Three rules. One complete grid.
The heavier lines divide the board into nine smaller 3 by 3 boxes. Every square belongs to one row, one column and one box. A completed puzzle must satisfy all three rules at once.
- Each row contains every digit from 1 to 9 exactly once.
- Each column contains every digit from 1 to 9 exactly once.
- Each 3 by 3 box contains every digit from 1 to 9 exactly once.
- The numbers already printed on the board are fixed clues. You cannot change them.
Find a first move you can explain.
Start with a row, column or box that is nearly full. If a row contains 1, 2, 3, 4, 5, 6, 8 and 9, its last square must be 7. Check that square’s column and box too: every placement must agree with all three groups.
When several squares are empty, compare their possibilities. Suppose a row is missing 2 and 7. If one empty square sits in a column that already contains 2, that square must be 7. The other empty square in the row is then 2. This is the kind of elimination that builds a solution.
Use notes for possibilities.
Select an empty square and turn on Notes to record small candidate digits. A candidate is a number that does not already appear in that square’s row, column or box. Notes are working marks, not answers, so keep them up to date as the board changes.
For a final answer, turn Notes off and enter one digit. In Sudoku Dawn, placing a digit also removes that digit from notes in related squares. Undo restores your previous entry and notes together. You can erase an editable square without changing the original clues.
Choose a comfortable way to play.
Tap a square, then choose a number on the keypad. On a keyboard, use 1–9 to enter digits, the arrow keys to move, N for Notes and Ctrl or Cmd plus Z to undo. Backspace or Delete erases. These shortcuts work while your focus is inside the game.
Settings also offers Number-first entry: choose a digit, then tap the squares where you want to place it. Focus mode gives the board more room. You can hide the timer if you prefer; elapsed playing time still records in your local results.
Get help without losing the reasoning.
Hint first points you toward a square. Choose Explain the move to see a supported deduction, then decide whether to place the number. The coach explains naked singles and hidden singles. When it cannot explain the next step, or finds an incorrect entry, it clearly offers an answer reveal instead.
Check highlights incorrect entries. A board without duplicate digits is not necessarily correct, and the progress bar counts filled squares rather than verified answers. Start on Easy, take one justified step at a time, and move up when you want a different challenge.