How to Play Dominosa
A complete set of domino pieces is hidden in the grid. Determine which cells form each domino without using any piece twice.
Try it now — Easy 6x6 →The Rules
- A complete set of domino pieces is hidden in the number grid
- Draw borders to identify each domino — every piece in the set appears exactly once
- Dominoes are 1×2 or 2×1 in size — two adjacent cells
- No two cells can form the same number pair (same domino) more than once
Available in 3 sizes (4x4, 6x6, 8x8) and 3 difficulty levels (easy, normal, hard).
See It in Action
Draw borders to identify each domino piece — the complete set is hidden exactly once in the grid
How to Play
- List all domino pieces in the full set and track which have been placed
- Find number pairs that appear only once in the grid — those two cells must form that domino
- After placing a domino, mark it as used and eliminate that number pair from all other adjacent cell pairs
- Use elimination: if a number pair's only remaining valid position is one specific pair of cells, place it there
Pro Tips
Start with the most constrained pairs — number combinations that appear only once or twice in the grid
Cross off placed dominoes from your list immediately to avoid accidentally using a piece twice
For larger grids, a tally sheet of remaining domino pieces dramatically speeds up the logic
Frequently Asked Questions
What is Dominosa?
Dominosa presents a grid of numbers that contains a complete set of dominoes. Your task is to draw borders around the dominoes to show where each piece is placed. Every domino in the set appears exactly once.
Choose Your Challenge
Start with easy to learn the rules, then progress to harder difficulties.