Box symmetry: r123456789 -> r456789123, c123456789 -> c456789123, 123456789 -> 231564789
- Code: Select all
.-------------------.-------------------.-------------------.
| 4 5 #123 | 2379 2379 #23 | 8 1369 1236 |
| 6 #12 7 |#239 45 8 | 1239 1359 12345 |
|#23 8 9 | 6 #1 45 | 237 357 2345 |
:-------------------+-------------------+-------------------:
| 8 1249 1234 | 5 6 #123 | 1379 1379 #13 |
| 1239 1269 12356 | 4 #23 7 |#139 56 8 |
| 137 167 1356 |#13 8 9 | 4 #2 56 |
:-------------------+-------------------+-------------------:
| 1279 1279 #12 | 8 2359 1235 | 6 4 #123 |
|#129 46 8 | 1239 2349 12346 | 5 #13 7 |
| 5 #3 46 | 127 247 1246 |#12 8 9 |
'-------------------'-------------------'-------------------'
DP 123#, internals 9r2c4 9r5c7 9r8c1
At least one of the internals must be true and so must be its symmetric images by uniqueness, therefore all of them are true. stte
eleven wrote:without the givens 5 and 6 in boxes 7 and 2 this grid has 2 solutions
I don't understand what you mean.
What can you say about the resulting puzzle, when you have deleted the 56 but not the 4?
By deleting the 4 as well, you get seven solutions with 2b159p3 as well as the expected seven solutions with 1b159p3 and seven solutions with 3b159p3.
Marek