23
Techniques · Easy
Full House
When a row, column or box has only one empty cell left, that cell takes the one digit the unit is still missing. It is the first thing to look for and the last step of every puzzle.
How to spot it
Scan for units with eight digits filled in. Count which of 1 to 9 is absent and write it in.
Example
9
12
345
6
2
7
12458
1348
237
5
8
1
2479
279
3
249
6
4
127
6
357
2579
8
135
1259
13
2678
2678
257
47
1247
3
158
14578
9
9
3
4
8
17
5
6
17
2
1
278
257
6
2479
279
358
4578
3478
278
1278
127
9
3
6
4
178
5
678
1678
9
57
57
4
2
3
178
5
4
3
2
8
1
9
6
7
r9c9 is the last empty cell in row 9, so it must be 7 (Full House).
the pattern the cell it solves