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Box/Line Reduction

Intermediate

Candidates in a row or column confined to a single box.

How It Works

The reverse of Pointing Pairs. When all candidates for a number in a row or column fall within a single 3x3 box, that number can be eliminated from other cells in that box.

Step by Step

  1. In a row or column, find a candidate that only appears within one 3x3 box.
  2. Since it must go in that box within the row/column, eliminate it from other cells in that box.

Practice This Technique

Try solving a puzzle and look for opportunities to apply Box/Line Reduction.

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