Sudoku strategies
Move beyond basic scanning with a small set of reliable techniques that work across many Sudoku difficulty levels.
Try these strategiesSingles
A naked single is a square with only one possible candidate. A hidden single occurs when a digit has only one possible position within a row, column or box, even if that square has other pencilled candidates.
Candidate pairs
When the same two candidates occupy exactly two squares in one row, column or box, those digits must belong to those squares. They can therefore be removed from the other squares in that unit.
Work systematically
- Rescan after every confirmed placement.
- Keep candidate notes current.
- Compare intersecting rows, columns and boxes.
- Avoid guessing; switch to another area when stuck.