ALS Chain

ALS-Chain links multiple ALS groups through restricted common candidates. When ALS groups share candidates in specific ways, powerful eliminations become possible.

Technique

1. Identify multiple ALS groups in the puzzle.
2. Find restricted common candidates (RCC) that link ALS groups.
3. An RCC appears in both ALS groups but all instances see each other.
4. Chain the logic to find eliminations.

Tips

• ALS-Chains require solid understanding of basic ALS.
• Start with ALS-XZ (simplest chain), then progress to longer chains.
• These are among the most powerful elimination techniques.