Enter your Sudoku X puzzle below. Remember, in addition to standard rules, both main diagonals must contain the numbers 1-9 without repetition. Click "Solve Puzzle" to see the solution.
Sudoku X is a 9×9 variant in which each main diagonal must also contain the digits 1–9 without repetition. This solver checks rows, columns, 3×3 boxes and both corner-to-corner diagonals while searching for a completion compatible with the clues you enter.
Choose this solver only for a puzzle that explicitly uses the diagonal rule. A standard Sudoku does not require unique digits on its diagonals and may therefore produce a different result or no result here.
A filled board is one completion satisfying the classic and diagonal constraints. You can compare it with your own grid, but the page does not issue a single-cell hint, highlight a specific wrong deduction or explain techniques such as diagonal intersections step by step.
The algorithm stops at the first valid completion. It does not determine whether a second solution exists and therefore cannot certify that a custom Sudoku X is uniquely solvable. Use a dedicated solution counter before publishing a handmade puzzle.
Check the ordinary rows, columns and boxes first, then scan both main diagonals. A clue may be valid under classic Sudoku rules but invalid under Sudoku X, particularly near the centre where diagonal constraints overlap.