How to play
Fill the grid so that every row, every column and every box holds each digit exactly once. On a classic grid, that means 1 to 9 in each of the nine rows, nine columns and nine 3×3 boxes.
Your first grid
A small one to start: each row, column and 2×2 box takes 1, 2, 3 and 4. Tap a cell, then a digit.
Notes
Not sure yet? Turn on Notes, or hold Shift while typing, and digits go in small, as reminders of what a cell could be. A digit you place leaves the notes of the cells it sees.
Hints
Stuck? Hint shows where to look. Press it again for the full reasoning, with the same techniques as the lessons.
Mistakes
Place a digit that is already in its row, column or box and both turn red: that counts as a mistake. Nothing else is checked as you go. The daily puzzle marks nothing at all: the grid is only checked once it is full, and each failed check counts.
Which level to start with
New to sudoku? Start with Easy. Each level needs new techniques:
- Easy
- Spot the one place each digit fits.
- Medium
- Count what is left in a cell.
- Hard
- Pairs and triples.
- Expert
- X-wings and wings.
- Master
- Chains and coloring.
Keyboard
- ← ↑ → ↓
- Move around the grid
- 1 to 9
- Place a digit
- Shift + 1 to 9
- Add or remove a note
- N
- Notes on or off
- Backspace, Delete or 0
- Erase
- H
- Hint
- Ctrl + Z, Ctrl + Y
- Undo, redo