Box Brain Sudoku
Learn › XY-Wing
Hard · technique 16 of 18
XY-Wing
A pivot with candidates XY sees two pincers, XZ and YZ. Also called a Y-Wing.
How it works
Whichever digit the pivot takes, one pincer becomes Z. Any cell that sees both pincers cannot be Z.
A worked example
XY-Wing: the pivot in row 7, column 9 (3/7) with wings in row 6, column 9 and row 7, column 2 forces 5 out of cells seeing both wings.
- The cells that make the pattern
- Candidates it rules out
A real position from a puzzle in the app. Small digits are the candidates the step looks at; coloured digits are already solved.
Practise it in Box Brain Sudoku
The app teaches XY-Wing on this same board, then hands you puzzles that need it. When you are stuck mid-game, a hint first points you to the right area, then names the technique and shows the move.