Puzzle · Logic Puzzle
Hitori
Play Hitori online. Shade repeated numbers so unshaded rows and columns contain no duplicates. Keep the white area connected. Free in your browser.
The game's own interface may still be in English.
Overview
Hitori begins with a fully numbered grid and asks which numbers should disappear. Shade selected squares so that no number repeats among the remaining white squares in any row or column. Black squares cannot touch along an edge, and all white squares must stay connected. Diagonal black contacts are allowed. The puzzle is not asking you to replace digits or sort the grid: the only essential choice is whether a cell remains white or becomes black. SonoTap hosts the Singles implementation with new generated puzzles and size presets. The connectivity restriction gives otherwise local duplicate-removal choices their depth. Removing the most obvious repeated number can still fail if it blocks the only passage joining two parts of the white area.
How to Play
Click a numbered square to shade it black. Secondary input places a white mark to record a number you intend to keep. Use the Secondary toggle for white marks on a phone. Scan each row and column for duplicate values among unshaded cells, then resolve those duplicates without making adjacent black cells or splitting the white region. A shaded number remains visible enough to inspect your reasoning. Undo reverses the latest mark, while Restart restores the original unmarked grid for another attempt.
Tips & Strategy
When equal numbers flank a cell in a straight line, investigate the middle cell carefully: shading it may prevent either outside duplicate from being removed without creating adjacent black squares. More generally, every black choice forces its four neighbours white. A confirmed white number forces other instances of that number in its row and column black. Follow this alternating chain and check connectivity after each forced group. Near a corner, a black pair meeting diagonally can trap a white square, so edge geometry deserves special attention. Do not assume that resolving every visible duplicate automatically leaves the white area connected.
About this version
Hitori uses the locally compiled singles engine from Simon Tatham’s Portable Puzzle Collection. The original authors retain credit under the MIT license. SonoTap provides the browser adaptation and this guide.
Controls
- Mouse
- Click a numbered square to shade it black. Secondary input places a white mark to record a number you intend to keep. Use the Secondary toggle for white marks on a phone. Scan each row and column for duplicate values among unshaded cells, then resolve those duplicates without making adjacent black cells or splitting the white region. A shaded number remains visible enough to inspect your reasoning. Undo reverses the latest mark, while Restart restores the original unmarked grid for another attempt.
- Touch
- Tap or drag on the board using the same rules as mouse input. Enable Secondary for the alternate mark; numeric games also provide on-screen keys.
Features
- Shade repeated numbers so unshaded rows and columns contain no duplicates. Keep the white area connected.
- Local open-source game engine with original author credits
- Generated puzzles and the upstream Type settings
- Undo and restart controls
- Touch input and a secondary-action toggle
Frequently asked questions
What is the goal in Hitori?
Shade repeated numbers so unshaded rows and columns contain no duplicates. Keep the white area connected.
What is a useful first deduction in Hitori?
When equal numbers flank a cell in a straight line, investigate the middle cell carefully: shading it may prevent either outside duplicate from being removed without creating adjacent black squares. More generally, every black choice forces its four neighbours white.