Controls
You can play entirely by tapping, entirely by mouse, or entirely from the keyboard. Select a cell, then enter a digit from the pad or the keyboard. Switch on Notes with the button or the N key to write pencil marks, and double-tap a digit on the pad for digit-first entry.
The keyboard uses arrow keys to move, the digits to enter, Backspace to erase, Ctrl or Command with Z to undo, H for a hint and P to pause. This page lists every control and setting.
How do you play with a mouse or touchscreen?
Click or tap a cell to select it. Then click or tap a digit on the pad below the grid to enter it. If Notes is on, the digit is added to or removed from the cell’s pencil marks instead. Entering a value in a cell that holds marks replaces them. Given digits are locked and cannot be changed.
Digit-first entry
Digit-first mode reverses the order of the two taps. Double-click or double-tap a digit on the pad to arm it, and the button lights up. Every cell you then tap receives that digit, as a value or as a note depending on whether Notes is on. Tap the lit digit again to switch the mode off, or tap another digit to arm that one instead. Holding Shift while clicking a pad digit arms it too. This suits placing the same digit in several cells in a row.
Scrolling and zooming
The grid is set up so quick taps do not trigger the browser’s double-tap zoom, and the page below the game scrolls as normal. No pinch or long-press gesture is needed to play.
What is the keyboard map?
The grid is a single stop in the Tab order. Once it has focus, the arrow keys move between cells, and a visible focus ring shows where you are. Shortcuts do not fire while a dialog such as Settings is open.
| Key | Action | Notes |
|---|---|---|
| Arrow keys | Move to the next cell | Up, down, left and right |
| 1 to 9 | Enter a digit in the selected cell | Adds a note instead if Notes is on |
| A to G | Enter the symbols 10 to 16 | 16×16 board only |
| N | Switch Notes on or off | The button shows “Notes: on” or “Notes: off” |
| Backspace or Delete | Erase the selected cell | Clears its value and its notes |
| Ctrl or Command + Z | Undo | Covers values and notes |
| Ctrl or Command + Shift + Z | Redo | |
| H | Hint | Not available in expert mode |
| P | Pause or resume | The grid is hidden while paused |
| Shift + N | New puzzle | Not available in expert mode or the daily puzzle |
The Keys button in the toolbar opens the same list in a dialog while you play.
What do the toolbar buttons do?
| Button | What it does | Where it appears |
|---|---|---|
| Undo, Redo | Step backwards or forwards through your moves | Everywhere |
| Erase | Clears the selected cell | Everywhere |
| Notes | Switches pencil-mark entry on or off | Everywhere |
| Auto-notes | Fills candidate notes in every empty cell from the digits placed so far | All except expert mode |
| Hint | Gives a hint in up to three levels | All except expert mode |
| Check | Flags any wrong digits on the board | All except expert mode |
| New | Loads a different puzzle at the chosen level | Not in expert mode or the daily puzzle |
| Restart | Returns the current puzzle to its starting position | Not in expert mode |
| Pause | Hides the grid and stops the timer | Everywhere |
| Stats | Shows your results for each level | Everywhere |
| Settings | Opens the settings dialog | Everywhere |
| Keys | Shows the keyboard shortcuts | Everywhere |
How do hints work?
Each press of Hint on an unchanged board moves to the next level.
- Where to look. The hint highlights the cells or the house involved.
- Which technique. The hint names the technique that applies, such as hidden single or pointing pair.
- The move. The hint gives the digit to place or the candidates to remove, with an Apply button. Nothing changes on the board until you press Apply.
Hints are worked out from the digits currently placed on the board. They ignore your pencil marks and never read the stored solution. If no named technique applies, the hint says so and offers to reveal one cell. A hint counts towards the hints shown when you finish. The grading guide describes the solver behind them, and each technique has a lesson in the techniques hub.
What can you change in the settings?
| Setting | Options | Default |
|---|---|---|
| Mistake feedback | Instant, Off, or Strict (three mistakes ends the game) | Instant |
| Remove notes automatically when placing a digit | On or off | On |
| Highlight row, column and box | On or off | On |
| Highlight matching digits | On or off | On |
| Show timer | On or off | On |
| Large digits | On or off | Off |
| Left-handed pad layout | On or off | Off |
| Sound effects | On or off | Off |
| Theme | Match device, light or dark | Match device |
| Colors | Default or colorblind-safe | Default |
| Animation | Full, reduced or off | Full |
Settings are saved in your browser. If the browser blocks storage, they last until you close the page.
What accessibility features are there?
- Full keyboard play. Every action that a pointer can perform has a keyboard equivalent, and the focus ring is always visible.
- Screen reader support. The grid is exposed as a grid. Each cell is announced with its position and contents, for example “row 3, column 5, empty, notes 2 4 7”. A live region announces placed digits, notes added or removed, conflicts, hints, pauses and completion.
- No color-only meaning. Matching digits are underlined, conflicts have a wavy underline and an exclamation mark, and wrong digits carry the same mark, in addition to color.
- Colorblind-safe palette, large digits and dark theme are in the settings.
- Reduced motion. The Animation setting can reduce or switch off movement, and the game also follows your device’s reduced-motion preference.
The game has been tested with automated browser tests, but not yet with a range of real screen readers and assistive devices, so please tell us about problems you find.
What is saved, and where?
When you switch tabs or apps, the game pauses and saves the board in your browser. Statistics, such as games played, games won, best time and fewest hints for each level, are stored only in your browser as well. They do not follow you to another device, and clearing site data removes them. More on how the site handles data is in the privacy policy.
How does this differ in the daily puzzle and expert mode?
The daily puzzle has no New button, because everyone plays the same board for the day. Expert mode removes New, Restart, Hint, Auto-notes and Check and turns off mistake feedback, so it relies on your own checking. The rules for both are on the rules page. For tips on playing on a phone, see Sudoku on mobile.