W-Wing

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A W-Wing is a mixed-digit alternating inference chain built from two bivalue cells and one conjugate pair. The two bivalue cells sit at the ends of the chain as the pincer cells, and they contain the same pair of candidates W and Z. If there is a conjugate pair for candidate W, and each end of that conjugate pair forms a weak link with candidate W in one of the pincers, then that conjugate pair acts as the pivot and creates a W-Wing. If candidate Z in another cell forms weak links with candidate Z in both pincer cells, it can be eliminated.

For example, in the board below, the pincer cells R1C2 and R8C8 both contain the same pair of candidates, 2 and 6. In row 5, there is a conjugate pair for candidate 2 at R5C2 and R5C8, which serves as the pivot. So we have a W-Wing with W=2 and Z=6. Candidate 6 in R1C8 forms weak links with candidate 6 in both pincer cells, so it can be eliminated.

Here are some more W-Wing examples.