Sudoku X
Fill the grid so every row, column and 3×3 box holds the digits 1 to 9 exactly once, and so do the two long diagonals, shown striped. Every puzzle has one solution you can reach by logic alone.
Also try Sudoku → Also try Killer Sudoku →
How to play Sudoku X
How to play
Tap a cell, then tap a number on the pad (or type 1 to 9). Each digit may appear only once in every row, column and outlined box, and once on each of the two diagonals. Turn on Notes (or press N) to pencil in candidates; placing a digit removes matching notes from every cell it sees, along the diagonals too.
The diagonals
The cells of the two long diagonals are striped and joined by a dashed line. The top-left diagonal runs from the top-left corner to the bottom-right one, the top-right diagonal from the top-right corner to the bottom-left one. The centre cell lies on both, so it sees more cells than any other.
Levels and hints
Levels are set by the hardest step a logical solver needs. Gentle needs only singles, including the last place for a digit on a diagonal. Moderate adds pointing and box/line reductions (also where a box meets a diagonal) and pairs. Tough needs triples, X-wings, XY-wings or swordfish. Hint shows the next step, names it and explains it in one sentence.
Questions
What is Sudoku X?
Sudoku X, also called diagonal Sudoku, is a 9×9 Sudoku with one extra rule: the two long diagonals must each hold the digits 1 to 9 once, just like every row, column and box.
How is Sudoku X different from normal Sudoku?
The diagonals give you two more houses to work with, so a Sudoku X needs fewer given digits. Cells on a diagonal see more cells than usual, and the centre cell, on both diagonals, sees the most.
How do the diagonals help?
Look for the last place a digit fits on a diagonal, and for a box where a digit can only sit on the diagonal: then it can’t go anywhere else on that diagonal. Hints point these out by name.
Does every Sudoku X here have exactly one solution?
Yes. Every puzzle was checked by a solution counter that found exactly one solution, and finished by a logical solver at its level, so you never need to guess.
Is there a daily Sudoku X?
Yes. The daily puzzle is a Moderate Sudoku X that is the same for everyone and changes at midnight UTC.