Play Number shading puzzle (Singles) online Works — plays right here, unlimited puzzles
Guide updated October 2026 · Runs via WebAssembly (native port)
Singles is a shading puzzle. The grid starts full of numbers, with repeats in many rows and columns. You blacken squares until no number appears twice in any row or column, without letting two black squares touch side by side and without cutting the white squares into separate parts. The puzzle is ready below; the default is a 5x5 grid.
Controls — what does what
| Action | Keyboard | Mouse / touch |
|---|---|---|
| Shade a square black (again to restore) | Enter | Left-click |
| Circle a square as definitely white | Space | Right-click |
| Show or hide numbers under black squares | - | Click outside the grid |
| Move the cursor | Arrow keys | - |
| Undo / redo | U or Ctrl+Z / R or Ctrl+R | Game menu |
FREE This is the complete game, free. Open source under the MIT licence: the complete puzzle, with a new grid every time.
Singles is from Simon Tatham's Portable Puzzle Collection, © Simon Tatham and contributors, used under the MIT licence. Built from source by scripts/build-puzzles.mjs.
How to play
- Shade some squares black so that no number appears more than once in any row or column.
- No two black squares may be next to each other horizontally or vertically.
- All the white squares must stay connected as one region, joined by edges rather than corners.
Sizes and difficulty
The Type menu offers 5x5, 6x6, 8x8, 10x10 and 12x12 grids, each at Easy or Tricky. Custom sets any size and difficulty.
Solving tips
When a number sits between two copies of itself in a row (like 3 4 3), the middle one is safe and both ends are under suspicion; in a triple like 2 2 2, the middle is white and the outer two are black. Every square next to a black square must be white, so circle those immediately. If shading a square would wall off part of the white area, it must stay white. A number with no repeat in its row and column can be circled at once.
Where this puzzle comes from
Singles is part of Simon Tatham's Portable Puzzle Collection, a set of about forty logic puzzles written by Simon Tatham and contributors and released under the MIT licence. Every grid is generated on the spot, so the supply never runs out, and for the grid-logic puzzles the generator makes sure each has exactly one solution, reachable by reasoning rather than guessing. The version here is the collection's own code compiled to WebAssembly; the Game menu can save a puzzle to a file and load it again, and the Type menu changes the size and difficulty.
Frequently asked questions
What is this puzzle called elsewhere?
Nikoli publishes it as Hitori. Singles is the name in Simon Tatham's collection, where it was contributed by James Harvey.
What does the circle do?
It marks a square you have decided must stay white. The game does not check circles; they are notes that stop you shading that square by mistake.
Is Singles free to play here?
Yes, with no limit on the number of puzzles. Singles is open-source software under the MIT licence, and every grid is generated fresh when you press New game.
Does it work on a phone or tablet?
Yes. A tap works as a click and the puzzle resizes to fit the screen. Puzzles whose controls use the right mouse button are easier with a mouse.
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Number shading puzzle (Singles) isn't ours to give away — we host it, we didn't write it. But eleven of the games here we did write from scratch, and those are free for anyone to put on their own page: one line of HTML, no account, no permission, no attribution beyond a credit line.