Hitori

Shade cells to eliminate duplicate numbers in every row and column.

How to Play

The grid starts filled with numbers. Shade some cells black so that three rules are satisfied:

1. No duplicates: No number appears more than once in any row or column among the unshaded (white) cells.
2. No adjacent shading: No two shaded cells share an edge (diagonal is fine).
3. White connectivity: All unshaded cells must form a single orthogonally connected region.

The puzzle is solved when all three rules hold simultaneously.

Controls

Key	Action
Arrow keys / WASD / hjkl	Move cursor
Mouse left-click	Focus a cell
x	Shade cell (toggle)
z	Circle cell as confirmed white (toggle)
Backspace	Clear cell to unmarked
Ctrl+H	Toggle full help
Ctrl+R	Reset puzzle
Escape	Return to main menu

Modes

Mode	Grid	Description
Mini	5x5	Gentle introduction
Easy	6x6	Straightforward logic
Medium	8x8	Moderate challenge
Tricky	9x9	Requires careful deduction
Hard	10x10	Advanced logic chains
Expert	12x12	Maximum challenge

Elo Difficulty

Named modes are compatibility presets. Use --difficulty <0..3000> to target a specific Elo difficulty for generated puzzles.

Quick Start

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