How to play
Understand Sudoku
You do not need maths knowledge, just a close look at the numbers.
The three rules
Fill in 1 to 9 so each number appears once in each row, column and 3 × 3 box. The given numbers stay in place.
Find your first move
Look for a row with many given numbers. Which number is missing? Check the column and box of an empty square. If only one number fits, enter it.
Controls and help
Choose an empty square, then a number. Notes hold possibilities. Explain a move shows a next step or, if you ask, a correction; Undo takes back your last move.
Pause and return
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