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Play Sudoku online — easy, medium, hard; unlimited puzzles
How to play
Tap a cell, then enter a digit from the keypad or keyboard. The selected cell's row, column and box are highlighted and cells with the same digit stand out. A digit fades on the keypad once all nine copies are placed.
Difficulty
Easy starts with about 40 clues and solves with single-candidate and single-position logic. Medium has around 32 clues and calls for notes. Hard, around 27 clues, needs pairs, pointing patterns and the occasional X-wing.
Basic techniques
If only one digit fits a cell, write it (naked single). If a digit can go in only one place within a row, column or box, write it there (hidden single). Two cells sharing the same two candidates eliminate those candidates elsewhere in the unit (naked pair).
Frequently asked questions
What are the rules of Sudoku?
Fill the 9×9 grid with digits 1–9 so that every row, every column and every 3×3 box contains each digit exactly once. Given digits are fixed.
Do the puzzles have a unique solution?
Yes. The generator builds a full grid, then removes digits one by one while counting solutions; any removal that would allow a second solution is reverted.
How do notes work?
Press 'Notes' and type candidates into a cell; when a digit is placed, that candidate is removed from notes in the same row, column and box. The N key toggles notes mode.
What do hint and check do?
Hint fills the selected (or a random) cell with the correct digit — three per game. Check marks wrongly entered cells in red.