Learn Kakuro
Kakuro, also called Cross Sums or Cross Addition, is a number puzzle that looks like a crossword and thinks like arithmetic. You do not guess. Every cell is decided by a clue sum and a set of digits that may not repeat.
Start with How to solve Kakuro if you have never played. It walks through a whole puzzle one step at a time.
How to solve Kakuro
The rules, the first two steps, and how to keep going without guessing.
Sum Combinations Cheat Sheet
Every sum, every run length, every set of digits. The one page worth bookmarking.
The technique guides
Twelve techniques from the last cell in a run to contradiction forcing.
Notation
How to read r2c3, "Across 16" and a set like {7,9} in this site and in the app.
Glossary
Run, clue, partition, Magic Block, candidate, forced move: the words this site uses.
Difficulty levels
What Trivial, Easy, Medium, Hard and Extreme mean, and which techniques each needs.
The app manual
Pencil marks, the coach, the "Why not?" prover, the Daily Puzzle and the settings.
The three rules
- Each run of white cells adds up to the clue in its corner.
- Digits are 1 to 9.
- A digit never repeats inside a run.
That is all. Everything else is deduction.