Pointing
lockedPointing
LevelNot seen in a hint yet
How it works
If every cell in a box that could hold a digit lies on one line (a row or a column), then the digit must be somewhere in that box and therefore ends up on that line. So the cells of that line outside the box cannot hold it.
The candidates are locked into the overlap of box and line, and from there they point along the line to clear it. This confirms no digit — it only removes candidates. Once they are gone, singles appear that were invisible before.
Worked example
8
5
4
9
3
2
1
9
2
4
8
2
8
1
4
8
2
3
9
5
7
6
1
3
7
4
6
1
8
2
1
6
2
8
7
3
6
7
8
5
4
3
1
2
9
2
4
6
8
1
7
2
8
6
4
● evidence✕ eliminated★ confirmed
In box 9, 3 can only go in R7C7, R9C7, and those cells all lie on column 7 (marked ●).
3 must go somewhere inside box 9, so it is removed as a candidate from the other 2 cells of column 7 (✕).
Examples I encountered
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