A run is a line of white cells between black or clue cells, across or down. Digits can't repeat inside a run, and that one rule makes Kakuro far more logical than it first looks.
Kakuro rules in 30 seconds
- 1Write digits 1–9 in the white cells only.
- 2Each across run adds up to the clue on its left.
- 3Each down run adds up to the clue above it.
- 4No digit repeats within a run.
See it on a board
Watch: how to play Kakuro
Still not sure? Some puzzles click faster when you see them solved. This 10-minute video from puzzlingdotcom shows Kakuro in action.
Reading the board
A Kakuro grid has three kinds of cell. Black cells are unused. Clue cells are split by a diagonal line: the number above the line is the total for the run going across, and the number below it is the total for the run going down. White cells are where your digits go.
The magic combinations
Some totals can only be made one way, and spotting them is the heart of Kakuro:
- Two cells: 3 = 1+2, 4 = 1+3, 16 = 7+9, 17 = 8+9.
- Three cells: 6 = 1+2+3, 7 = 1+2+4, 23 = 6+8+9, 24 = 7+8+9.
- Four cells: 10 = 1+2+3+4, 11 = 1+2+3+5, 29 = 5+7+8+9, 30 = 6+7+8+9.
- Nine cells always total 45, using every digit once.
How to start a Kakuro
- Circle every run whose total has only one combination. Those digits are fixed, just not their order.
- Where two locked runs cross, the shared cell must be a digit both combinations contain.
- For a long run, work out which digits are missing instead: a 9-cell 44 is every digit except 1.
- Keep a note of candidates in each cell, and update the crossing run whenever one is placed.
Worked example
- 1An across run of two cells totals 4, so its cells are 1 and 3 in some order.
- 2Its first cell also starts a down run of two cells that totals 3, which can only be 1 and 2.
- 3The only digit both runs allow is 1, so that cell is 1, and the other cell of the across run is 3.
Kakuro tips and strategies
Hunt unique combinations
Start with the magic totals above. They pin digits immediately.
Cross the runs
Every white cell sits in an across run and a down run. Its digit must be possible in both.
Use the no-repeat rule
16 in two cells can't be 8+8, so it's 7+9. The rule cuts combinations fast.
Short runs first
Two- and three-cell runs have far fewer combinations than long ones.
Common mistakes to avoid
- Repeating a digit in a run because the sum still works.
- Reading the across and down numbers in a clue cell the wrong way round.
- Forgetting a cell belongs to two runs at once.
Play Kakuro in 10+ Number Puzzles
- Tap a white cell to select it; clue and black cells can't be edited.
- Use Notes to track candidates before committing a digit.
- You have 3 lives. A wrong digit costs one.
- Five difficulty levels, each a ladder of stages from Easy to Genius.
- Go online for free: ranked 1v1 duels, rooms where you race, co-op or play in teams, and tournaments.
- 27 more puzzle types in the same app, and online play never costs coins.
Kakuro FAQ
What is Kakuro also called?
Cross Sums. It's often described as a crossword puzzle with numbers.
Can you use 0 in Kakuro?
No. Only digits 1 to 9 are used.
Can a digit repeat in a Kakuro row?
It can appear again in a different run on the same line, but never twice within one run.
