XY-Wing
Rated 4.8 on the technique scale · A pivot and two pincers.
Find a cell with exactly two candidates (the pivot), say 1 and 2, that sees two other two-candidate cells: one holding 1 and 3, the other holding 2 and 3. Whichever value the pivot takes, one of the pincers must be 3 — so any cell that sees both pincers cannot be 3.
XY-Wings are the gateway to the expert tier and are worth 4.8 points. They are also the point where most players start writing candidates down for every cell.
Longer chains of the same logic (XY-Chains) are worth 7.5 points and appear in the hardest puzzles.
XY-Wing — A pivot holding 3/5 sees two pincers 3/9 and 5/9, so 9 cannot be in any cell that sees both pincers.
Practice it: xy-wing shows up most often in hard and expert puzzles. Browse those levels →
How the rating uses it
When a puzzle cannot be finished with easier techniques, the solver applies XY-Wing and adds 4.8 to the puzzle's score. The hardest technique a puzzle needs decides its level, and puzzles with 26 clues or fewer move up one level.