Kakuro
Cross-sum logic puzzles
Cross-sum logic · fill white cells so each run hits its target
Goal
Fill the white cells so each across and down run adds up to its clue, using 1–9 with no repeats inside a run.
Rules
- A clue above the diagonal sums the run going down; below-left sums the run going right.
- Use digits 1–9 only; no digit repeats within a single run.
- Black cells separate the runs.
- No zeros are ever used.
How to play
- Start with short runs that have a unique combination (a 2-cell run summing to 3 is 1 and 2).
- Use the crossing of an across-run and a down-run to pin a digit.
- Track which digits are still available in each run.
Tip
A run’s minimum and maximum sums lock its combinations — clues near those extremes are the fastest to crack.