dailysudoku.com

[AZ Matt]

Okay, maybe I was too cryptic with my earlier question on this puzzle; I didn't want to spoil it for others. I'll try again (the puzzle's been up long enough):

I used the following information to solve last Friday's puzzle. I am curious if this is how others solved the puzzle (i.e., is this "the solve," or did I miss an easier route), and how an expert would describe the solve:

R4= ___ (36) ___ ___ ___ (34)
R5= ___ ___ ___ ___ ___ (37)
R6= (78}(67) ___ ___ ___ (47)

I can see that r6c1 must be 8 because if r6c1 were 7, r6c2 would also have to be 7.

Is this just an x-y wing, a variation on forcing chains, or something else?

[David Bryant]

Oh, hi, AZ Matt. Glad to see you've joined the forum!

Sorry I didn't respond a little sooner. I saw your earlier post and thought it was interesting, but I had to reconstruct the position you had reached to answer, and just didn't get around to it for a little while.

I used the same cells at a critical point in this puzzle, but didn't use quite the same logic you did. Your method is pretty slick -- you got the right number at r6c1 without doing as much work as I had to.

Here's what I had when I got to the point you've illustrated.

[AZ Matt]

Thanks David.

In the future I wll keep track of exactly where I am when I make what I think is a fairly good solve. I see from where you were at, the puzzle falls down with that solve (or is already solved another way), whereas after getting the eight, I still had some grinding to do to finish the puzzle. I suspect you get much farther along in a puzzle than I do before you get "stuck" and start looking for the "creative" solve.

I suppose someone could argue that what I did was "trial and error," since I didn't actually "see" the whole of the contradiction; what I saw was a group of pairs with an anomaluos 8, and just thought to look at it for awhile... oops, a discussion for another forum.

[alanr555]