The puzzle in line format : .3..............181.6...7...7...49...2.6....5..128....9..........7.1864.....95...

Here is where you should be after basic moves (note r7c2 is 18, not 1 as in your diagram - in fact in the solution it is 8. Also you missed a BoxRow intersection 3 in r6c789 that removes 3's from other cells in Box 6 and solves r5c8 = 8):

- Code: Select all
`*---------------------------------------------------*`

| 478 3 *25 | 1589 2457 127 |*25+4 2569 246 |

| 47 49 *25 | 59 234567 2367 |*25+34 1 8 |

| 1 489 6 | 589 2345 23 | 7 2359 234 |

|--------------+------------------+-----------------|

| 368 7 38 | 15 35 4 | 9 26 126 |

| 34 2 9 | 6 37 137 | 1-4 8 5 |

| 5 46 1 | 2 8 9 |#34 367 3467 |

|--------------+------------------+-----------------|

| 9 18 348 | 47 26 26 | 158-3 357 137 |

| 2 5 7 | 3 1 8 | 6 4 9 |

| 368 168 348 | 47 9 5 | 128-3 237 1237 |

*---------------------------------------------------*

There is a Type 3 UR (25) in r12c37 with extra digits 34 in the Roof cells. The 34 bi-value helper cell r6c7 creates an effective naked pair 34 in r126c7 so you can remove 3 and 4 from other cells in Column 7, which solves the puzzle.