How to play Kakuro
Kakuro rules: fill each white cell with a digit 1–9. The digits in every across and down run must add up to the clue at its start, and no digit repeats within a run.
Step by step
- Read the clues. Each black cell may show one or two numbers. The top-right number is the total for the white cells to its right; the bottom-left number is the total for the white cells below it.
- Fill with 1 to 9. Put a single digit from 1 to 9 in each white cell. Zero is never used.
- Make each run add up. A run is an unbroken line of white cells across or down. Its digits must add up to its clue.
- No repeats in a run. A digit can appear only once in any run. That's why 4 in two cells must be 1 + 3, never 2 + 2.
- Start with forced combinations. Some clues allow only one set of digits, like 3 in two cells (1 + 2) or 17 in two cells (8 + 9). Begin where those runs cross.
- Cross-check across and down. Every white cell belongs to one across run and one down run. The digit must fit both, which narrows the options quickly.
A tiny worked example
Suppose an across clue says 4 over two cells and a down clue says 3 over two cells, and the two runs share their first cell. The 4-run must be 1 + 3 and the 3-run must be 1 + 2. The only digit in both sets is 1, so the shared cell is 1. That makes the rest of the 4-run 3 and the rest of the 3-run 2.
Playing on Puzzdoku
- Tap a white cell, then a digit on the pad, or type 1–9. Arrow keys move between cells; Tab moves through the page controls. Turn on Notes (or press N) to pencil in candidates.
- The combination helper lists the digit sets for the selected cell's runs.
- Clues turn green when their run is complete and correct, red when the sum is too high or wrong.
- Duplicates in a run are outlined in red. Show mistakes checks digits against the solution.
Play Kakuro now Next: combinations to memorise
Frequently asked questions
What are the rules of Kakuro?
Fill every white cell with a digit from 1 to 9. The digits in each across or down run must add up to the clue at the start of that run, and no digit may repeat within a run.
Where do I start a Kakuro puzzle?
Look for clues with only one combination, such as 3 or 4 in two cells, 16 or 17 in two cells, 6 or 7 in three cells, and 23 or 24 in three cells. Then check where those runs cross other runs.
Is Kakuro a math game?
It uses addition, but only of small numbers. Most of the solving is logic: working out which digit combinations are possible and where they overlap.
What does the combination helper show?
When you select a white cell, the helper lists every set of digits that can fill that cell's across and down runs. Sets that conflict with digits you've already placed are crossed out.