Sudoku World.

How to play sudoku

Sudoku is a logic puzzle on a 9 × 9 grid divided into nine 3 × 3 boxes. The goal is to fill in the numbers 1 to 9 so that each number appears exactly once in every row, column and box. Some numbers are given at the start, and the rest can be worked out from them. Notes help along the way – small numbers you write into a cell as candidates.

Sudoku types in N2by Sudoku World

• Classic sudoku – six difficulty levels from Novice to Expert.
• Jigsaw sudoku – instead of 3 × 3 boxes, the grid has coloured regions of different shapes.
• Locked sudoku – some cells are held by chains and padlocks that you release with correct numbers in their row and column.
• Lock & key sudoku – find hidden keys, open locks and defeat demons and echoes.
• Daily challenge – a new sudoku every day for all players, with a shared leaderboard and points for placing.

Play for free in your browser on a computer or phone, with no sign-up and no ads. Your game in progress is saved and results go to a shared leaderboard.