easy
Diagonals plus the basics. No guessing required.
0 of 25 free easy X Sudoku puzzles used
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X Sudoku
Choose a difficulty
Standard Sudoku rules plus a twist: each main diagonal must also contain 1-9.
Today's editions
Pick a difficulty
medium
Diagonal pencil work and tighter constraints. Still no guessing.
0 of 25 free medium X Sudoku puzzles used
hard
Sparse clues — branching guesses may be required.
0 of 25 free hard X Sudoku puzzles used
From the rulebook
How to play X-Sudoku
X-Sudoku (also called diagonal Sudoku) takes the classic rules, digits 1–9 once per row, column and 3×3 box, and adds one more constraint: both main diagonals of the grid must also contain each digit exactly once.
The diagonals are both the challenge and the gift. The centre cell belongs to both diagonals plus its row, column and box, making it the most constrained cell on the board, check it early. When a digit is placed anywhere on a diagonal, eliminate it along the whole diagonal just as you would a row. Solvers comfortable with regular Sudoku usually find the extra constraint makes X-Sudoku faster to crack at the same stated difficulty, until the hard set, where it bites back.