If you look at Box 6 you will see that the three 4's in Row 4 Cols 789 are the only ones in that row, so one of them must be True in the solution. This means that you can remove the 4's in Box 6 that are not in Row 4. There should be 4 such eliminations. When you do that you should be able to see a naked pair (35) in Rows 5 and 6 Column 7, so you can remove 3 and 5 from other cells in Column 7 and Box 6. That should give you some progress. See if you can solve the puzzle from there.
Here is a diagram of the naked pair eliminations.
- Code: Select all
*-----------------------------------------------------------------------*
| 12689 1269 168 | 5 146 68 | 489-3 7 348 |
| 178 3 4 | 78 17 9 | 6 5 2 |
| 6789 679 5 | 2 467 3 | 1 49 48 |
|-----------------------+-----------------------+-----------------------|
| 5 8 136 | 9 36 67 | 24-3 1246-3 1467-3 |
| 12469 12469 136 | 14 8 567 |*35 16-3 167-35 |
| 1467 1467 1367 | 14 356 2 |*35 8 9 |
|-----------------------+-----------------------+-----------------------|
| 1678 167 2 | 3 579 4 | 89-5 169 1568 |
| 3 14 9 | 6 25 58 | 7 124 1458 |
| 4678 5 678 | 78 279 1 | 2489-3 23469 3468 |
*-----------------------------------------------------------------------*
Leren