Dominosa
Dominoes left: 0
- Category
- Puzzle
- Players
- 1
- Controls
- Tap
- Set
- 0-0 to 3-3
- Loads
- Plays instantly
Controls
| Tap a cell | Select it. |
| Tap a neighbour | Join them into a domino. |
| Tap a placed domino | Break it apart again. |
Next up
| Tap a cell | Select it. |
| Tap a neighbour | Join them into a domino. |
| Tap a placed domino | Break it apart again. |
Dominosa shows you a grid of numbers that is really a complete set of dominoes laid flat with the borders rubbed out. Every domino from double blank up to double three appears exactly once, and your job is to work out where each one lies.
The elegance is that the numbers alone are not enough — the same pair appears in several places, and only one arrangement uses each domino exactly once. That uniqueness constraint is what turns a grid of digits into a genuine deduction puzzle.
Start with the doubles. A pair of identical numbers side by side is often the only place that double can be, and each one you place removes possibilities everywhere else.
Look for pairs that appear only once. If a particular combination shows up in exactly one place on the grid, that domino is settled immediately.
Watch for isolated cells. A cell whose only remaining neighbour is already used must pair with what is left, and those forced placements cascade quickly.
Track which dominoes you have used. The constraint is that each appears exactly once, so a combination you have already placed can be ruled out everywhere else on the board.
Every combination from double blank up to double three, ten in total.
No, and that restriction is the main source of deductions.
Four rows by five columns, which is exactly twenty cells for ten dominoes.
Yes, each grid is made by laying a real set down and then hiding the borders.
No sign-up, no email, no account. Open the page and Dominosa is ready to play straight away, on a phone or a desktop.