The Locked Triple Technique in Sudoku

Locked Triple

A Locked Triple occurs when three cells forming a Naked Triple (three candidates restricted to three cells) span two overlapping houses.

Eliminations apply to both houses.

Example 1

Cells R7C5, R8C5, and R9C5 form a Locked Triple in Column 5 (C5) and Block 8 (B8). This removes candidate 9 from R8C4 (in the block) and R2C5 (in

the column).

Example 2

A Locked Triple in Row 5 (R5) and Block 6 (B6) eliminates 18 candidates, targeting values 5, 6, and 7 across both houses.

You've just seen how triples work — explore Locked Pair and the general Locked Candidates Technique to see the logic applied with different candidate counts.