⬛ Hitori
🧩 Logic · 0 playsHitori
Shade away the repeated numbers without breaking the grid into pieces.
About Hitori
The grid arrives with numbers repeating along its rows and columns, and you shade cells until no number appears twice unshaded in any line. Two further rules keep the puzzle honest: shaded cells may never share an edge, and every unshaded cell must remain joined to the rest in one connected region. Those rules do much of the work between them — a cell with shaded neighbours on two sides has to stay clear, and a pair of identical numbers standing side by side settles a good deal about what surrounds them. Hitori rewards solvers who mark what must stay as diligently as what must go.
How to Play
Tap a cell to shade it, and tap again to clear it. No number may appear more than once unshaded in any row or column. Shaded cells must not touch edge to edge, and all unshaded cells must stay connected to one another.
💡 Tips & Strategy
Three techniques solve most of the board, and the first is the strongest. Wherever three identical numbers sit consecutively in a line, the middle one must stay unshaded — shading it is unnecessary and shading both outer ones would leave a duplicate, so the middle survives and both neighbours go dark.
The second is the sandwich. Where a pattern reads a, x, a in a line, the x between them must stay unshaded. One of the two matching outer numbers has to be shaded, and since shaded cells may never touch orthogonally, the cell between them cannot also be shaded.
The third is chaining, and it does the bulk of the work. Shading any cell immediately confirms all four of its neighbours as unshaded; confirming a cell as unshaded immediately forces every duplicate of its value in that row and column to be shaded. Alternate between the two and deductions cascade across the grid.
Keep connectivity in view throughout. All unshaded cells must form one connected group, so a shading that would cut a region off — or strand a corner — is wrong however well it satisfies the duplicate rule. Late in a puzzle, connectivity is often the constraint that decides the last few cells.