🧮 How to play Kakuro (rules and strategy)
By Miguel Arechaga
Kakuro is known as the "Sudoku of sums": instead of visual clues, each run on the board gives you a number you need to reach by combining digits from 1 to 9 without repeating any. It looks like arithmetic, but it's actually pure logical reasoning, just like classic Sudoku.
What is Kakuro?
Kakuro is a number puzzle played on a grid with black cells (holding clues) and white cells (to fill in). Each black cell can carry a number in its top-right corner, showing the sum of the column starting below it, and another in its bottom-left corner, showing the sum of the row starting to its right.
How to play Kakuro step by step
- Look at a run (a group of consecutive white cells, horizontal or vertical) and its associated clue number.
- Fill those cells with numbers from 1 to 9 so they add up to exactly the clue's number.
- Within a single run, no number can repeat.
- Every white cell belongs to both a horizontal run and a vertical run at once, so its value must satisfy both sums simultaneously.
- The puzzle is complete once every white cell is filled and every sum checks out.
Strategy: start with the unique combinations
Some sums can only be formed one way with a given number of cells. For example, a 2-cell run that sums to 3 can only be 1+2, and a 2-cell run that sums to 17 can only be 8+9. Spot these "forced" runs first: they give you sure numbers right from the start, with no need to guess anything.
Then use those placed numbers to deduce the rest: if a cell belongs to a horizontal run that's nearly solved and a vertical run with fewer options, cross-reference both to rule out candidates, exactly like you would in a Sudoku.
Quick tricks to solve Kakuros
- Memorize the most common combinations: low sums with few cells (or high sums with nearly-full cells) usually have only one possible solution.
- Work the shortest runs first (2 or 3 cells): they have fewer combinations and get solved sooner.
- Mentally track which numbers "don't fit" in a run rather than which ones do; sometimes it's faster to rule things out.
- If you get stuck, look for the cell where the horizontal and vertical runs with the fewest possible candidates intersect.
Kakuro blends Sudoku's elimination logic with a small arithmetic component, making it a perfect way to mix things up without losing that feeling of a puzzle solved through pure deduction.
