Very Hard Sudoku

Only 22 givens sit on the 9x9 grid, leaving most of the 81 cells blank from the first second. In the puzzle selection for Very Hard Sudoku, the toughest boards appear in sequence or by direct choice. Fixed digits stay in place for the entire round. No error check appears after a wrong number, and no hint system steps in to rescue a stalled board. That setup fits players who already know regular 9x9 sudoku and want the hardest version on the site.

How to play?

Fill the empty cells with digits 1 through 9, making each number appear once in every row and once in every column. Each 3x3 box follows the same rule. Use notes for possible values when several spaces still fit the same digit. The panel also includes erase and undo. A timer runs during the puzzle, and a pause is available at any point. Pick New Game to load another very hard board from the menu. Use Start Again to reload the current layout and solve the same puzzle from scratch. Advanced Sudoku methods help on these sparse grids because the fixed numbers provide the reference for later placements. Check a newly placed digit against its row, column, and box before moving on.