145
Techniques · Medium
Pointing
If, inside one box, all the places for a digit lie on a single row or column, the digit in that box will end up on that line. So the digit cannot appear anywhere else on that line outside the box.
How to spot it
In each box, check where a digit can go. When its candidates line up on two or three cells in a row or a column, remove that digit from the rest of the line.
Example
3
15
4589
489
158
2
6
7
2
145
7
345
6
135
13
8
9
9
6
8
237
237
1237
5
4
13
8
125
9
257
27
4
167
3
156
6
25
235
1
237
9
4
257
8
4
7
1235
6
238
2358
9
25
15
5
3
4
79
1
6
8
79
2
7
9
26
238
5
238
36
1
4
1
8
26
23479
23479
237
367
579
356
In box 7, 2 is confined to column 3, so 2 can be removed from the rest of column 3 (Pointing).
the pattern cells that lose a candidate (crossed out)