SudoCue Users

I'm still trying to understand the "XZ rule" thoroughly. An almost locked set consists of N cells with exactly N+1 candidates. So I was working the "nightmare" puzzle for Monday, 2 October, 2006. Some fairly basic stuff got me to this point, where I applied a "Double Implica...

6.2.5.... .....4.3. ......... 43...8... .1....2.. ......7.. 5..27.... .......81 ...6..... This is from Gordon Royle's collection of 17-clue sudoku puzzles. When I run SudoCue (v1.5.1.3) on it, the program reports 13 instances of "table conflict" before it starts to make any real headway w...

... I shalt not guess numbers anymore. Hi again, Tomi! There's nothing "wrong" with guessing numbers. Any time you have reduced the number of possibilities in a single cell to two you can of course make a guess, with a 50% chance of being right. On a very tough puzzle, that may in fact be...

Hello again, Tomi! I looked at your picture, but couldn't really make much sense out of it. So I thought I'd take a slightly different tack. I started the puzzle from the beginning and applied all the "elementary" techniques that you described. After a bit I get to this point. *-----------...

Hello, Tomi.

Try this one, and this one. After you've whizzed through those two, you might try this one. dcb

Hi, Ron! I used to talk to Laura a lot on this forum, but she sort of disappeared about last April, or May. Maybe she'll be back when winter rolls around in Sweden again. :) I never tried to use her "colored chains" technique (in the form she describes it), because it just seems too comple...

Hi, Ron! I'm probably not careful enough with my terminology. I think of a double-implication chain as being one of two things. A. A set of two chains of inference that can be drawn by considering each of two possibilities in a "base" cell. Usually the "base" cell can only take o...

Ruud wrote:If you know what the theme for the week [09/05/06 - 09/11/06] is, tell us ...

At this point I'm still just guessing, but I'd say it's either short range Nishio or double-implication chains (aka "Empty Rectangles" and "XY Chains"). dcb

Hi, Ron! I had a lot of fun with the "ALS" week. I'm still trying to understand how to spot the useful "ALS"s in a puzzle. I was able to solve all seven of the puzzles by using "double-implication chains", which I think are in many cases the same thing as "almost l...

That's an astute observation, Ron. I'm not too good with names for some of these newer "techniques" -- I tend to rely on logic & first principles. Thanks for pointing out that this is an "XYZ-Wing" pattern. Maybe we can get Ruud to update the solving guide. Here's an example ...

Hi, all! Since Ruud is posting "pearls" on the nightmare page this week, it seems like a good time to introduce another "pearl" from my friend Andrei's collection. *-----------* |...|.1.|78.| |5..|..9|...| |...|...|.4.| |---+---+---| |.26|...|...| |...|6..|..3| |.74|.8.|...| |---...

Hi, Pepi! Here's another way to solve the puzzle from the position Ruud posted. .---------------.---------------.---------------. | 1249 12 6 | 7 1489 1249| 35 48 35 | | 49* 8 5 | 39 6 349 | 7 1 2 | | 1247 3 47 | 128 148 5 | 6 48 9 | :---------------+---------------+---------------: ...

Hi, Ruud! I really enjoyed today's puzzle, so I thought I would comment on it. I know you said that SudoCue doesn't employ double-implication chains. But I think it does use a couple of special types of DIC -- the XY-Wing in previous versions, and the "APE" in the versions you released rec...

After doing the more or less usual stuff I arrived at this position. 35 45 9 2 47+ 6 37- 1 8 34 7 18 19 5 148 39 6 2 28 126 1268 179 3 1789 4 79+ 5 6 29 27- 3 1 5 79+ 8 4 1 3 4 6 8 79+ 2 5 79- 578 59 578 4 79 2 6 3 1 9 146 3 5 2 17 8 47 67+ 47 8 17* 179+ 6 13479 5 2 379* 257 2456 2567 8 479 37 1 479...

Thanks for the explanation, Ruud. I went back through some of the earlier puzzles and managed to work a couple of those down to a BUG + 1 pattern by relying heavily on the "uniqueness" of each solution. That probably explains my problem -- like Chuck B, I usually try to avoid making that a...