My Sudoku

Hard Used from hard puzzles up.

XY-Wing

A pivot and two wings

Take a cell with two candidates, X and Y: the pivot. Find two cells it sees: one with X and Z, the other with Y and Z. These are the wings.

If the pivot is X, the first wing is Z; if it is Y, the second wing is. Either way, one of the wings holds Z.

So a cell that sees both wings cannot be Z: remove it there.

What to look for

Find a two-candidate cell that sees two other two-candidate cells sharing one digit.

Example

13528942791279236789134726919812692354759694726893267952447814635591239837237891724236523472356458193456918691834725656372569169451485682184158567167913356 112233445566778899
XY-Wing: pivot R7C9 {5,6} with wings R2C9 {5,9} and R7C3 {6,9}; one wing must be 9, so remove 9 from R2C3.
  • The cells the technique relies on
  • Cells where it removes candidates, struck out in red

Practise it

In the app, Learn › XY-Wing sets exercises on real positions, then a full puzzle that needs this technique and nothing harder.

Practise in your browser