Sudoku Assistant - The Sudoku Trainer and Solver

Solving Sudoku Puzzles

This page links to discussions of the main techniques that you can use to solve Sudoku puzzles. You may find it helpful to refer to our Glossary if you are not familiar with some of the terminology that we use.

  1. Cross-Hatching the puzzle (Hidden Single);
  2. Counting 1-9 (Naked Single);
  3. Cross-Hatching 2;
  4. Pencil Mark techniques;
  5. Row and Column Limits;
  6. Block Interaction;
  7. N-possible (Naked Subset);
  8. Hidden Subset;
  9. X-Wing;
  10. Swordfish;
  11. Cell Colouring;
  12. Forcing Chains;
  13. Trial and Error.

There are many other obscurely named techniques for finding solutions to Sudoku puzzles. We have found that several of the ones above are excellent tools for the human solver, although some of the later options (particularly past 9) really do make for a complicated puzzle!

Although we have also documented the trial-and-error approach - we would generally consider that if this technique is necessary the puzzle is not well set for a human!

If you are unsure of any of the terminology we use, you may find it helpful to refer to our Glossary.

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