How to Use
- Set run length — how many white cells in the run
- Enter the target sum from the clue cell
- Use Filter numbers to exclude digits already placed in that row or column
- Check Insights for digits that must or cannot appear
- Use the Intersection Helper to find which digits are valid at a cell where two runs cross
The Intersection Helper
When an across run and a down run cross, only digits that appear in both runs' valid combinations can go in that cell. Enter both runs' lengths and sums — the helper highlights the shared digits automatically.
Solving Strategies
- Start with runs that have only one combination — those cells are solved immediately
- Check Insights for must-have digits — they belong in the run regardless of order
- Use intersections to narrow crossing cells to a single candidate
- Exclude digits placed elsewhere in the same row or column using the filter
What is Kakuro?
Kakuro is a logic puzzle sometimes called a "mathematical crossword." Black clue cells give a target sum for each horizontal and vertical run of white cells. Every run must use unique digits 1–9 that add up to the target — no digit may repeat within a single run.