Sudoku technique · First needed at: Expert
XY-Wing
Three linked cells force this number out of any cell two of them both see.
An example from a real puzzle
- The cells that make the pattern
- Candidates it removes
How to spot it
- Find a cell with exactly two candidates, X and Y: the pivot.
- Find two cells it sees: one with X and Z, one with Y and Z. These are the pincers.
- Any cell that sees both pincers cannot be Z.
Why it works
Whatever the pivot turns out to be, one of the pincers becomes Z — so a cell that sees both can never hold Z.
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