Daily Diagonal Sudoku: Sudoku X Rules and Practice Tips
Daily diagonal Sudoku adds two main diagonals to classic Sudoku. Learn the Sudoku X rules and how to scan diagonals without missing easy moves.
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Get the iPhone App →Daily diagonal Sudoku, also called Sudoku X, adds one extra rule to classic Sudoku: both long diagonals must also contain the digits 1 through 9 exactly once.
That extra diagonal constraint changes how you scan the puzzle. Rows, columns, and boxes still matter, but the two corner-to-corner diagonals can create placements that normal Sudoku would not reveal.
Daily diagonal Sudoku rules
- Every row contains 1-9 once.
- Every column contains 1-9 once.
- Every 3×3 box contains 1-9 once.
- Each main diagonal also contains 1-9 once.
How to solve Sudoku X
- Mark both diagonals before you start.
- Scan diagonal cells after every normal placement.
- Use diagonal missing digits the same way you use row missing digits.
- Do not forget that a diagonal cell still belongs to a row, column, and box.
Why daily diagonal Sudoku feels different
The extra rule gives you more information, but only if you remember to use it. Many missed moves happen because players solve as if the diagonal does not exist.
FAQ
Is diagonal Sudoku the same as Sudoku X?
Yes. Sudoku X is a common name for Sudoku with both main diagonals constrained.
Is daily diagonal Sudoku harder?
It can be easier or harder depending on the puzzle, but it asks you to scan one more type of unit.