Catdoku is a cat-themed logic puzzle where you find a legal home for every cat on a colored grid. Each completed board has one cat in every row, column, and colored region, while no two cats may touch, even diagonally.
How to Play Catdoku
Study the whole grid before placing a cat. Mark cells that cannot work with an X, then use the remaining possibilities to narrow down each row, column, and colored region. On a 6x6 board, for example, the finished puzzle contains six cats, with one in every row, column, and color, while the other cells remain empty.
A confirmed cat removes its entire row and column from consideration. Its neighboring cells also become unavailable because of the no-touch rule. Check the four diagonal spaces as well as the cells directly above, below, and beside the cat. One certain placement can reduce another region to a single valid cell and start a chain of deductions.
Rules and Failure Conditions
A cat placement must satisfy all four rules:
- No two cats share a row.
- No two cats share a column.
- Each colored region contains only one cat.
- Cats cannot touch horizontally, vertically, or diagonally.
Random guesses are risky because an incorrect placement can cost a fish. Use X marks and elimination instead of filling cells just because they look possible. If a mark is no longer useful, click again to change or remove it.
Tips for Catdoku
- Start with constrained regions: Check colored areas with only a few available cells before open regions.
- Mark around confirmed cats: Eliminate every neighboring cell as soon as a cat is certain, including the four diagonal spaces.
- Cross-check every rule: A cell that fits its color may still fail because its row or column already has a cat.
- Rescan after each placement: Recheck the affected row, column, nearby cells, and colored regions to find the next forced move.
Early puzzles introduce how the rules interact. Later boards use more complex layouts and require closer attention to overlapping restrictions. Hints are available, and daily puzzles provide additional deduction challenges for players who want a fresh board.