Sudoku Flow is a clean take on the classic 9x9 number puzzle. You fill every row, column and 3x3 box with the digits 1 to 9, using the given clues as your starting point. Beyond the basic puzzle, it adds pencil notes, a three-level hint system, several game modes and a short lessons section on solving techniques.
How to Play Sudoku Flow
Select an empty cell and enter a digit with the number pad or your keyboard. Each digit may appear only once in its row, its column and its 3x3 box. Gray cells hold the starting clues and cannot be changed.
When a number clashes with another digit in the same row, column or box, the clashing cells flash, and a wrong entry adds one to your mistake counter. Use Notes mode to jot small candidate digits in a cell while you work things out.
Open New Game to choose a difficulty. Easy starts with 36 to 40 clues, while Insane gives only 17 to 21, and Custom lets you set the clue count with a slider. You can also pick a mode: Classic, Timed Rush, Zen, Hardcore or Infinite, where a new puzzle starts by itself after each solve. The Daily Challenge serves one medium puzzle per calendar date.
Your score starts at 2,000. You lose 100 points per mistake, 50 per hint and one point for every ten seconds.
Sudoku Flow Controls
| Action | Keyboard | Mouse | Touch |
|---|---|---|---|
| Select a cell | Arrow keys | Click a cell | Tap a cell |
| Enter a number | 1 to 9 | Click a button on the number pad | Tap a button on the number pad |
| Clear a cell | Backspace or Delete | Click "Erase" | Tap "Erase" |
| Switch pencil notes on or off | N | Click "Notes" | Tap "Notes" |
| Get a hint | H | Click "Hint" | Tap "Hint" |
| Undo or redo | Ctrl+Z, or Ctrl+Y | Click the arrow buttons in the top bar | — |
| Pause | P | Click the pause button | — |
| Show all shortcuts | ? | — | — |
Tips and Strategies
- Hunt for singles first. Look for a row, column or box that is missing only one or two digits, and fill those before anything harder.
- Scan one digit at a time. Pick a number, say 7, and check each box for the one spot where it can still go.
- Use notes on harder grids. On Expert and Insane, pencil in candidates so pairs and patterns stand out.
- Lean on the highlights. Selecting a filled cell lights up every matching digit on the grid.
- Save hints for real dead ends. Each one costs points and time, so try a Level 1 hint before you reach for a full answer.
- Read the Learn lessons. They cover naked and hidden singles, naked pairs, pointing pairs, X-Wing and Swordfish.
Features
- Five set difficulties plus Custom: from Easy to Insane, or any clue count from 17 to 50.
- Six game modes: Classic, Timed Rush, Zen, Hardcore, Infinite and the Daily Challenge.
- Progress tracking: best times, a daily streak, achievements and an archive of solved puzzles, all kept in your browser.
- Six color themes: Light, Dark, Cream, Paper, Forest and Midnight.
- Undo and redo: step back through your moves at any point.
Tested and updated:
