X-sudoku.com: Classic and X

X-Sudoku — Sudoku, but with a twist.

In X-Sudoku, two diagonals join the classic rows, columns, and 3×3 boxes. Every digit 1–9 must appear exactly once along each diagonal — a fourth constraint that turns familiar Sudoku into a fresh kind of puzzle.

Or play classic 9×9 if you're warming up. Both modes share the same calm, paper-bright design, five difficulty tiers, and a long progression that rewards practice without rushing you.

▸ TWO MODES
Classic 9×9 Sudoku and X-Sudoku with diagonal constraints. Start with classic, graduate to X.

▸ FIVE DIFFICULTY TIERS
Easy, Medium, Hard, Expert, Epic. Unlock harder tiers by solving easier ones — the curve is real but never punishing. Over 800 puzzles across both variants.

▸ DAILY PUZZLES
A fresh puzzle every day for both modes. Build a streak; earn bonus points for consecutive days.

▸ HALL OF FAME
Twenty earned titles from Student all the way to Immortal, each with its own hand-drawn icon. Track best times per variant and difficulty, total puzzles solved, longest streak, and every point you've collected along the way.

▸ HELPFUL PERKS — earned, not bought
Free hints, pencil marks, mistake forgiveness, an extra chance, and 24-hour double-points windows. You unlock perks by earning titles, unlocking new difficulties, or hitting a 7-day streak — never via real money.

▸ PURE FOCUS
No accounts. No friends list. No notifications you didn't opt into. The puzzles are yours, played offline, saved locally. One optional purchase removes ads forever — that's the whole monetization model.

▸ CRAFTED DESIGN
Warm serif typography. Soft, paper-like surfaces. Subtle sweep animations when you complete a row, column, or 3×3 box. Light and dark modes that respect your system setting.

X-Sudoku is for the kind of puzzle lover who wants depth without grind. Five minutes between things, or an hour in the evening — pick up a puzzle, place a digit, breathe.