XYZ-Wing

XYZ-Wing is a close cousin of Y-Wing. The pivot now has three candidates {X, Y, Z}. The two wings are bivalue: {X, Z} and {Y, Z}, and both are peers of the pivot.

Z must end up in one of the three cells (pivot or either wing). So any cell that sees all three can't be Z. The elimination pool is smaller than Y-Wing — only cells that see every wing AND the pivot — but the pattern is otherwise the same.

When to look for it

Spot a trivalue cell that's a peer of two bivalue cells whose candidates together cover the pivot's three.

How to apply it

1. Find a trivalue cell P with candidates {X, Y, Z}.
2. Find peers W1 = {X, Z}, W2 = {Y, Z}.
3. Z can be removed from cells that see all three (P, W1, W2).

Example