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Sudoku Puzzle Generator

Create a classic 9×9 Sudoku with a verified unique solution, then solve it here.

Create New Puzzle

How Puzzle Generation Works

🎲 Generation Algorithm

  • Step 1: Create a complete valid Sudoku solution using backtracking with randomized digit order
  • Step 2: Remove numbers strategically in random order
  • Step 3: Verify each removal maintains a unique solution
  • Step 4: Keep extra clues if removing one would create multiple solutions

📊 Difficulty Levels

  • Easy: 40-45 given numbers
  • Medium: 30-35 given numbers
  • Hard: 25-30 given numbers
  • Expert: Targets 22-25 given numbers and may retain more to preserve uniqueness (generator-only)

✓ Quality Guarantees

  • ✓ Every puzzle has exactly one unique solution
  • ✓ Every puzzle is verified solvable
  • ✓ A complete solution is retained for validation
  • ✓ Difficulty is currently estimated from clue count

⚡ Performance

  • • Generated locally on demand in your browser
  • • Uses randomized backtracking
  • • Does not select from the static puzzle collection
  • • Does not create a public puzzle URL