⤬ Diagonal Sudoku (X-Sudoku)

Sudoku with a twist: the two diagonals must also hold 1–9. Play free in your browser, or print it to PDF.

✓ Free Forever · ✓ No Signup · ✓ No Upload · ✓ Works Offline

🔒 Played entirely in your browser. Puzzles are generated and solved on your device. Nothing about your game is uploaded, and there is no account or tracking.

Features

  • The diagonal rule — On top of rows, columns and boxes, both main diagonals must contain 1–9 — a tighter, tougher solve.
  • Daily X-Sudoku — A new shared diagonal puzzle each day, so you and friends can race the same board.
  • Notes, hints & check — Pencil in candidates, reveal a square, or check your grid when you get stuck.
  • Printable PDF — Export the diagonal puzzle and its solution as a clean A4 PDF for pen and paper.

How It Works

  1. Mind the diagonals — Both corner-to-corner diagonals must also hold 1–9 with no repeats.
  2. Play — Tap a cell and type — the diagonals are tinted to help you track them.
  3. Print it (optional) — Export a printable PDF with the answer on the second page.

Use Cases

  • A harder daily brain workout
  • A fresh twist on classic Sudoku
  • Print X-Sudoku for a club or classroom
  • Build a PDF pack of diagonal puzzles

Frequently Asked Questions

What is Diagonal (X) Sudoku?

It is Sudoku with one extra rule: each of the two main diagonals must also contain 1–9, on top of the usual rows, columns and 3×3 boxes.

Is X-Sudoku harder than normal Sudoku?

Usually, yes. The diagonal constraint removes options, so it rewards spotting and using that extra rule.

Does each puzzle have a unique solution?

Yes. Every puzzle is generated to have exactly one solution, diagonals included — no guessing between two valid answers.

Can I print diagonal Sudoku?

Yes — export a clean A4 PDF with the puzzle and the solution on a second page.

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