145
Techniques · Easy
Naked Single
When a cell's row, column and box already contain eight different digits between them, only one digit can go in the cell.
How to spot it
Look at cells in crowded rows and columns. With notes on, it is any cell with exactly one note left.
Example
3
15
4589
1489
158
2
6
7
2
145
7
345
6
135
13
8
9
9
6
8
237
1237
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
125
15
5
3
4
79
179
6
8
179
2
7
9
26
238
5
1238
136
1
4
1
8
26
23479
23479
237
367
579
356
r8c8 has only one candidate left: 1 (Naked Single).
the pattern the cell it solves