All 21 entries tagged Masyu

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January 14, 2011

Friday Puzzles #87

Hmmm. Mostly unremarkable this week I’d say. Mostly. :)

#113 Masyu – rated easy

All puzzles © Tom Collyer 2009-11

December 17, 2010

Friday Puzzles #83

Busy busy busy this week, so here’s a Masyu with relatively few clues – 15. To spark a debate, has anyone seen less? I can’t recall one off the top of my head this second as I provocatively write this statement…

Anyhow, enjoy!

#109 Masyu – rated easy

All puzzles © Tom Collyer 2009-10

November 13, 2010

Friday Puzzles #78

Yes I post this entirely shamelessly, offering the fine excuse that yesterday I was rather busy having lunch and dinner in Oxford. There was a maths conference there too at some point, I think.

Anyhow, please believe me when I say that I really can’t keep this up forever. After this week I’ll give Masyu a break for a while. I can’t really compete with the Juno standard anyway. But this isn’t bad :)

#101 Masyu – rated medium

I’m also going to repost the pick of the puzzles from the recent UKPA Sudoku Championship. Many congratulations must go to our first champion Warren Harvey, a long-time reader of this blog. He topped the British contingent with a winning score of 100 points.

There was an incredible international participation too, the size of which took us aback. The top three of the table in a field of genuine world beaters were in third place Hideaki Jo of Japan, who completed the set and scored 240 points. Just a minute quicker to solve all of the puzzles was Yuhei Kusui, also of Japan with 242 points. However the clear winner was Florian Kirch of Germany, top of the pops with 256 points, completing the puzzle set with a most impressive 8 minutes to spare. Many congratulations Florian, if you’re reading, and good luck to all my other German readers who used this as a warm up to the forthcoming German championships.

As to the reasoning behind these pick of the puzzles; it’s simple. The puzzles I made I wanted to be unique amongst the background of their sub-family of Sudoku variants. With these, I succeeded and then some. I haven’t seen any puzzles anything like either of these two. Enjoy!

#102 Killer Sudoku – rated hard

#103 Arrow Sudoku – rated hard

All puzzles © Tom Collyer 2009-10

November 05, 2010

Friday Puzzles #77

Greetings all – just a quick update this week. The first two puzzles are taken directly from the instructions of the imminent UKPA Sudoku Championship. Please note that the second link takes you to a groovy new tournament page.

#098 Irregular Sudoku – rated easy

#099 Touchy Sudoku – rated medium

Please refer to the puzzle examples section of the instructions linked above to refer to the rules. I can’t really be bothered to copy and paste them here! You’ll also have the novelty of finding the solutions there too!

For my 100th published puzzle, I’ve decided to let myself go a bit. Yup, another twisted symmetry 10×10 masyu – but I reckon this one is probably harder than last week’s offering. Rest assured that I’m going to stick to my guns on this and still call it a medium – just! I am particular pleased that almost by accident I stumbled upon a way of implementing the sort of non-trivial global logic I’ve wanted to put into a puzzle of this size for a long while now. The finishing move is pretty subtle as well, but no less cool for being so. Enjoy!

#100 Masyu – rated medium

All puzzles © Tom Collyer 2009-10

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 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!

October 22, 2010

Friday Puzzles #75

A.K.A. Tom Collyer finishes unfinished business
A.K.A. Tom Collyer keeps his promises (at least sometimes, at any rate haha…)
A.K.A. Who needs a list of pentominos by the side of a puzzle anyway?

So this is a tough cookie. But it’s worth it, I promise you. 75% solves beautifully well, and the last quarter is a bit of a head scratch. If it’s too much of a head scratch, you can probably trust my good nature and use a few hinted shortcuts to finish the puzzle. Enjoy!

#092 Nurikabe – rated hard

All puzzles © Tom Collyer 2009-10

P.S. A few weeks back I eulogised about how great my Marathon puzzles for the LMI test were. As it turned out, the test was somewhat of a disaster, with a high proportion of broken puzzles and plenty of egg on my face. That said, there were still some rather good puzzles and you can probably expect to see a couple of them reposted on my blog on weeks when I’ve not got a spare mo to do a semi-decent puzzle.

