Sudoku is a logic puzzle played on a 9×9 grid. Fill every row, every column, and every 3×3 box with the digits 1 through 9 — each digit exactly once per row, column, and box.

Tap a cell to select it, then pick a digit from the keypad or press a number key on your keyboard. Use pencil marks to jot down candidates you aren't sure of yet. Undo freely — nothing is final until the grid is complete.

You have three lives per puzzle. A wrong placement costs one life. Run out and you can watch a short video to continue, or start a brand-new puzzle from the Start Over option.

Easy puzzles are the best place to start — cells contain more starting digits than medium or hard, so a beginner can see a path forward without techniques beyond basic scanning.

Playing Sudoku regularly helps train concentration and working memory. A few easy puzzles a day is enough to notice your scanning speed improve over a couple of weeks.