Find a cell with only two options, x or y: the pivot. If it sees one cell that can only be x or z and another that can only be y or z (the pincers), then whichever the pivot is, one of the pincers becomes z. So no cell that sees both pincers can be z.
XY-Wing is the first technique here that works with several digits at once. All it needs is three cells with exactly two candidates each.
It is also called a Y-Wing. Once you start looking at the cells with two candidates, it turns up surprisingly often in hard puzzles.
An XY-Wing
The pattern
Candidates removed
Solved as a result
R6C3 can only be 4 or 7. If it is 4, then R6C6 (only 4 or 2) must be 2; if it is 7, then R9C3 (only 7 or 2) must be 2. Either way one of them is the 2, so the 2 can be removed from every cell that sees both: R9C6. That leaves R9C6 with only one candidate: 8.
This position comes from a puzzle generated on this site, after every single has been filled in. Boxes are numbered 1–9 from the top left, row by row; R5C4 means row 5, column 4.
How to spot it
1Fill in the candidates and look for cells that have exactly two.
2Pick one as the pivot; say it can be x or y.
3Find a cell the pivot sees that can only be x or z, and another it sees that can only be y or z. The z has to be the same digit in both.
4Remove z from every cell that sees both pincers.
Why it works
If the pivot is x, the x/z pincer can't be x, so it is z. If the pivot is y, the y/z pincer is z.
The pivot must be one of the two, so one pincer is always z.
A cell that sees both pincers would clash with whichever one is z.
Common mistakes
Pincers that don't see the pivot. Each pincer must share a row, column or box with it.
A cell with three candidates. All three cells need exactly two.
Removing z from cells that see the pivot instead of both pincers. The pivot never holds z.
Questions
Is XY-Wing the same as Y-Wing?
Yes, they are two names for the same pattern.
Do the pincers have to see each other?
No. Usually they don't; the eliminations are in the cells that see both of them.
What comes next?
XYZ-Wing lets the pivot have a third option: z itself.
We use one strictly necessary cookie to keep you signed in, and your browser's local storage to save game progress (your puzzles and best times) on this device. Analytics runs cookie-free by default — accepting lets us measure visits in more detail.