Code: Select all
.---------------.---------------.---------------.
| 3458 39 2 | 1458 1479 5789| 6 349 3479|
| 1 45 49 | 2456 3 567 | 479 24 8 |
| 348 7 6 | 248 249 89 | 5 1 2349|
:---------------+---------------+---------------:
| 457 45 19 | 3 68 2 | 19 58 467 |
| 3457 2 34 | 9 68 1 | 47 58 467 |
| 6 19 8 | 7 5 4 | 2 39 139 |
:---------------+---------------+---------------:
| 9 36 134 | 248 247 378 | 14 246 5 |
| 24 8 5 | 1246 1249 69 | 3 7 1249|
| 234 136 7 | 1245 1249 359 | 8 2469 1249|
'---------------'---------------'---------------'
(4=5)r4c2 - (5=497)r2c237 - (7=4)r5c7 => r5c13 <> 4
Following this up, r5c3 solves as "3", r5c1 reduces to "57"; r7c3 reduces to "14" which forms a naked pair "14" with r7c7, which (among other reductions) eliminates "4" from r7c8. Then we have an XY chain (actually an XY ring):
(4=9)r2c3 - (9=3)r2c1 - (3=6)r7c2 - (6=2)r7c8 - (2=4)r2c8 => r2c2, r2c7 <> 4
Following this up, the grid becomes:
Code: Select all
.---------------.---------------.---------------.
| 348 39 2 | 1458 1479 5789| 6 349 3479|
| 1 5 49 | 246 3 67 | 79 24 8 |
| 348 7 6 | 248 249 89 | 5 1 2349|
:---------------+---------------+---------------:
|*57 4 19 | 3 *68 2 | 19 *58 *67 |
|*57 2 3 | 9 *68 1 | 47 *58 *67+4|
| 6 19 8 | 7 5 4 | 2 39 139 |
:---------------+---------------+---------------:
| 9 36 14 | 28 27 378 | 14 26 5 |
| 24 8 5 | 1246 1249 69 | 3 7 1249|
| 234 136 7 | 1245 1249 359 | 8 2469 1249|
'---------------'---------------'---------------'