clue and having area equal to that clue.2930#### Scenario: Check solved state31- **WHEN** the player fills the board or word state32- **THEN** Shikaku reports solved only when all rule constraints are satisfied3334### Requirement: Save Load And Interaction35Shikaku 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 rectangle editing is required, and mouse drag support MUST be available.3637#### Scenario: Resume saved Shikaku38- **WHEN** a saved Shikaku payload is imported39- **THEN** the restored game preserves givens, player entries, cursor/selection state where applicable, and solved-state behavior4041### Requirement: Print Export Support42The Shikaku print adapter SHALL render puzzle and solution data for JSONL-to-PDF workflows.4344#### Scenario: Export Shikaku45- **WHEN** Shikaku is included in a JSONL or PDF export flow46- **THEN** PuzzleTea follows the registered print support behavior for that game