Sudoku - How to Play

Keyboard instructions

Moving around the grid

Click on a cell to select that cell. Use the arrow keys to move around the grid.

Use the arrow keys to move around the grid. Navigation with the arrow keys wraps around the grid - so, for example, pressing the "down" arrow when already at the bottom of the grid will jump you back to the top of the grid. You can also navigate using the keys WASD if you prefer.

Click-and-drag to select multiple cells, or hold down the Control key when clicking to add to the current selection. You can also hold down the Control key when using keyboard navigation to add cells to the selection.

Entering numbers into the grid

Use the keys 1-9 to enter numbers into the grid.

If your keyboard has a numpad, you can use either set of number keys.

To remove a value from a cell, use the Backspace or Delete keys.

Changing mode

There are four modes for entering values into the grid:

  • Normal - enters large numbers into the cells
  • Corners - enters small numbers into the corners of the cells
  • Centre - enters small numbers into the centres of the cells
  • Highlight - used to highlight cells in a particular colour

You can switch to any of one these modes using the shortcut keys Z, X, C and V respectively.

You can also temporarily enter Corners mode by holding down the Shift key, and Centre mode by holding down the Control key. When you release the key you will be returned to the previous mode.

Finally, you can cycle through all four modes in turn by pressing the Spacebar.

Undo / Redo

You can undo your previous actions by pressing Control+Z.

Similarly, you can redo previously-undone actions with Control+Y.

If everything goes terribly wrong, you can start from scratch with the "Restart" button.

When you're finished

When you've solved the puzzle, press the "Check" button. This will check the puzzle for any mistakes.

For the time being, puzzles that are uploaded to the website do not have saved solutions, so the "Check" button only looks for repeated numbers in rows, columns and regions - it doesn't understand any additional rules.

This means that if the button thinks you have solved the puzzle correctly, you still need to make sure of any additional constraints yourself!

Touchscreen instructions

Moving around the grid

Tap on a cell to select that cell for use. You can drag across multiple cells to select them all.

Entering numbers into the grid

Use the buttons labelled 1-9 to enter numbers into the grid.

To remove a value from a cell, use the Delete button.

Changing mode

There are four modes for entering values into the grid:

  • Normal - enters large numbers into the cells
  • Corners - enters small numbers into the corners the cells
  • Centre - enters small numbers into the centres of the cells
  • Highlight - used to highlight cells in a particular colour

You can cycle between these modes using the buttons labelled with each mode.

Undo / Redo

You can undo your previous actions using the Undo button, and redo previously-undone actions with the Redo button.

If everything goes terribly wrong, you can start from scratch with the "Start Over" button.

When you're finished

When you've solved the puzzle, press the "Check" button. This will check the puzzle for any mistakes.

For the time being, puzzles that are uploaded to the website do not have saved solutions, so the "Check" button only looks for repeated numbers in rows, columns and regions - it doesn't understand any additional rules.

This means that if the button thinks you have solved the puzzle correctly, you still need to make sure of any additional constraints yourself!