XYZ-Wing

Level: first needed in Extreme puzzles. In one line: Like an XY-Wing, but the pivot also holds Z; removals happen in cells that see all three.

An XYZ-Wing is an XY-Wing whose pivot has three candidates, {X, Y, Z}, while the pincers are {X, Z} and {Y, Z}. Whatever the pivot becomes, Z ends up in the pivot or in one of the pincers.

So a cell that sees all three cells (the pivot and both pincers) cannot be Z. Because it must see the pivot too, the cells you can clear are usually in the pivot's box, next to one of the pincers.

Example from a real puzzle

This position comes from an Extreme puzzle in Sudoku Arena, at the exact moment the XYZ-Wing is the next logical move. Cells are named by row and column: R3C4 means row 3, column 4.

XYZ-Wing with pivot R8C4 removes 5. Result: remove 5 from R8C5.

Play this puzzle and look for the move yourself. It's a practice game, so it doesn't count towards your stats.

How to spot it

1. Find a cell with exactly three candidates {X, Y, Z}.
2. Look for two cells it sees, with {X, Z} and {Y, Z}.
3. Remove Z from any cell that sees all three.

Tips

• It removes fewer candidates than an XY-Wing, but it appears in some of the hardest puzzles.
• If you know XY-Wings, an XYZ-Wing is one small step further.

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