Sudoku

How sudoku works

It’s not arithmetic

There’s nothing to add up. The nine numbers are just symbols — they could be nine animals.

The rule

Every row, every column and every block of nine squares holds the numbers 1 to 9, each one exactly once.

row
column
block

Putting a number in

Tap an empty square. Then tap one of the numbers.

An empty square in a block, marked as chosen, and the number 6 marked on a row of keys from 1 to 9.

Tap that number again to take it out.

Your first square

Look for a row, column or block that’s nearly full. Often only one number can go in a square.

A block of nine squares with eight numbers in it: 3 4 5, 1 8 9, and 7 2. One square is empty.

This block has eight numbers. Only the 6 is missing.

A block of nine squares, now complete: 3 4 5, 1 8 9, 6 7 2.

So that square is a 6.

A row of nine squares reading 3, empty, 5, 7, 2, 1, 9, 6, 8.

The same works along a row, missing a 4.

If a number turns up twice

The same number can’t be in one row, column or block twice. If it happens, both are marked until you change one.

A row reading 3, 4, 5, 7, 2, 1, 9, 6, 9. Both 9s are marked.

If you get stuck

You never need to guess. Try another row, column or block — or press Hint.

A block of nine squares, all of them lit, with one square still empty.

Hint helps as much as you ask. Press once to see where to look, again for the reason, and a third time to fill the square in.

Nothing is timed. Your progress saves by itself, so you can stop and come back.

Start an Easy puzzle

Not a member? Play this week’s free sudoku, or see the Puzzle Club.