Techniques
Solving techniques
Every step in our walkthroughs names its technique. These pages explain each one in a sentence and link to real puzzles from the books where it is the move that unlocks the grid. The hard ones are what our books are made of: hard sudoku techniques and hard killer sudoku techniques.
Sudoku techniques
- Naked Singles in 450 walkthroughs
- Hidden Singles in 450 walkthroughs
- Naked Pairs/Triples in 428 walkthroughs
- Hidden Pairs/Triples in 158 walkthroughs
- Naked/Hidden Quads in 2 walkthroughs
- Pointing Pairs/Triples in 445 walkthroughs
- Box-Line Reduction in 311 walkthroughs
- X-Wing/Swordfish in 180 walkthroughs
- Skyscraper in 152 walkthroughs
- 2-String Kite in 290 walkthroughs
- Empty Rectangle in 199 walkthroughs
- XY-Wing in 236 walkthroughs
- XYZ-Wing in 137 walkthroughs
- W-Wing in 247 walkthroughs
- Unique Rectangles in 12 walkthroughs
- BUG+1 in 3 walkthroughs
- Jellyfish in 8 walkthroughs
- Finned Fish in 394 walkthroughs
- XY-Chain in 439 walkthroughs
- WXYZ-Wing in 376 walkthroughs
- Sue de Coq in 174 walkthroughs
- Coloring/Multi-coloring in 37 walkthroughs
- ALS-XZ in 450 walkthroughs
- Nice Loops/AICs in 443 walkthroughs
- Cell Forcing Chains in 337 walkthroughs
Killer sudoku techniques
- Naked Singles in 450 walkthroughs
- Hidden Singles in 450 walkthroughs
- Naked Pairs/Triples in 450 walkthroughs
- Hidden Pairs/Triples in 320 walkthroughs
- Naked/Hidden Quads in 135 walkthroughs
- Pointing Pairs/Triples in 442 walkthroughs
- Box-Line Reduction in 403 walkthroughs
- X-Wing/Swordfish in 14 walkthroughs
- Skyscraper in 77 walkthroughs
- 2-String Kite in 88 walkthroughs
- Empty Rectangle in 104 walkthroughs
- XY-Wing in 55 walkthroughs
- XYZ-Wing in 57 walkthroughs
- Remote Pairs in 221 walkthroughs
- Finned Fish in 108 walkthroughs
- WXYZ-Wing in 4 walkthroughs
- Sue de Coq in 18 walkthroughs
- Coloring/Multi-coloring in 279 walkthroughs
- Cage Sum Arithmetic in 450 walkthroughs
- Cage Combination Limits in 450 walkthroughs
- 45-Rule (Box/Row/Column) in 388 walkthroughs
- Virtual Cages in 450 walkthroughs
- Cage Min/Max Bounds in 449 walkthroughs
- Innies & Outies in 114 walkthroughs
- Forced Cage Splits in 450 walkthroughs
- Multi-Sector Locking in 346 walkthroughs
- Advanced Innies (3+ sectors) in 345 walkthroughs
- Forcing Chains in 436 walkthroughs
Why some grids are so much harder than others, and the toughest puzzles in our books: hard sudoku · hard killer sudoku.
Wordsearch has no techniques to name, but ours is a different beast: see the five-letter wordsearch.