Y-Wing

Interactive Tutorial

A Y-Wing (also called XY-Wing) uses three bi-value cells to create eliminations. The pattern involves a hinge cell that connects two pincer cells, each sharing one candidate with the hinge.

How It Works

The Pattern

Find three bi-value cells where:

The Logic

The shared candidate C in both pincers must be eliminated from cells that see both pincers:

How to Spot Y-Wings

Bi-Value Cell Focus

The key to spotting Y-Wings is focusing on bi-value cells — cells with exactly two candidates:

Step Action What to Look For
1 Find bi-value cells Cells with exactly 2 candidates
2 Pick a potential hinge A bi-value cell that sees other bi-value cells
3 Check connections Does the hinge connect to two other bi-value cells?
4 Verify candidates Hinge {A, B}, Pincer 1 {A, C}, Pincer 2 {B, C}
5 Find eliminations Any cell seeing both pincers cannot be C

Step-by-Step Scanning

  1. Scan for bi-value cells — Find all cells with exactly two candidates
  2. Pick a hinge — Choose a bi-value cell {A, B} that sees at least two other bi-value cells
  3. Match pincers — Find cells {A, C} and {B, C} that both see the hinge
  4. Identify common candidate — C appears in both pincers but NOT in the hinge
  5. Eliminate — Remove C from any cell that sees BOTH pincers

Using Candidate Highlighting

Candidate highlighting makes Y-Wings easier to spot:

  1. Look for bi-value cells in the grid
  2. When you find a promising hinge, check what bi-value cells it connects to
  3. Verify the candidate pattern matches: Hinge shares one candidate with each pincer
  4. The common candidate in both pincers is what gets eliminated

Example

Look for bi-value cells and ask: which cells can form a Y-Wing?

Pattern Analysis:

Since R9C7 sees both pincers (R8C9 and R9C3), eliminate 4 from R9C7.

puzzle: S9B0643070904054302030309054306024B5U2I0443024303070506090704030501060209080506090208030704010802012I9E7U06030509074A06054A0301020103066202BEBE052I02054A039E01BE5U06
mode: guided
technique: Y-Wing
initial:
  layers:
    hints: true
steps:
  - text: >
      Look for bi-value cells — cells with exactly two candidates.
    hint: subtle
    technique: YW
    state:
      selection:
        cells: [R9C8, R8C9, R9C3]

  - text: >
      R9C8 has {7, 8}. It sees R8C9 {4, 7} and R9C3 {4, 8}. This could be a Y-Wing!
    hint: obvious
    technique: YW
    state:
      selection:
        cells: [R9C8, R8C9, R9C3]

  - text: >
      Hinge R9C8 shares 7 with R8C9 and 8 with R9C3. Both pincers contain 4 — the common candidate!
    hint: obvious
    technique: YW
    state:
      selection:
        cells: [R9C8, R8C9, R9C3]

  - text: >
      Eliminate 4 from cells seeing both pincers. R9C7 sees R8C9 and R9C3, so R9C7~4.
    hint: detailed
    technique: YW
    state:
      selection:
        cells: [R9C7]
settings:
  showCandidates: true
  showControls: true
  showDescription: true
  navigation: numbered

The Y Shape

The name comes from the pattern's visual appearance:

       Pincer 2
          │
          │ (sees hinge via column)
          │
  Pincer 1─────Hinge
          (sees hinge via row)

The hinge is at the junction of the "Y", with the pincers at the tips.

Tips

  1. Start with the hinge — Look for bi-value cells and check what they connect to
  2. Pincers need shared candidate — The candidate being eliminated must appear in BOTH pincers
  3. Different connections — Each pincer must connect to the hinge through a different candidate
  4. Check both pincers' visibility — Eliminations occur in cells seeing BOTH pincers

Common Patterns

Row-Column Y-Wing:

Row-Box Y-Wing:

Box-Box Y-Wing:

More Puzzles

Related Techniques