XYZ-Wing
Like XY-Wing, but the pivot keeps a third candidate, which tightens where the elimination applies.
How it works
- 1A1 is the tri-value pivot, {1, 2, 3}. A2 shares its column and holds {1, 3}; D1 shares its row and holds {2, 3}.
- 2The two wings share no unit with each other, so pivot and wings never sit in one unit together — there is no Naked Triple hiding under this.
- 3If A1 is 3 we are done. If A1 is 1, A2 must be 3; if A1 is 2, D1 must be 3. One of the three always holds it.
- 4Because the pivot itself could be the 3, only a cell seeing all three counts. B1 does — A1 and D1 along row 1, A2 through the box — so its 3 goes.
- Cells that establish the pattern
- Where the conclusion lands
- Candidate ruled out