Puzzle Description:

Who’s afraid of this little mouse?

#1: Wombat (wombatilim) on Feb 15, 2018 [HINT]

R58: You can do some extended EL with the 12 to eliminate C1-19 and C36-40. LL.

C38: EL with the 7 will let you eliminate R1-12. LL.

C39: EL with the 14 places it in R23-36. LL.

C40: EL eliminates R40, 47, and 56-57. LL.

C31: Starting the 21 above R8 causes a contradiction in C32, so R1-7 C31 are white. LL.

C32: Starting the 15 above R8 causes a contradiction in C33, so R1-7 C32 are also white. LL.

C33: Same as C31 and C32. LL.

C29: You can use IEL to eliminate R1 and R7. This places black in R4. Since R4 is the only row in R2-6 that has a possible 1 clue in that column, and you're looking at a pair of 2-clues in C28, that black in R4 C29 must be the 1-clue in R4 to avoid a contradiction in C28, so you can mark R4 C28 as white. LL.

C36: IEL on the 2nd 6-clue to eliminate R22-25. LL.

I think this is about as much of this puzzle my brain can handle for the day. Not giving up hope yet.

It's very cute indeed, but should be made solvable!

@Wombat: I got a lot farther than you, but didn't keep track of notes. I got down to placing the 6 in R59 and faced two options. Borderline deep lookahead/guessing. The puzzle did not become more solvable afterwards. In fact, it went the other way. There may be an argument for deep lookahead over a dozen times. But at some point, that's guessing in my book.

@ Dik - Deep lookahead is never guessing. No matter how many times it's done. Each bit of deep lookahead produces a logical conclusion. If you cannot get a logical conclusion then it's NOT deep lookahead, it's guessing.

I agree. I like a challenging puzzle myself and this is what I try to acheive. However, it may take trail and error to solve, such as row 49. I hope you find it worthwhile, even though it does require some work to solve.

I am not so advanced that I never needed to guess; I have not even attempted to master deep lookahead yet. However, there were some parts that required a keen eye to find easy-to-miss line logic. More than anything, I loved that about this one. I love advanced line logic. It is a thrill to me whenever I find those nuggets that require deductive logic - that is, logic that doesn't place any black, just tells you where black absolutely cannot go.

And the little critter is a cutie. Nice art.

@Joe I mean at what point is deep look-ahead guessing? After several instances guess-and-check and then working backward to see if I could have logically arrived at the conclusion, I gave up. Not worth it.

I relied a bit on picture logic, which is no bueno, for a logical purist.

Still, s/he's awfully cute.

A belated answer to Dik:

Deep Lookahead is never guessing.

Line logic is: since x then y (within one row or column)

Moderate lookahead is either:
> since x then y (using crossing rows or columns)
> if x then y [and z] Using an assumption that comes to a DEFINITE conclusion within a couple steps.

Deep lookahead is then: if x then y and so z and then aa follows, [and ab] Using an assumption that reaches a DEFINITE conclusion in more than a couple steps.

On this website, we define logical as being able to keep the logical steps within one's head. (Or, in another idiom, being able to do the puzzle in ink with no erasures or temporary marks.)

Thus deep lookahead is a fuzzy category. Some deep lookahead is easy like zigzags which can go many steps with perfect clarity. Other deep lookahead can get really hairy in just a couple steps. However, the thing to remember is that all "lookahead" ends in a *DEFINITE* conclusion. If you are not 100% sure what you've marked is correct, then you've guessed.

For a puzzle to be given a deep lookahead classification, somebody needs to have given a well-documented method of solving.

Joe, thanks for clarifying. I didn't really fully understand deep lookahead either, but I knew that in some way it wasn't guessing. The line that really spells it out to me was this: "all 'lookahead' ends in a *DEFINITE* conclusion. If you are not 100% sure what you've marked is correct, then you've guessed."

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