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
Find a cell with exactly two candidates. Look for two other bi-value cells, each sharing a row, column, or box with it, such that one digit overlaps with the pivot and a third digit is common to both wings. The Z digit is forbidden in any cell that both wings can see.
1
2
2
5
5
5
1
5
5
Worked example
Pivot {1,2} at the center; wing {2,5} on the right; wing {1,5} below. Any cell seen by both wings cannot be 5.
Time to practice
Reading is half the work. Try a puzzle now and look for the techniques you just learned.