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XYZ-Wing

When a three-candidate pivot works with two matching wings.

Explanation

An XYZ-Wing uses a pivot with candidates X/Y/Z and two two-candidate wings X/Z and Y/Z. Because Z must appear in the pivot or one of the wings, any other cell that sees all three source cells can remove Z.

XYZ-Wing example Sudoku board 2 1 8 4 5 7 9 5 9 1 2 4 8 6 4 3 9 8 7 5 1 6 2 1 2 6 7 5 8 9 3 4 6 8 2 5 9 6 1 3 8 2 4 4 2 9 7 8 2 6 4 9 3
An example board where XYZ-Wing applies

Practice tip

Start from cells with exactly three notes, then look for two peer cells whose two notes are contained inside the pivot notes.

Example steps

  1. Find a pivot cell with three candidates.
  2. Find two wings that each share two of those candidates.
  3. Remove the common candidate from cells that see the pivot and both wings.

Try this technique on a real puzzle.

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