Hard Sudoku online
A demanding Sudoku level with fewer openings and more deductions across rows, columns and boxes.
Play Hard SudokuWho is Hard Sudoku for?
This level is best suited to experienced players ready to combine several solving techniques. The puzzle runs directly in your browser, so there is nothing to download.
Helpful features
- Candidate notes for uncertain squares
- Hints with a short logic explanation
- Undo, erase, pause and resume controls
- Optional account progress, points and friend challenges
A useful solving approach
Begin by scanning for missing digits in the most complete rows, columns and boxes. Recheck the grid after every confirmed number because one placement often creates the next opportunity.