An XY-wing whose pivot also holds the shared digit: it goes from cells that see all three.
What to look for
Find a pivot with three candidates, X, Y and Z, and two cells it sees with two candidates each, X and Z, and Y and Z. Then look at the cells that see all three of them, usually in the pivot’s box.
Why it works
Whatever the pivot is, Z ends up in one of the three cells: if the pivot is X or Y, a pincer is Z, and otherwise the pivot itself is. So a cell that sees all three cannot be Z.
Practise it
Puzzles that need it: Expert sudoku
On a real puzzle
XYZ-wing
One of these three cells must be 7, whichever way they go.
So 7 can go from the highlighted cells.
The cells that show the pattern are in amber, the cells it changes in green, and the candidates it removes are circled.
