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Lesson 03 · Sudoku Coach

Locked Candidates Sudoku lesson

Candidates confined to one line inside a box eliminate that digit farther along the line.

The working method

  1. 1.Find a digit whose candidates in one box all share a row or column.
  2. 2.Treat that shared line as locked by the box.
  3. 3.Remove the digit from other cells on the same line outside the box.

Evidence exercise 1 of 3

Find the proof, not the answer.

Select all 2 evidence cells that make this Locked Candidates deduction valid.

What to inspect

Candidates confined to one line inside a box eliminate that digit farther along the line.

Source puzzle · sudoku-0003

Candidate marks reflect a verified intermediate state from this published grid.

Open the full puzzle

Use mouse, touch, or keyboard. Arrow keys move focus; Enter or Space selects a cell.

Notes mode off