Best –
How to play
Goal
Fill every empty square so that each row, each column and each of the nine 3×3 boxes contains the numbers 1 to 9 exactly once.
How it works
- The darker numbers are given and can't be changed.
- Tap an empty square, then tap a number below (or type it) to fill it in. Tap ⌫ or press Backspace to clear it.
- The selected square's row, column and box are shaded, and every copy of the same number is highlighted.
- A number that repeats in a row, column or box turns red, so you can spot clashes.
- A number on the keypad fades once all nine of it are placed.
- Every puzzle has exactly one solution.
- Mini is a 4×4 grid with 2×2 boxes and only the numbers 1 to 4. It is the perfect first Sudoku, especially for children.
Tips
- Scan for a number: pick one number, say 5, and check each box. Often only one square in a box can hold it.
- Look for the last option: find a square where eight of the nine numbers already appear in its row, column and box. Only one number fits.
- Start with the numbers that already appear most often on the grid.
- If you're stuck, go row by row and ask “where can the missing numbers go?”
The history of Sudoku
The puzzle builds on Latin squares studied by Swiss mathematician Leonhard Euler in the 1700s. The modern form appeared in a US magazine in 1979 as “Number Place”. In 1984 the Japanese publisher Nikoli named it Sudoku, short for “each digit must be single”, and it became a worldwide craze in 2005.