The Y-Wing (XY-Wing) Technique in Sudoku
The Y-Wing, also known as the XY-Wing, is the classic short-chain technique. It uses a pivot cell with two candidates and two “pincer” cells that, between them, force a digit out of any cell they both see. Once you can read it, a whole class of hard eliminations opens up.
How to use the Y-Wing, step by step
- Find a pivot cell with exactly two candidates — call them X and Y.
- Find one pincer the pivot can see with candidates {X, Z}, and another it can see with {Y, Z}.
- Note the shared third digit Z that both pincers carry.
- Find cells that can see both pincers at once.
- Eliminate Z from those cells — whichever way the pivot resolves, one pincer becomes Z.
- Re-scan for the singles this opens up.
What is a Y-Wing?
A Y-Wing is three bi-value cells: a pivot {X, Y}, a pincer {X, Z} and a pincer {Y, Z}. If the pivot is X, the first pincer must be Z; if the pivot is Y, the second pincer must be Z. Either way a Z appears in one pincer, so any cell seeing both pincers cannot be Z. “Y-Wing” and “XY-Wing” are two names for this same pattern.
How to spot a Y-Wing
Hunt among bi-value cells: pick one as the pivot and look in its peers for two more bi-value cells that share the pivot’s digits and a common third digit Z. The pivot must see both pincers; the pincers need not see each other. The bigger cousin, the XYZ-Wing, gives the pivot three candidates instead of two. See the full ladder in tips & strategy.
Y-Wing in Sudoku: FAQ
What is a Y-Wing in Sudoku?
A Y-Wing is a three-cell technique with a two-candidate pivot {X, Y} and two pincer cells {X, Z} and {Y, Z}. One of the pincers is always forced to Z, so any cell that sees both pincers can have Z removed.
Is the Y-Wing the same as the XY-Wing?
Yes. “Y-Wing” and “XY-Wing” are two names for exactly the same pattern: a bi-value pivot with two bi-value pincers sharing a third digit. The XYZ-Wing is the related but different move where the pivot has three candidates.
How do you spot a Y-Wing?
Work among bi-value cells. Choose a pivot {X, Y}, then look in its row, column and box for one cell {X, Z} and one cell {Y, Z}. If a cell elsewhere can see both pincers, remove Z from it.