## Solution/discussion of is.gd/4_days_left_2022_str8t

Str8ts discussion with Jeff Widderich and Andrew Stuart.
Stellen Sie hier Fragen an Str8ts-Erfinder Jeff Widderich und Andrew Stuart.

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Rübennase
Posts: 13
Joined: Sunday 18. December 2022, 00:12

### Solution/discussion of is.gd/4_days_left_2022_str8t

This is an interesting one!

After standard elimination, we are left with numerous undecided, interacting hi/lo's and, to me, no obvious way forward. Ben (in the 'extreme' str8ts discussion of week 652) points out 2-fish 8 25 and C-H1 must contain 8 (UR A1), also CE A9!=3. Let me throw in H8!=9 (UR). All good stuff but not decisive.

What did work for me was CE to trim down compartment ranges. After a few unsuccessful tries, I hit pay dirt at F3=7: this implies G4=2 --> 3 required in G56 but G2=3. The problem is not so much F3, but the implied F4=5, which can be eliminated. Same thing for F4=4.

After working out the consequences, my winning move was F4!=3: it would not only imply G4=2 but also a near-UR on AF35: A5!=45. This does two things: NP 36 col 5 and A4=5 (gap), the latter implying J2=5, G2=34. G4-6 must be 123, in particular G5=3 in conflict with the NP 36. F4=2, the rest wasn't difficult.

Klaus
Posts: 27
Joined: Friday 15. January 2016, 11:57

### Re: Solution/discussion of is.gd/4_days_left_2022_str8t

Hi Rübennase,

i think there are two UR-considerations:

no 2 in CH1 because of A1

and

no 3 and no 6 in B5, C5, D5 and G5 because of UR in AF35.

after that a bunch of Settis/Fishes solves without any further problems.

Rübennase
Posts: 13
Joined: Sunday 18. December 2022, 00:12

### Re: Solution/discussion of is.gd/4_days_left_2022_str8t

Wow, Klaus, this is the foil solution! Mine was the sledgehammer
To be sure: this is after eliminating 7 from F3, right? After the second UR, we can indeed trim down compartment ranges to the point of having rich fishing grounds. Really beautiful!

Klaus
Posts: 27
Joined: Friday 15. January 2016, 11:57

### Re: Solution/discussion of is.gd/4_days_left_2022_str8t

no, this after basic elimination, 7 is still present at F3

ben
Posts: 1
Joined: Wednesday 21. December 2022, 17:12

### Re: Solution/discussion of is.gd/4_days_left_2022_str8t

With a foil indeed. In fact, Klaus may have taken a deeper cut than necessary with his second UR - Just the elimination of 3/6 from G5 seems sufficient.

Uli
Posts: 1
Joined: Wednesday 21. December 2022, 20:12

### Re: Solution/discussion of is.gd/4_days_left_2022_str8t

After eliminating 7 from F3 by Rübennase the jellyfish 7 on BCDE-2345 solves.

Rübennase
Posts: 13
Joined: Sunday 18. December 2022, 00:12

### Re: Solution/discussion of is.gd/4_days_left_2022_str8t

Klaus wrote: Wednesday 21. December 2022, 16:34 no, this after basic elimination, 7 is still present at F3
You're right, of course. Just have to think one notch deeper than I did. Thanks a lot!
Same thing for the 8-in-col 1 UR: I did realize A1!=8 (UR). But that could be forced out via col 1 or row A, so I stopped thinking about it. One notch deeper: if A89=89, C-H1 must still contain 8, otherwise we're out of candidates for A1. I didn't get this far.

This is what I love these discussions for.