Sudoku Solving Techniques - XYZ-Wing

This is a variation of an XY-wing. In the partial puzzle below, consider the cells that have only the candidates shown. Any cells that share a unit with all three cells XYZ, XY and YZ, can have Z eliminated from their candidates.

It can be easily seen that whichever value is in XYZ, the cell marked with the asterisk cannot be Z.

if XYZ = X, then XZ = Z, so * cannot be Z
if XYZ = Y, then YZ = Z, so * cannot be Z
if XYZ = Z, then * cannot be Z
This allows Z to be eliminated from the candidates for the marked cell.

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