Logic puzzle · Shade the duplicatesHitori,
Hitori,
shade the duplicates.
Every row and column should read each number only once. Shade the extras without isolating the rest.
- Time
- 0:00
- Moves
- 0
- Hints
- 0
Tap to cycle · Number → Shaded → Circled
About the gameHow Hitori works,
How Hitori works,
in short.
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Each line should read once.
When the puzzle is solved, every row and column shows each number at most once. Duplicates in the starting grid are the candidates you will shade out.
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Tap a cell to cycle Number → Shaded → Circled.
Shading removes a duplicate; the circle is your personal marker for a number you have decided to keep. Two shaded cells may never share an edge, so the four cells touching a shaded cell stay white.
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Whites must stay connected.
All unshaded cells must form one orthogonally connected region — no isolated pockets. The board is solved when every row and column is duplicate-free, no two shaded cells touch, and the whites remain joined.
Questions
Hitori questions, answered.
Hitori is a Japanese deduction puzzle from Nikoli, the same publisher that brought Sudoku, Slitherlink, and Kakuro into the open. You start with a grid of numbers and shade cells so that every row and column reads each number only once.
Tap a cell to shade it. Tap again to circle it (a way to mark cells you have decided must stay unshaded). A third tap clears it back to its original number. The board flags rule violations in clay as you play.
First — no number repeats among unshaded cells in any row or column. Second — shaded cells never share an edge. Third — every unshaded cell must connect to every other through a chain of orthogonal neighbours. A solution satisfies all three at once.
Circling is an aid, not a rule. When a shaded cell is locked in, every neighbour of it must stay unshaded — circling those cells helps you remember and avoids accidentally shading them later. The circle does not affect the win check.
Yes. The generator counts solutions of every candidate puzzle and only ships ones with exactly one valid shading. You should always be able to reach the answer through deduction — if you get stuck, ask for a hint.
The hint reveals one cell from the canonical solution and locks it. Cells that should be shaded turn solid; cells that should stay white get a moss-coloured circle so you can tell at a glance which decision was made for you.
Sudoku starts with a sparse grid you fill in. Hitori starts with a dense grid you reduce. The unique-once-per-line rule is similar in spirit, but Hitori adds two spatial constraints — no adjacent shading, and white connectivity — that change how the deductions chain.
Yes. The board is sized for thumb taps and the three-state cycle keeps all interaction on a single touch. Hint, clear, and new-game pills stay in the toolbar across all screen sizes.
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