XYZ-Wing: make all three cells share one digit
An XYZ-Wing uses an XYZ pivot with two wings XZ and YZ. Both wings see the pivot, and all three cells contain Z.
Key idea
At least one of the three pattern cells must be Z, so Z can be removed from any cell that sees all three.
See the move, step by step
Build a 6/7/8 XYZ-Wing across row 1 and box 1.
Step 1 of 4
Start from a three-candidate pivot
R1C1 contains 6, 7, and 8. Look for two peers that each hold Z plus one other pivot digit.
Step 2 of 4
Match the two wings
R1C4 is 6/7 and R2C2 is 7/8. Candidate 7 appears in the pivot and both wings. The wings do not see each other.
Step 3 of 4
Use the common peer intersection
If the pivot is 6, R1C4 must be 7; if it is 8, R2C2 must be 7; otherwise the pivot itself is 7. R1C2 sees all three, so remove its 7.
Step 4 of 4
Preserve the unresolved wing
Only the shared 7 is removed from R1C2; the pivot and wings still need another deduction.
Try it on today's puzzle
Unlike an XY-Wing, the target must see the pivot and both wings. Check that intersection before making an elimination.
Play today