Another option that some people might be interested in is the
CoALS Rule. The CoALS Rule states that when you have two intersecting ALS's, you can treat all of the cells of the two ALS's as one combined ALS structure. Within that structure, you then know that either all of the intersection cells digits must be represented, or all of the digits not in the intersection cells must be represented.
Sort of hard to explain, so it is good we have this example...
- Code: Select all
+-----------------------------------------------------------------------------+
| 3478 6 3478 | 5 238 1 | A478 9 *24 |
| 1 2 78 | 46 9 46 | A78 5 3 |
| 9 35 3458 | 23 238 7 | A1468 12468 1246 |
+------------------------------------------------------------------------------+
| 2356 4 2359 | 8 1236 2369 |AB16 7 B126 |
| 2367 39 2379 | 123469 12346 23469 | 5 1246 8 |
| 26 8 1 | 7 246 5 | 469 3 2469 |
+-----------------------------------------------------------------------------+
| 348 139 3489 | 13469 5 3469 | 2 1468 7 |
| 23458 1359 234589 | 123469 7 23469 | 134689 1468 14569 |
| 2345 7 6 | 12349 1234 8 | 1349 14 1459 |
+-----------------------------------------------------------------------------+
ALS A: (14678)r1234c7
ALS B: (126)r4c79
Intersection digits: 1&6
Non-intersection digits: 2&4&7&8
CoALS rule: (1&6 = 2&4&7&8)r1234c7|r4c9
Noting that the 24-cell in r1c9 sees all of the 2's and 4's in the combined ALS, we know that the Non-intersection digits cannot all be true. Therefore (1&6)r1234c7|r4c9 must be true which eliminates (6)r6c7. Add a 7 & 8 in r1c9 and the deduction still holds.
An AIC can be written as...
CoALS:(1&6 = 2&4&7&8)r1234c7|r4c9 - (2=4)r1c9 - (2&4&7&8 = 1&6)r1234c7|r4c9