Diagonal rules
A plain-English rule page for the extra two diagonals.
RulesDiagonal
Diagonal Sudoku
Diagonal Sudoku, sometimes called Sudoku X, keeps the classic row, column, and box rules and adds the two long diagonals. This version is now playable in the main board.
Diagonal variant profile
- Rule change
- Both main diagonals must also contain each number once.
- Senior fit
- The extra rule can be shown with two clear diagonal highlights.
- Playable state
- Live now in the main board with a dedicated mode button.
- Design need
- Diagonal highlights must be visible without making the grid noisy.
Why it is a good next variant
Diagonal Sudoku adds a clear visual rule without requiring tiny symbols or cage math.
For senior-friendly design, the diagonals need obvious but low-glare highlighting, which is now built into the live game.
Where to go next
Players who already know classic Sudoku can start playing right away. Newer players may prefer the rules page first, while caregivers and family members may want the senior and printable guides.
The Sudoku X page covers the common alternate name for the same diagonal rule, so searchers who use either phrase land on the right experience.
Diagonal Sudoku Paths
Diagonal for seniors
Why the visual rule works well for older adults when contrast stays clear.
Senior GuidePrintable diagonal
Open a diagonal-ready print sheet with matching answers.
PrintableSudoku X
The common alternate name for Diagonal Sudoku.
Sudoku XPractical Questions
Is Diagonal Sudoku playable here now?
Yes. Use the Diagonal 9x9 mode on the main board to play Sudoku X with the diagonal rule enabled.