Locked Candidates

Locked Candidates occurs when candidates in a block are restricted to a single row or column. This allows elimination of that candidate from the rest of that row or column outside the block.

Technique

1. Type 1 (Pointing): When a candidate in a block exists only in one row/column, eliminate it from that row/column outside the block.
2. Type 2 (Claiming): When a candidate in a row/column exists only within one block, eliminate it from other cells in that block.

Tips

• Scan each block looking for candidates aligned in a single row or column.
• This technique is very common and should be checked regularly.
• Locked Candidates often unlock more complex patterns.