Sudoku
Sudoku is the world's most popular number puzzle. Place digits 1–9 into a 9×9 grid so that every row, every column, and every 3×3 box contains each digit exactly once. The puzzle starts with some cells already filled in — your job is to deduce the rest using pure logic, no guessing required.
How to Play
Click or tap an empty cell to select it, then type or tap a number to fill it in. Toggle the notes mode to pencil in candidate numbers without committing. Three difficulty levels are available: Easy, Medium, and Hard.
- Click / tap a cell to select it, then press a digit key or tap the number pad.
- Notes mode: tap the pencil icon to switch to candidate notation — mark multiple possible digits in a cell.
- Erase: press Backspace or tap 0 to clear a cell.
- Timer tracks how long you've been solving — try to beat your personal best.
Tips & Strategy
- Start with the most constrained cells. Look for rows, columns, or boxes that already have 7 or 8 digits filled in — the missing ones are forced.
- Scan for single candidates. If only one digit can legally go in a particular cell given the filled digits around it, place it immediately.
- Use box interactions. If a digit can only appear in one row within a 3×3 box, it can't appear elsewhere in that row outside the box.
- Pencil in candidates. Using notes mode to track possible digits for each cell makes it much easier to spot hidden singles and pairs.
About This Game
This Sudoku generates fresh puzzles at three difficulty levels and runs entirely in the browser with no downloads or sign-ups. Your solving time is tracked, but no data is sent anywhere. It's part of the free puzzle collection at Misunderstood Games.