Kakuro
Crosswords with numbers: crossing sums.
Each run of white cells must add up to the given sum, using the digits 1 to 9, all different. The grids get bigger with the level.
- Players
- 1 player
- Length
- 5 to 40 min
- Solo
15 days of full access, no account · No download
How to play
Goal
Place a digit from 1 to 9 in every white cell. Each horizontal or vertical run of white cells is announced by a clue cell: the number above the diagonal gives the sum of the horizontal run that starts to its right; the number below gives the sum of the vertical run that starts underneath.
- The digits in a run are all different.
- A digit may repeat elsewhere in the row if it belongs to another run.
Controls
- Tap a cell, then a digit; Notes (N key) for candidates, Auto notes to calculate them.
- The Combinations banner shows live the possible sets of digits for the two runs of the selected cell.
- Backspace or 0: erase. Arrow keys: move. Ctrl + Z: undo.
Techniques
- Unique combinations: 3 in two cells is always 1 + 2; 17 in two cells is 8 + 9; 6 in three cells is 1 + 2 + 3.
- Intersection: a cell belongs to two runs; only the digits common to their combinations are possible.
- Required digit: a digit that appears in every combination of a run and has only one possible place.
- At the higher levels, some hypotheses lead to a contradiction.
About the AI
The generator draws a symmetric template, fills it with digits, then adjusts digits and black cells until an exhaustive search confirms that the solution is unique. A logical solver based on combination tables then grades the grid by the most advanced technique it requires. That same solver provides the explained hints and the Solve button.
Difficulty levels
- Easy5 × 5 grid: unique combinations and single candidates.
- Medium7 × 7 grid: you have to cross the combinations of the rows and columns.
- Hard8 × 8 grid: required digits and naked pairs.
- Expert9 × 9 grid: requires short contradictions.
- Diabolical11 × 11 grid: requires deep contradictions.
