Remote Pairs

Remote Pairs uses a chain of bi-value cells all containing the same two candidates. Cells at opposite ends of an even-length chain have opposite values, allowing eliminations.

Technique

1. Find a chain of bi-value cells all containing the same two candidates {X,Y}.
2. Each cell in the chain must see the next cell.
3. Cells at ends of an even-length chain have opposite values (one is X, other is Y).
4. Eliminate both X and Y from cells that see both endpoints.

Tips

• The chain must have an even number of cells (4, 6, 8, etc.) for eliminations.
• Cells alternate: if first is X, second is Y, third is X, etc.
• Any cell seeing both endpoints can't be either candidate.