How to read the grids
- Given - clues from the starting puzzle
- Subject - cells the technique focuses on
- Eliminated - candidates this technique removes
- Candidate - pencil marks shown for reference
How to spot it
Pick a digit. For each row, column, and box that does not yet contain it, ask: how many empty cells could legally hold it? If the answer is one, place it.
7
7
3
5
1
7
4
7
9
6
7
7
Worked example
In the highlighted box, the digit 7 has only one cell where it can legally land - the others are blocked by a 7 in their row or column. Place 7 there even if that cell has other candidates.
Time to practice
Reading is half the work. Try a puzzle now and look for the techniques you just learned.