Master pencil mark strategies like Snyder Notation with visual diagrams. Keep your Sudoku board clean and spot Locked Candidates and Pairs instantly.
As Sudoku puzzles reach Medium, Hard, and Expert difficulty, holding candidate possibilities in your head becomes impossible. However, filling every single empty cell with 5 or 6 tiny candidate digits right from the start creates visual noise that hides simple moves. Here is how top solvers manage pencil marks in two distinct phases.
Named after World Sudoku Champion Thomas Snyder, Snyder Notation follows one strict rule during the early and middle stages of a puzzle:
Only write a candidate note inside a 3×3 box when that digit can go into EXACTLY TWO cells in that box. If a digit could go into 3 or more cells in a box, write nothing yet!
| 1 | 7 | 7 |
| 3 9 | 5 | 8 |
| 3 9 | . | 2 |
Why is Snyder Notation so powerful?
3 9 above), you immediately spot a Naked Pair / Hidden Pair.7 in Row 1), you immediately see a Pointing Locked Candidate.When Snyder Notation no longer yields placements on Hard or Expert grids, add candidates to cells that have only 2 or 3 possibilities along rows and columns, and finally fill in full candidates to search for X-Wing, XY-Wing, and Swordfish patterns.