The New Sudoku Players' Forum

[blueriley9]

Hello!
I have found myself quite stuck on this puzzle and have sought techniques, restarted it etc...but can't find the next step.
Some advice would be fantastic!

Thank you very much for your time.

Without pencil marks

. . . I 4 . 6 I 1 7 5
. 4 5 I 7 . 9 I 6 8 3
6 7 . I . 3 5 I 2 . .
------+------+-------
. . . I . . . I 5 3 7
5 . 6 I 3 4 7 I . 1 .
. . . I 9 5 . I . 6 .
------+-------+-------
. . 3 I . . . I . . 6
. . . I . 9 3 I 7 2 8
9 . . I 2 . 4 I 3 5 1


With my pencil marks

238 2389 289 I 4 28 6 I 1 7 5
12 4 5 I 7 12 9 I 6 8 3
6 7 18 I 18 3 5 I 2 49 49
----------------------+-------------------+-------------
248 1289 2489 I 168 168 128 I 5 3 7
5 28 6 I 3 4 7 I 89 1 29
2378 1238 278 I 9 5 128 I 48 6 24
-------------------------+-----------------+---------------
278 258 3 I 158 178 18 I 49 49 6
14 56 14 I 56 9 3 I 7 2 8
9 68 78 I 2 678 4 I 3 5 1

I have a photo of it as well if there's an easy way to attach/link that

[speter]

I think this is a very challenging puzzle, especially if you are solving it by hand.

There is a hidden triple (candidates 1,3,9) at r1c2, r4c2 & r6c4; which means you can remove candidates 2 & 8 @ r1c2, r4c2 & r6c4.
The move after that is a X-Wing; and then an AIC.

Good Luck.

[SpAce]

There is a hidden triple (candidates 1,3,9) at r1c2, r4c2 & r6c4; which means you can remove candidates 2 & 8 @ r1c2, r4c2 & r6c4.

A little typo: the third member of the hidden triple is r6c2 (not r6c4). Also, I'd say the corresponding naked quad (2568)r5789c2 is probably easier to find when pencil marks are used (and produces the same eliminations).

The move after that is a X-Wing; and then an AIC.

I guess you meant XYZ-Wing instead of X-Wing? Anyway, there's also a relatively simple one-step solution after the mentioned hidden triple/naked quad:

Code: Select all

.------------------.---------------.------------.
| 238   39   89-2  | 4    28   6   | 1   7   5  |
|*1(2)  4    5     | 7    12   9   | 6   8   3  |
| 6     7   *18    | 18   3    5   | 2   49  49 |
:------------------+---------------+------------:
| 48-2  19   2489  | 168  168  128 | 5   3   7  |
| 5     28   6     | 3    4    7   | 89  1   29 |
| 378-2 13  *(2)78 | 9    5    128 | 48  6   24 |
:------------------+---------------+------------:
| 278   258  3     | 158  178  18  | 49  49  6  |
| 14    56   14    | 56   9    3   | 7   2   8  |
| 9     68  *78    | 2    678  4   | 3   5   1  |
'------------------'---------------'------------'



WXYZ-Wing: (2=1)r2c1 - (1=872)r369c3 => -2 r1c3,r46c1; lclste

In other words, at least one of the 2s (r2c1 or r6c3) must be true, which makes the three other 2s (r1c3, r4c1, r6c1) that see both of them false. After that basic solving will suffice.

[blueriley9]

wow, thank you very much!