How to play
Kakuro: rules, sums and solving techniques
Kakuro works like a number crossword: every run must reach a target sum without repeating a digit. This guide shows you how to read the clues, recognise useful combinations and use crossings before trying a puzzle from the Kakuro library.
What is Kakuro?
Kakuro is a sum puzzle played on a grid of black and white cells. White cells hold digits from 1 to 9. Black cells separate the runs and may contain the sum clues.
Goal of the game
Fill every white cell so that each horizontal and vertical run reaches its clue total, with no repeated digit inside that run.
Rules
Rule 1
Fill white cells with digits from 1 to 9.
Rule 2
Each clue gives the sum required for its run of white cells.
Rule 3
A digit cannot repeat within the same run.
Rule 4
Every white cell belongs to one horizontal run and one vertical run, so the two constraints meet in that cell.
Every DIGIGMA puzzle has a logical solution. You do not need to guess.
How to read a clue cell
A clue cell is dark and divided by a diagonal. The across sum appears at the top right; the down sum appears at the bottom left. If a direction has no run, that half is simply left blank.
The 17 at the top right belongs to the horizontal run (8 + 9). The 4 at the bottom left belongs to the vertical run (1 + 3).
1 + 3 = 4 works. 2 + 2 does not, because a digit cannot repeat within the same run.
In Ranked mode
Ranked mode does not highlight mistakes while you enter digits. Check solution only tells you that at least one error exists; it does not identify the cell.
If you get stuck
Look for runs whose length and target sum allow only one or two combinations, then use the crossing runs to narrow them further. Draft is especially useful for keeping those possibilities visible.
Interactive tutorial
The tutorial below teaches you how to read Kakuro clues and use the keypad on a small teaching grid. Afterwards, open the Kakuro library and try a full puzzle.
FAQ
- Which number is across and which is down?
- The across sum is at the top right of the diagonal; the down sum is at the bottom left.
- Can a run use the same digit twice?
- No. Every digit in a run must be different.
- Do black cells without a clue do anything?
- They simply separate runs. You never enter a digit in those cells.
- Is there more than one solution?
- No. Every DIGIGMA Kakuro is built with a unique solution.