## Chains Abound ... But is there an Alternative

Post the puzzle or solving technique that's causing you trouble and someone will help

### Chains Abound ... But is there an Alternative

P_Set_C: #3

Code: Select all
` 5.1....78.6.....297.....1.........8.....9.2.6.....49.1..8.67...69.2.....21..89..7 next? +-----------------------------------------------------------------------+ |  5      234    1      |  9      23     236    |  346    7      8      | |  348    6      34     |  34578  1357   1358   |  345    2      9      | |  7      2348   9      |  34568  2345   23568  |  1      3456   35     | |-----------------------+-----------------------+-----------------------| |  9      345    26     |  356    1235   12356  |  7      8      345    | |  1      34578  345    |  3578   9      358    |  2      345    6      | |  38     3578   26     |  35678  2357   4      |  9      35     1      | |-----------------------+-----------------------+-----------------------| |  34     345    8      |  1      6      7      |  35     9      2      | |  6      9      7      |  2      345    35     |  8      1      345    | |  2      1      35     |  345    8      9      |  3456   3456   7      | +-----------------------------------------------------------------------+ # 98 eliminations remain`
daj95376
2014 Supporter

Posts: 2624
Joined: 15 May 2006

Are you considering application of ALS xz and ALS xy-wing rules as non-chains?
ronk
2012 Supporter

Posts: 4764
Joined: 02 November 2005
Location: Southeastern USA

ronk wrote:Are you considering application of ALS xz and ALS xy-wing rules as non-chains?

Normally, I would say no because I'm often (but not always) able to duplicate ALS eliminations with a chain. However, in this case, I'll accept any approach that keeps me from generating several consecutive chains before the puzzle opens up. I'll even accept chains if someone can show how to reduce the number needed without having to perform combinatorics on all possibilities.
daj95376
2014 Supporter

Posts: 2624
Joined: 15 May 2006

Hi Danny,

daj95376 wrote:However, in this case, I'll accept any approach that keeps me from generating several consecutive chains before the puzzle opens up.

I don’t know exactly what you meant and I came to :
[r5c3]-3-[r6c1]=8=[r2c1]=8=ALS:([r2c456]=178|5=[r2c456])=5-[r2c7]-5=[r7c7]=5=[r7c2]=5=[r9c3]-3-[r5c3] => r5c3<>3

I’m not sure for presenting grp(178)r2c456 as ALS on NL notation, please correct me. From here I was found many chains to the end…

Thanks
ttt
ttt

Posts: 185
Joined: 20 October 2006
Location: vietnam

daj95376 wrote:...I'll even accept chains if someone can show how to reduce the number needed without having to perform combinatorics on all possibilities.

Best I can do is 3 nets and one chain before SSTS will crack it. Happy to post the steps if you're interested, but I suspect that is more steps than you'd like.

Cheers...

- drac
Draco

Posts: 143
Joined: 14 March 2008

Draco wrote:
daj95376 wrote:...I'll even accept chains if someone can show how to reduce the number needed without having to perform combinatorics on all possibilities.

Best I can do is 3 nets and one chain before SSTS will crack it. Happy to post the steps if you're interested, but I suspect that is more steps than you'd like.

I appreciate your effort, but already have a solution using: 2x chains, a SIN, and several non-chain techniques.

There were six original chains reported by my solver. Of those, two were necessary. They reduced the puzzle to where one SIN opened the puzzle to where lesser techniques completed it.

I was hoping that someone had a way of selecting the necessary chains from the also there chains. Failing that, I was wondering if anyone had an alternate solution that wasn't too involved.

Thanks again for working on this puzzle/problem.
daj95376
2014 Supporter

Posts: 2624
Joined: 15 May 2006