October 29, 2010

Friday Puzzles #76

So after the treat I served up last week, I’m afraid it’s time to come down to earth a bit this time around. This is one of those promised weeks where I’m serving up a puzzle featured in the recent LMI puzzle test I was responsible for. Albeit this one was fairly well received. I suppose that a possible ulterior motive for posting a slitherlink puzzles is that recently I have been in the habit of solving at Kwon-Tom Loop – which is curious as I don’t really enjoy the puzzles there that much. They are all taken from the generator and whilst all are certainly challenging, there is no elegance to them. On the other hand, I think that when you have a hard puzzle there should be a certain je ne sais pas to the solve that feels like getting a good bit of logic is being rewarded. Hopefully you get this here.

#096 Slitherlink – rated hard

Ah what the hell, why not have something original? I’ve been on something of a roll with my twisted symmetry masyu recently (it’s very therapeutic to design them) – and whilst it’s fair to say that most of them are fairly trivial to solve and I should really try making them in sizes larger than 10×10 – I am a bit pleased with this one as it’s by no means a trivial solve. So I don’t think that I could ever call a 10×10 masyu hard, but this at least isn’t totally easy. Enjoy!

#097 Masyu – rated medium

All puzzles © Tom Collyer 2009-10

Finally, I’d like to offer a hearty congratulations to all competitors at the 19th World Puzzle Championship in Warsaw, Poland. I wasn’t out there myself, but I have been following the progress of the British contingent via the UKPA forums with great interest. See also Thomas Snyder’s blog (over there on the left – I’m getting tired of linking everything).

Special congratulations should go to the nikoli.com solving behemoth, Hideaki Jo, of Japan, who finished third; to seven-times world champion Ulrich Voigt of Germany; and finally to the new world championship himself, Taro Arimatsu, also of Japan. You might surmise that the Japanese had an excellent time of it out in Poland, but they were ultimately pipped to the post by an excellent American team. Not only did they feature Mr. Snyder on the left there, but for the first time none other than Palmer Mebane – a.k.a. MellowMelon – whose blog you can also find there over on the left. So I suppose the final congratulations go to them.

Really finally, expect news of the immanent UKPA sudoku championship very soon!

- 5 comments by 1 or more people Not publicly viewable

  1. Deb Mohanty

    Masyu – Enjoyed how the middle part got solved. It will be very interesting to see if a 10X10 twisted symmetrical Masyu can be much more hard.

    Looking forward to UKPA Sudoku Championship.

    29 Oct 2010, 05:17

  2. Marcin Mucha

    Nice puzzles. The slitherlink is not really hard but it does have a very nice flow to it.
    For small & hard masyu check the forums of kwon tom, they have some pretty tought ones:



    29 Oct 2010, 15:55

  3. To answer the question about hard Masyu – yes I think you could have small but hard puzzles, most typically from out of the generator. I have yet to solve any of those on the kwontomloop forums, but I would not expect any of them to be particularly pleasing solves. The puzzles that I make by hand – essentially an exercise in “first I’ll start off with some initial stuff here, and then trace out the route that I’d like the solution to take” – will never have anything approaching trial-and-error steps. Which is why I think in the small space I can’t call anything hard. Firstly, there is less chance of a “d’oh” moment where you’ve simply overlooked a clue, and secondly, even if you do get very stuck, then you will only need a very shallow level of trial and error to sort yourself out.

    You should probably bear that warning in mind with regards to my rating of the slitherlink puzzle. Whilst solving the kwontomloop puzzles, I frequently resort to trial and error. But like I said in the original post, I don’t think I’ve solved one kwontomloop puzzle yet that has any sort of elegance to it. Maybe I’m missing something. I should at least concede that I do keep coming back for more – the puzzles (perhaps even including the Monday puzzles) are certainly far more difficulty than anything I’ve posted here – and I think there’s something of a sadistic streak in all puzzle solvers that likes to have a go at the big bastards. Even if it does mean coming down to solving by trial-and-error.

    Of course the art of Bifurcation is a subject I could go on about for a lot longer – but I think I’ll conclude that in general puzzles on this blog will not require any sort of “searching for a contradiction” logic that goes beyond one or two “levels of complexity”. Perhaps people may or may not have heard of the Sledgehammer “metric” in the specific context of Sudoku. The point is, that is the basis on which I am rating the difficulty of my puzzles by!

    29 Oct 2010, 18:18

  4. Marcin Mucha

    I think the masyu puzzles in the forum thread that I posted are actually handcrafted, at least some of tehm, notably ones posted by Brian. Not 100% sure though. And most of them seem to be solvable without large scale T&E that you often see in Saturday/Sunday and Beast puzzles.

    As for the kwontom slitherlinks they actually require less T&E than it seems (the regular ones at least, not talking about the big boys). Thing is, if you only do Nikoli level slitherlinks, you don’t need to figure out all the useful patters, since they are really basic. At kwontom you do. That said, I have to admit I sometimes use T&E on Monday-Friday puzzles too, but much less often than I used too when I started out with kwontom. I can’t go without uniqueness though :)


    29 Oct 2010, 20:03

  5. TheSubro

    Solid puzzles. Real nice slither and the smaller masyu had some meat on them bones.


    The Subro

    03 Nov 2010, 15:38

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Welcome to the blog of current UKPA sudoku champion, two-time Times national sudoku champion and general logic puzzle fan Tom Collyer.

Home of the original Friday Puzzles, each Friday I publish a 100% original and handmade logic puzzle, inspired by the world-famous Nikoli company.

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AkariFillominoHashiHeyawakeHitoriKakuroLITSMasyuNumberlinkNurikabeRipple EffectShikakuSlitherlinkSudokuSuraromuYajilin.


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Latest comments

  • I like the appearance of the solution. :P Nice one. by Prasanna Seshadri on this entry
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  • That's two puzzles in a row where I find something I had used before. I know, not plagiarism; just g… by Bram on this entry
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