Play Modes

Classic

Classic 9×9 sudoku, ready anytime.

Killer

Planned: cages and sum constraints.

Daily Challenge

A new puzzle every day. Share your streaks.

Tournaments

Multiplayer races with global rankings.

Sudoku Challenge

Play instantly in the browser with keyboard, mouse, or touch.

Time 00:00

Mistakes 0 / 3

Filled 0/81

Hints 0

Difficulty Language

Auto-saved.

Mobile tip: tap a cell, then enter a number.

Rules at a Glance

Each row, column, and 3×3 box must contain 1–9 with no repeats.
Select a cell, enter a number, or toggle Notes to pencil in candidates.
Exceed the mistake limit to lose; restart or undo to recover.

Solving Tips

Start with the fewest candidates and scan rows/columns for singles.

Shortcuts

Number keys 1–9: enter a value
Backspace/Delete: erase
N: toggle Notes
H: hint
U: undo

Roadmap

Full Killer mode with a cage editor
Accounts and cross-device sync
Rankings and tournaments
More variants (X, Windoku, Samurai)

Configurable Items

difficultyLevels: tune hole counts from Easy to Extreme.
maxMistakes: set the failure threshold.
CSS variables: --accent for the theme color, --bg for the background.