## 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

### 3 comments by 1 or more people

1. #### Warren

For anyone who has yet to try that Killer, I must say that, from a Killer lover, that is quite possibly one of the nicest puzzles I’ve ever had the privilege to solve. A true work of art!

Thanks for all your work for the competition, Tom.

15 Nov 2010, 10:34

2. #### Thomas Snyder

Got through the UK test this weekend. I must agree that the Killer is a real thing of beauty with much that felt new in the discovery process. Certainly the true stand-out of the test. The arrow looks cool but solved really well by just trying to force numbers into the connections, and therefore a little more twiddly than desired. Admittedly, I had an intuition for how that would go, but I got it out in about 1/3 of the Killer time, for the same point value.

15 Nov 2010, 18:58

3. Thomas – the Arrow was a high variance puzzle – you either got the idea straight away, or you didn’t. Our testers didn’t – and they are no mugs – so we thought it safest to award a high number of points for it, rather than to perhaps take a latter day USPC line with it. A natural side effect of this was it acted as a natural warning of “don’t be surprised if you struggle with this one!”

I am glad the killer went down well. I don’t do very many killers, because you only need a few mundane techniques here and there and you get something that solves fairly easily and without any interest at all. To do something a little bit different does require a bit of head-scratching and there are only so many hours in the day. Maybe people will find it interesting to know that before I got the puzzle nailed down I had a hell of a time trying to get the last few permutations of numbers to yield the unique solution. This is why the cages are no longer entirely symmetric (but still good enough to have a fairly eye-catching design).

16 Nov 2010, 20:30

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## Information

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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