STUVWXYZ-Wing

Level 12 · Black Belt

Strategy:

Wings

Overview

STUVWXYZ-Wing is the largest wing pattern, using eight cells with eight combined candidates. This is the theoretical maximum for the wing family in a 9x9 Sudoku.

How It Works

  1. Find eight cells whose combined candidates use exactly eight digits.
  2. A pivot cell connects to seven wing cells.
  3. The one restricted candidate must be in the pattern.
  4. Eliminate it from cells seeing all relevant pattern cells.

Example

Starting position

Look for STUVWXYZ-Wing.

1

Pivot R6C3 with a 7-cell wing

Found a 8-Y-Wing pattern. The pivot cell R6C3 has candidates connected to a 7-cell wing group.

2

Wing cells form an ALS with the pivot

The wing cells R1C2, R2C2, R4C2, R5C2, R6C2, R8C2, R9C2 form an Almost Locked Set with the pivot.

3

8-Y-Wing, also called STUVWXYZ-Wing

This is a 8-Y-Wing (also known as STUVWXYZ-Wing) - the shared candidate is eliminated from common peers.

4

Remove 6 from common peers

One of the 8 cells must contain 6, so eliminate from cells seeing all pattern cells containing it: r4c3 and r5c3.

5

Result

Result after applying the technique.

Tips & Patterns

  • STUVWXYZ-Wings are the theoretical limit of the wing technique family.
  • In practice, these are vanishingly rare and primarily of academic interest.