dailysudoku.com

keith · Posted: Thu Oct 11, 2007 11:00 pm Post subject: Conceptis Puzzles?

One of my other vices is collecting books. One of my recent purchases came packed in newspaper from the Springfield, IL "State Journal Register".

Included was the Sunday, Sep 30 "Conceptis Sudoku", rated *****. I have spent a few minutes on it, it is not trivial. (I do not know what it requires. It is only when I have spent a couple of hours, over a few days, that I will then use Sudoku Susser to analyze it.)

Is anyone familiar with Conceptis? I did a Google search, it looks interesting. And, interesting that I had not encountered them before now.

Keith

TKiel · Joined: 22 Feb 2006 Posts: 292 Location: Kalamazoo, MI

Come on Keith, don't leave us hangin'. Where's that puzzle?

nataraj · Posted: Mon Oct 15, 2007 4:10 pm Post subject:

did a bit of Google (Keith gave some clues) and voilà - first puzzle solved (where is the puzzle):
http://sudoku.king-online.com/client_temps/kol_current.php
select Sept 30, there you go. I didn't yet give it a try, just found the site this minute.
Today being only a "hard" day on dailysudoku.com, this comes in handy for the evening.

edit: puzzle seems kinda hard to print so here's the grid:

nataraj · Posted: Mon Oct 15, 2007 5:08 pm Post subject:

UPDATE 1704 GMT:

not trivial. you said it.

stuck right here (after I don't know what else but including xy-wing pivot r8c9, and xy-chain(s) later):

nataraj · Posted: Mon Oct 15, 2007 5:42 pm Post subject:

UPDATE 1732 GMT:

in my desperation, started medusa coloring beginning with "3" in c8:

cells r1c5 and r8c9 show "2" in opposite colors, so r1c9 must be 9.

(r1c5=4) => (r2c5 not 4) => (r2c8=4) => (r2c8 not 3) => (r9c8=3) => (r8c9 not 3)

After that, nothing worse than simple coloring.

very good puzzle, indeed.

keith · Posted: Mon Oct 15, 2007 10:25 pm Post subject:

I cannot take any credit for this! It is a very good puzzle, but it is not the one I was referring to.

I have posted the one I received with my book in a new thread, "... walk in the park".

Keith

Asellus · Posted: Mon Oct 15, 2007 11:47 pm Post subject:

I too eliminated that <2> in R1C9 using an AIC:

Either R8C9 is <2> or, alternately, <3>. If <3>, then the {56} pair in C5 means R4C5 is <9>, leading via R4C3 to a {23} pair in R4C79. However, per the alternate assumption, R4C9 must be <2>. Since either R8C9 or R4C9 is <2>, R1C9 cannot be.

After that, the {189} locked set in B7 and a Skyscraper on <1> in R27 finished it for me.

TKiel · Joined: 22 Feb 2006 Posts: 292 Location: Kalamazoo, MI

I resorted to a few XY-chains to solve this one.

Intrigued, I went to the site listed by nataraj to check out some of the other puzzles. In their archive (bad sign: It's listed as a 30 day archive and contains puzzles from Sept 19 - Oct 16. Do the math.) Of those puzzles, three are listed as 'Hard', which appears to be the top rating. One of them is Sept 30, which is the puzzle in this thread and is the only one of the three that has a unique solution. The one from Sept 23 has 7 solutions and the one from Oct 7 has 46. Kinda makes one wonder how this one ended up in there. So much for the thought of an alternative puzzle possibility, for those times of withdrawal when the VH's don't come soon enough.

nataraj · Posted: Wed Oct 17, 2007 5:50 am Post subject:

Bummer.

I was about to try the others in the "hard" category over the weekend. Good thing you checked them out first - thanks for telling us, Tracy.
Major disappointment!

As a source of high-quality sudokus I can recommend The Times. Their archive goes way back. Unfortunately, the top category "super fiendish" needs nothing more than x-wing to solve (maybe the occaional swordfish, can't remember). Very nice (esp. for P&P solvers like myself) but not really challenging.

Marty R. · Posted: Wed Oct 17, 2007 2:28 pm Post subject:

nataraj · Posted: Wed Oct 17, 2007 5:51 pm Post subject:

"high quality" in this context was supposed to mean: solvable, unique solution, consistent grading.

Difficulty level in itself is not among these criteria?

I like to do sudoku at breakfast, just after reading the morning paper. It's like brain gym, gets me awake (sort of). If there is a decent one in the paper I'll try and solve it, if not I'll take one out of a supply of printed puzzles from the internet. This happens around 5:55 am. I should get ready for work around 6:15 so that gives me between 15 and 20 minutes - perfect for those "hard" but not "very hard" puzzles.

Anything requiring a structured search like xy-wing, coloring, x-wing, swordfish or god forbid xy chains usually takes longer than that. Those are the infinitely more satisfying puzzles in the "very hard" category I do at night or on weekends. If only we could get one of these at least every other day ... (sigh).

and of course I agree "super fiendish" is a bit Wink

exaggerated

Steve R · Posted: Wed Oct 17, 2007 8:52 pm Post subject:

You may like to try Gaby Venhagen's site.

It offers six grades of puzzle each day, the “very hard” being roughly the same as here.

Steve

nataraj · Posted: Thu Oct 18, 2007 8:41 am Post subject:

Thanks, Steve, for the link - seems very promising, especially since they seem to have higher levels of difficulty, too.

nataraj · Posted: Fri Oct 19, 2007 6:46 pm Post subject:

once again, thanks Steve for pointing me in the right direction. I tried Gaby's site and liked the puzzles there. "Fiendish" grade is fine for me but I could not solve the "extreme". So, "fiendish" it is for the time being...

And then I came across Ruud's great site http://www.sudocue.net/daily.php
and already managed to solve two of these nightmare babies (Monday's and Tuesday's seem to be similar to the puzzles we find here: xwing, xy-wing coloring, maybe just a little bit more so Wink

- they are supposed to get more difficult as the week progresses)

Since there is a vast archive I think I am well prepared for those vh-less days here on this site.