Anyhow, the Heyawake was actually broken – which made me die more than a little inside because if you skipped over the contradiction the mistake implied, it was in my opinion the best of the three puzzles. I did fix it, but it’s not the same :(.

#093 Kakuro – rated hard

#094 Masyu – rated hard

#095 Heyawake – rated hard

All puzzles © Tom Collyer 2009-10

October 08, 2010

Friday Puzzles #73

I write today at silly o’ clock in the morning as something of a broken man, in terms of writing puzzles anyway. For today’s post, I would have loved nothing more than to share the three “marathon” puzzles I have written for the LMI October Puzzle test, my so-called Nikoli selection. In my judgement, they are 3 of the best puzzles I’ve done so far, and as a threesome they encompass some great design, some excellent solving manoeuvres which will be familiar to long-time readers of this blog, some more that will be novel; sometimes with a highly slick solving feel, other times with some fairly challenging logic, and yet more times where you suddenly notice something really neat that you really weren’t expecting.

However, I can’t very well go and publish them early now, can I?

Instead, I have fallen back on my trusty friend, the 10×10 Masyu, with (almost) twisted symmetry. This is one I made waiting for the rounds to finish at the Times sudoku championship last month – and I was thinking about including this for LMI until I made an even prettier design. So yeah, lazy this week. If it’s any consolation I believe there are very few people – if indeed there are any at all – who do these better than me. Enjoy!

#090 Masyu – rated easy

All puzzles © Tom Collyer 2009-10

September 02, 2010

Friday Puzzles #66

Apologies for the delay!

July 09, 2010

Friday Puzzles #60

Busy. Easy masyu. Small is beautiful. Mistake. Fix. Not quite so beautiful. Meh.

#073 Masyu – rated easy

One that works first time. Enjoy!

#074 Masyu – rated easy

All puzzles © Tom Collyer 2009-10

June 18, 2010

Friday Puzzles #57

Another week, another Masyu puzzle. As promised from last week, this features a novel new trick which you might have missed last week as it wasn’t required in the solve. So whilst I haven’t really had the time to do a juno with it this time round, you will at least have to spot it. Actually I claim it’s a novel new trick, but that’s only to the best of my knowledge.

Additionally this week, I’ve tried to give this total twisted symmetry, but it manages to break down in a couple of places. It turns out that a author by the name of cubic function has simultaneously been incorporating twisted symmetry into his puzzles – including in much larger sizes than mine for a while now too. His designs have perhaps been less striking than mine, and I’ve only picked up on it after solving a second time.

#067 Masyu – rated hard

All puzzles © Tom Collyer 2009-10

Whilst I’m on my soap-box, actually, I read this week that the “world record” for sudoku speed solving has been broken. Now the world record criteria – here denoted as STD-27 – are somewhat arbitrary, presumably to ensure a hard puzzle, but I was the first person to question this, and made a puzzle satisfying world record criteria over a year ago, solvable in the order of 2 minutes. I believe a certain Mr Snyder held that unofficial record. Anyhow, the Czechs have made an even easier puzzle than mine, and the record was broken a total of three times at this event, ultimately by Jakub Ondrousek.

At this point I’d also like to question who the three world sudoku champions featured in that article actually are, bearing in mind that there have been three in total, and only one of them was Czech!

In fairness, if there was such a thing as a meaningful sudoku world record, then you’d probably argue that Jakub O should hold it anyway; so perhaps there is no need for this particular rant…I guess it’s simply the principle of the thing. Jakub O has solved many many sudoku puzzles a lot faster than those particular puzzles!


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.

How to play:
AkariFillominoHashiHeyawakeHitoriKakuroLITSMasyuNumberlinkNurikabeRipple EffectShikakuSlitherlinkSudokuSuraromuYajilin.


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Latest comments

  • I like the appearance of the solution. :P Nice one. by Prasanna Seshadri on this entry
  • I think I've seen something vaguely similar in some of Palmer's puzzles as well. To be honest I've a… by on this entry
  • 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
  • Kota, that's not really true. I had made my puzzle before going to the WPC already. Also I don't hav… by Bram on this entry
  • About 20 minutes, after restarting from a mistaken conclusion. by Bryce Herdt on this entry

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