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This page keeps the game board near the top so search visitors can start solving instead of reading a long introduction.
hard sudoku
Hard Sudoku
Hard Sudoku is for slower, focused solving. Take your time, use pencil notes, and check mistakes when you want a nudge without turning the puzzle into a guess.
Try another Sudoku mode
Switch to Daily Sudoku, Easy, Medium, or Hard puzzles at any time.
Questions players ask
Sudoku FAQ
What is Hard Sudoku?
Hard Sudoku is a free online Sudoku page with a playable 9x9 board, notes, hints, and mistake checking.
Do I need an account?
No. You can play in your browser and your current progress is saved locally on this device.
Can I use it on my phone?
Yes. The board and number pad are designed to work on small mobile screens.