How to Play
How to Play Sudoku
Sudoku is a puzzle where you fill a 9×9 grid with the numbers 1 to 9. Every column, every row and every 3×3 box outlined in bold must contain each number exactly once. No maths needed — just logic and a little insight.
How to play Flow
1
Tap an empty square to select it. Its row, column and box are lightly highlighted.
2
Enter a number with the buttons. Every square with the same number lights up too.
3
Wrong numbers turn red and add to your miss count. Turn on “Notes” to pencil in candidates.
4
Fill every square correctly to win. Close the page midway and you can pick up where you left off.
Controls Controls
- Notes
- When on, numbers go in as small candidates. Press the same number again to remove it.
- Undo
- Takes back one move at a time, as far as you like.
- Erase
- Clears the number or notes in the selected square. Starting numbers can’t be erased.
- Hint
- Fills the selected square with the correct number — or a random empty square if none is selected.
- Levels
- Easy, Medium and Hard — harder puzzles start with fewer numbers. Every puzzle is generated fresh and always has exactly one solution.
Solving tips Tips
- Start with the rows, columns and boxes that are nearly full. With only one or two numbers missing, they often fall into place.
- If a number has only one possible spot within a box, that’s where it goes.
- If a square has only one candidate left, that’s the answer. Writing candidates with Notes makes these easier to spot.
- Placing a number automatically removes it from the notes in its row, column and box. Good note-taking makes Hard puzzles much easier.
Keyboard shortcuts (PC) Keys
Keys 1–9 enter numbers, arrow keys move, Backspace erases, M toggles Notes, Z undoes, H gives a hint and N starts a new game.