Fill the 9x9 grid so every row, column, and 3x3 box contains digits 1-9.

Tap an empty cell to select it (highlighted in blue). Arrow keys also work.

Tap a number on the keypad, press keys 1-9, or drag a number onto a cell.

Toggle Notes (or press N) to write small candidate numbers in a cell.

Wrong entries are highlighted in red and counted, but the game never ends. Just fix them.

Use hints to reveal the correct number for a cell. You have 3 hints.

Undo your last move (U) if you made an error.

Tap the expand icon on the main menu to play fullscreen on any screen size.