The New Sudoku Players' Forum

[DonM]

1. grp(7)r5c78=r5c3-(7=2)r4c2-r6c2=hp(24)r6c89 => r6c8<>7
I'm not surprised you found this one to start your solution. If it seems familiar, it is: it's the same first move that you used in ASI #2c Extreme #118. Is it my imagination, or did you "target" this elimination after noting the conjugate 4's in b6 (hidden pair potential)?

Actually, I only really know about 3 moves and I recycle them constantly! But seriously it's not so much the noting the conjugate 4's as noting the entire pattern. IMO, using aHP and aHT patterns are a headset you have to get into where you see that there is an HP there...almost! This sounds obvious, but it isn't really when you start trying to actually look for them- sometimes you could swear that you have a legitimate aHP or aHT only to find that there's one more frickin' digit hiding there.

Later you were here: 8.(1=5)r5c5-r5c3=r6c2-(5)r1c2=tf(5)r36c2/r5c35-(5=6)r3c5-r3c6=(6)r4c6 => r4c6<>1=6 -> r3c5=6, r7c4=6

If the highlighted section is gone would you have the same result?

Yup, you caught me taking the long way around. For me this is a real nemesis with these ER>=8.4 type puzzles where you start to think that every move has got to be complex ie. that there aren't any 'simple' moves to be had so you end up with overkill. Also, it's one of the dangers of aXW, aJF, aTF and the like- you have to be sure that the strong link you're trying to accomplish isn't just sitting right there, available without them.

[Luke]

Actually, I only really know about 3 moves and I recycle them constantly! Very Happy But seriously it's not so much the noting the conjugate 4's as noting the entire pattern. IMO, using aHP and aHT patterns are a headset you have to get into where you see that there is an HP there...almost! This sounds obvious, but it isn't really when you start trying to actually look for them- sometimes you could swear that you have a legitimate aHP or aHT only to find that there's one more frickin' digit hiding there.

That's funny, about the three moves. I have seen the diversity demonstrated by you chain wizards and I'm always amazed in new ways (like move 3 with the group/als/group sequence.) I once called y'all "wildly creative," but now I think it's just the product of your clear and deep understanding of the underlying concepts. Anything is possible.

It seems getting the most out of chain searches does involve "targeting" and recognition of situations. There's a tall pile of chain possibilities waiting in every tough puzzle. It makes sense to work smarter not harder and look for "tells" like those conjugate pairs. My point was that I think you saw the possibilities in that particular setup based on understanding and experience, and you exploited it. Been there, done that, and since it worked, done it again.

What also seems effective is your targeting of cells with three candidates if the situation presents itself. If there's a successful elimination then a bivalue and a new strong link is created. Those newly created bivalue cells can do a lot to quickly degrade the puzzle.

As for the taking the long way around, it doesn't hurt you since it still busts the puzzle open like a pinata