Free online Sudoku

Classic Sudoku Rules

Build your Sudoku skills with clear rules, visual examples, technique walkthroughs, and a short history of the puzzle.

  • Understand rows, columns, 3x3 boxes, candidates, and valid moves.
  • Study beginner, intermediate, and advanced solving techniques.
  • See worked examples that explain why each logical step is valid.
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Sudoku rules and solving techniques