The idea in one minute
What is sudoku?
Sudoku is a placement puzzle. You fill a 9×9 grid so that each row, each column, and each 3×3 box contains the digits 1 through 9 exactly once.
Wednesday, September 9, 2026 · easy
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Where the name comes from
The modern form was popularized in Japan. The idea is older: it is a Latin square with box constraints.
What it is not
You do not add the numbers. Arithmetic is not required. The skill is elimination — seeing which digit is still legal.
Questions
- Is sudoku math?
- It uses digits, but the reasoning is logic, not calculation.
- How many solutions should a puzzle have?
- A well-formed sudoku has one. Our generator aims for that on medium and hard.