Medium Used from medium puzzles up.
Locked Candidates: Pointing
A box's candidates in one line
Within a box, the candidates for a digit sometimes all lie in the same row or the same column.
Wherever the digit ends up in that box, it is in that line. So it cannot go anywhere else on the line: remove it from the line's cells outside the box.
The box points along the line, and clears the digit beyond it.
What to look for
Find a box where the candidates for one digit all sit in one row or one column.
Example
- The cells the technique relies on
- Cells where it removes candidates, struck out in red
Practise it
In the app, Learn › Locked Candidates: Pointing sets exercises on real positions, then a full puzzle that needs this technique and nothing harder.