About the Kakuro
Kakuro is like a crossword built from sums instead of words. The grid is split into horizontal and vertical runs of white cells, and every run carries a clue — the total its digits must add up to. You fill each run with the numbers 1 to 9 so it hits that sum exactly, and no digit may repeat within a single run. That one rule, combined across intersecting runs, is enough to pin down every cell by pure logic. It has been called a mathematical cousin of Sudoku, and once the deductions click it is every bit as moreish. Fresh puzzles are generated each time across two sizes.
How to play
- Pick a puzzle. Each clue is the sum of the run beside or below it.
- Tap a white cell, then tap a number 1–9 (or type it) to place it.
- A run must total its clue with no digit repeated inside it.
- Fill every cell so all runs balance — that wins the puzzle.
What it measures
This test focuses on your logical reasoning, arithmetic fluency and working memory. A Mini Kakuro falls in a few minutes once you spot the tight runs; a Classic grid rewards patient, systematic deduction. A clean, no-mistake solve is the real benchmark.
Why play it
- Combines logic with light mental arithmetic — a dual workout
- The no-repeat-in-a-run rule trains the same elimination logic as Sudoku
- Cross-referencing intersecting sums is a genuine working-memory exercise
Did you know?
- Kakuro began as "Cross Sums" in American puzzle magazines before Japan's Nikoli renamed and popularised it in 1980.
- The name is a Japanese contraction of "kasan kurosu" — literally "addition cross".
- Certain sums force their digits: a run of two cells totalling 3 can only be 1 and 2, which is where solvers start.
- Before Sudoku's global boom, Kakuro was the best-selling logic puzzle in Japan.