Classic Sudoku
Classic Sudoku is the familiar 9×9 puzzle with nine rows, columns and boxes.
Classic Sudoku
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Keyboard: 1–9 enter · arrows move · N notes · Backspace clear · Ctrl+Z undo
How to Play Classic Sudoku
- Fill every empty cell with a digit from 1 to 9.
- Each row, column and 3×3 box must contain each digit exactly once.
Tips for Solving
- Start with a row, column or box that already contains many numbers.
- Use notes to track possible digits, then look for a digit that fits only one cell.
- Recheck nearby rows, columns and boxes after each placement.
Frequently Asked Questions
Is Classic Sudoku free to play?
Yes. Every Classic Sudoku puzzle on Sudoku Shrine is free in your browser, with no account or download.
Does every Classic Sudoku puzzle have one solution?
Yes. Each puzzle is checked by a solver so it has exactly one solution and can be solved by logic alone.
Which difficulty should I start with?
Start with Easy to learn the layout, then move to Medium and Hard once scanning and notes feel natural.
Is my progress saved?
Yes. Your entries and notes are saved in this browser, so you can close the page and continue later.