Sudoku Rules & Solving Techniques
Ten techniques - From the simplest single-cell fills to the advanced multi-row patterns used in Expert and Extreme puzzles. Learn them in order: each one builds directly on the last.
New to Sudoku? Start with How to Play →
Want a guided path? How to Solve Sudoku →
Strategy and tips in solving order - from your first scan to X-Wing - with links to every technique below.
Unsure what a term means? Look it up in the Sudoku Glossary.
Which Techniques Do You Need?
| Technique | Easy | Med | Hard | Expert | Master | Extreme |
|---|---|---|---|---|---|---|
| Last Free Cell | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Last Remaining Cell | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Last Possible Number | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Notes in Sudoku | – | ✓ | ✓ | ✓ | ✓ | ✓ |
| Obvious Singles | – | ✓ | ✓ | ✓ | ✓ | ✓ |
| Obvious Pairs | – | – | ✓ | ✓ | ✓ | ✓ |
| Hidden Singles | – | ✓ | ✓ | ✓ | ✓ | ✓ |
| Hidden Pairs | – | – | ✓ | ✓ | ✓ | ✓ |
| X-Wing | – | – | – | ✓ | ✓ | ✓ |
| Swordfish | – | – | – | – | ✓ | ✓ |
Beginner Techniques
4 techniquesEasy puzzles only. Master these four and you can complete any Easy puzzle in minutes.
Intermediate Techniques
3 techniquesRequired from Medium upward. These three techniques are the backbone of regular Sudoku play.
Advanced Techniques
3 techniquesExpert and above. Pattern-recognition techniques that operate across multiple rows and columns simultaneously.
Recommended Learning Order
Technique Frequency Across All Levels
Approximate share of total moves made using each category:
Basic elimination (Beginner)62%
Singles & pairs (Intermediate)29%
Fish patterns (Advanced)9%
Practice Recommendations
- Read the technique - Then immediately play a puzzle at that level
- Solve 3–5 puzzles per level before advancing
- Use Notes mode from Medium onward - It's not cheating, it's correct technique
- Use the Sudoku Solver to verify your completed puzzles
- The Daily Challenge reinforces whichever level you're practicing
Ready to apply what you've learned?
Pick the difficulty that matches your current technique level and put it into practice.