Sudoku strategy
Hidden Singles Sudoku Strategy
Beginner technique Beginner
A hidden single appears when a digit can only fit in one cell within a row, column, or box, even if that cell has several candidates.
How to use it
- Pick a unit: one row, column, or 3x3 box.
- Pick a digit that has not been placed in that unit.
- Scan every empty cell in the unit and eliminate cells blocked by matching digits elsewhere.
- If one location remains, place the digit there.
Practice: Use the Human Solve button on Easy or Medium puzzles when you want to compare your scan with the next logical step.
Practice this strategy
Use the interactive solver to practice this technique on a fresh puzzle. If you get stuck, the Human Solve mode can show the next logical step.