dailysudoku.com

[Mogulmeister]

I thought on the return of this board that I'd like to share this puzzle I've been chewing over. It is the current Extreme #32 and is from the Mepham site so it's one of Andrew Stuart's. You won't be able to run his solver on it until Sunday !

Here it is in its original form:

[Mogulmeister]

I arrived at this point and noticed what (I think??) is a "finned squirmbag"
however, better minds than mine can probably advise.......

This is on 2's. The squirmbag is in green, the "fin" is salmon pink and the eliminated 2's in blue. The puzzle solves easily thereafter.



I'd be interested in:

a)Comments - is this so ?
b)What other solving paths would you follow ?

Thanks. Mogul

[Ruud]

You have correctly identified a finned squirmbag, but it does not yield any eliminations.

EITHER the candidate 2 in R2C1 is true OR the squirmbag for digit 2 in columns 12578 is true. You would only be allowed to eliminate digit 2 from R3C12 if they were present.

Alternative steps:

Finned X-Wing for digit 4 in rows 25, columns 49 with fin in R2C6, eliminates digit 4 in R1C4.

Finned Swordfish for digit 2 in rows 258, columns 149 with fin in R8C7, eliminates digit 2 in R9C9.

ALS-XY rule: A=R1C2 {2,4}, B= R2C1346 {23467}, X (restricted common) = 2 (in box 1), Z=4. Digit 4 can be eliminated from R1C56.

After that, the puzzle still requires several advanced steps like Nishio (digit 2), 3D coloring, Swordfish, XY-Chain.

Ruud

[Mogulmeister]

Sorry Ruud you refer to R3C12 but that is just a 9 and 48 - I don't see any 2 present. Please enlighten - I'm being a bit slow today.

[Ruud]

[Mogulmeister]

Thanks Ruud. So in effect the blue eliminations only apply when the Squirmbag is true and the fin is false. I certainly wouldn't want to truth table that lot.

[Mogulmeister]

Interestingly, the squirmbag is true in this case which is why the eliminations worked.