Free Online Kakuro
Fill white cells with digits 1–9 so that each horizontal or vertical run of cells adds up to its clue, and no digit repeats within a run. Also called Cross Sums — a number crossword that rewards logical deduction. No download needed.
How to Play Kakuro
- The grid looks like a crossword with black and white cells. Black cells carry clue numbers.
- A clue in the lower-left triangle of a black cell applies to the white cells directly below it (down run).
- A clue in the upper-right triangle applies to the white cells directly to its right (across run).
- Fill each white cell with a digit 1–9 so that the digits in each run sum to that run’s clue.
- No digit may repeat within a single run (similar to Sudoku’s uniqueness rule).
- The puzzle is solved when all white cells are filled correctly.
Kakuro Tips & Strategy
- Learn common combinations: a 2-cell run totalling 3 must be 1+2; totalling 17 must be 8+9. These fixed combos are powerful starting points.
- Focus on runs with only one valid digit combination — they reveal digits immediately.
- Cross-reference intersecting across and down runs to narrow candidates in shared cells.
- Subtract known digits from a run’s clue to deduce what remaining cells must sum to.
- Use the Notes mode to record candidate digits in each cell as you work through the logic.
Frequently Asked Questions
- What is another name for Kakuro?
- Kakuro is also called Cross Sums — a numeric crossword puzzle originating in Japan.
- Can digits repeat in a run?
- No — each digit 1–9 may appear at most once within any horizontal or vertical run.
- Is every puzzle uniquely solvable?
- Yes, puzzles are generated to have exactly one valid solution.