The New Sudoku Players' Forum

[PeetNeef]

Hey guys,

Another puzzle again. Tried something with UR's and other techniques, but I can't work it out..

I hope the notes are clear.

https://ibb.co/fSyYmgB

[Leren]

The puzzle 4..1...5.....7..9.8.2......1....3.8..632.857..8.6....3......2.4.4..8.....9...6..7

Code: Select all

*-----------*
|4..|1..|.5.|
|...|.7.|.9.|
|8.2|...|...|
|---+---+---|
|1..|..3|.8.|
|.63|2.8|57.|
|.8.|6..|..3|
|---+---+---|
|...|...|2.4|
|.4.|.8.|...|
|.9.|..6|..7|
*-----------*

Code: Select all

*------------------------------------*
| 4  37  9  | 1  6  2    | 37  5   8 |
| 36 5  a16 | 8  7  4    | 13  9   2 |
| 8  17  2  | 59 3  59   | 17  4   6 |
|-----------+------------+-----------|
| 1  2   4  | 7  5  3    | 6   8   9 |
| 9  6   3  | 2  4  8    | 5   7   1 |
| 57 8   57 | 6  19 19   | 4   2   3 |
|-----------+------------+-----------|
| 67 13  8  | 59 19 1579 | 2   136 4 |
| 2  4   7-6| 3  8  17   | 9  d16  5 |
| 35 9  b15 | 4  2  6    | 8  c13  7 |
*------------------------------------*

This is where I think you should be. You seem to have solved r6c56 correctly as 1 & 9. Not quite sure how you did this but it doesn't affect the solution.

The cells marked a-b-c-d form what is known as a W Wing. What this shows is that one of cells a or d must be 6, so r8c3 <> 6 = 7 and the puzzle is solved. You can read up on W Wings here.

Leren

[AndyP]

My solver tries BUG+1 before W-Wings and so it sets r8c8=1 with 19 cells remaining unsolved. (It used a UR1 to eliminate 59 from r8c6 with 25 clues remaining.)