One of my favourites
- Code: Select all
+----------------------------+--------------------------+---------------------+
| 3689* 389* 39* | 4 1 7 | 5 2 3689 |
| 135689* 2 157-39 | 356 356 59 | 689 4 36789 |
| 3569* 4 57-39 | 2356 8 259 | 69 1 3679 |
+----------------------------+--------------------------+---------------------+
| 239-15 1359 12359 | 1258 4 6 | 18 7 158 |
| 2-15 6 4 | 7 25 1258 | 3 9 158 |
| 15* 7 8 | 15 9 3 | 4 6 2 |
+----------------------------+--------------------------+---------------------+
| 248-15 158 125 | 9 7 12458 | 126 3 146 |
| 7 13589 6 | 12358 235 12458 | 129 58 149 |
| 23489-15 13589 12359 | 123568 2356 12458 | 7 58 149 |
+----------------------------+--------------------------+---------------------+
(135689)r1c123, r236c1: six digits in six cells, none can be twice, all must be there
=> -15 r4579c1, -39r23c3; ste
...or truths-links balance
6 truths, cells r1c123, r236c1
6 links, 1c1, 3b1, 5c1, 6b1, 8b1, 9b1
=> same eliminations
...or Sue de Coq (extended), or doubly linked ALS-XZ