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Extreme Sudoku

Want to put your Sudoku solving skills to the ultimate test? Try our Extreme Sudoku!

What's Extreme Sudoku

Extreme Sudoku puzzles are designed for Sudoku enthusiasts familiar with advanced solving techniques. Playing Extreme Sudoku requires time, patience, and skills. You'll have to use pencil notes to solve Extreme Sudoku.

How to play Extreme Sudoku

Solving techniques

Unless you prefer the trial-and-error method, you need to learn some formal advanced techniques to play Extreme Sudoku.

The following advanced techniques are needed:

  • X-Wing
  • Swordfish
  • Skyscraper
  • 2-String Kite
  • XY-Wing
  • XYZ-Wing
  • W-Wing

Use pencil

Extreme Sudoku can't be solved without the use of pencil notes. Use pencil notes to maintain a list of feasible candidates in each cell.

Use hints

Use the hint function if you get stuck, don't guess. Hints will teach you, and soon you'll notice that your solving skills have improved. Hints for Extreme Sudoku require pencil notes to be filled in.

More tips

Read tips applicable to all levels of Sudoku, not just Extreme.