How to Solve Kakuro: Rules, Tips and Strategies for Beginners
Kakuro looks like a crossword, but instead of words you fill the white squares with digits — and instead of clues you get sums. Every run of white cells must add up to the number in the black cell at its start, with no digit repeated inside a run. It plays like a cross between a crossword and sudoku, and once you learn a few patterns, it solves almost by itself. Here's how it works and how to get good at it fast.
The rules in one minute
Fill every white cell with a digit from 1 to 9. Each horizontal run of white cells must add up to the clue in the black cell at its left, and each vertical run must add up to the clue in the black cell above it. No digit may repeat within a single run — though the same digit can appear in different runs that cross. A kakuro puzzle has exactly one solution, reachable by logic and simple arithmetic.
How to read a clue
Black cells hold two small numbers. The number in the top-right corner is the sum for the run of white cells to its right; the number in the bottom-left corner is the sum for the run of white cells below it. A black cell with only one number sits at the edge, where only one run exists. On our kakuro generator the clues are laid out exactly this way, so you can practice on a printed puzzle.
1. Start with the smallest runs
Two- and three-cell runs are the easiest to crack, so sweep the grid for them first. A two-cell run of 3 can only be 1 + 2, and a run of 17 can only be 8 + 9. The longer a run, the more combinations it has — leave those for later, when crossing digits have narrowed them down.
2. Learn the unique combinations
A handful of sums have only one possible combination, and recognizing them fills cells instantly. For two cells: 3 is 1+2, 4 is 1+3, 16 is 7+9 and 17 is 8+9. For three cells: 6 is 1+2+3, 7 is 1+2+4, 23 is 6+8+9 and 24 is 7+8+9. When you see one of these, you know exactly which digits the run contains — then use the crossing run to decide which goes where.
3. Use crossing runs like sudoku
Every white cell belongs to two runs — one horizontal and one vertical. List the possible digits for the across run and the down run; any digit that appears in both lists is the cell's answer. This is the heart of kakuro, and it's the same elimination logic that makes sudoku satisfying. If a two-cell across run of 4 (1+3) crosses a two-cell down run of 3 (1+2), the shared cell must be 1 — the only digit common to both.
4. Work from the outside in
The runs that touch the grid's edge are often shorter and have fewer combinations, because long runs need room. Clear the outer ring first — those answers then restrict the runs they cross, which cascades toward the centre of the grid.
5. Jot down candidate digits
In the corner of each white cell, pencil in the digits the run still allows. When a digit gets ruled out by the crossing run, cross it off. Solver's notation like this turns a confusing grid into a tidy elimination chart — and on screen, our kakuro maker lets you type digits directly and check your work as you go.
6. Remember that 1 through 9 adds up to 45
This fact rescues you when a long run fills most of its cells. If a nine-cell run of 45 is nearly complete, the missing digit is simply 45 minus the sum you already have. The same trick works on shorter runs: once you know which digits a run contains, the leftover is arithmetic.
7. Avoid the classic mistake
The most common error is repeating a digit inside a run — 1 + 1 + 6 looks like it makes 8, but a run can never hold two of the same number. Double-check every run you complete: the sum must match, and every digit inside must be different. If you're stuck, revealing the answer key is a great way to see the pattern you missed.
Practice with a printable kakuro
Kakuro improves with practice, and the fastest way to practice is a fresh puzzle. Generate one in seconds on the kakuro generator — pick a grid size and difficulty, then print the blank puzzle or solve on screen with instant checking. Start with a small easy grid and work up to the harder ones, where runs get longer and the combinations get trickier. If you enjoy number logic, sudoku is a perfect companion puzzle.