All entries for May 2010

May 29, 2010

How Many More Times

A.K.A.

WSC5: Philadelphia write-up

Lots of runners up for the title of this post, including “Ramble On”, “I Can’t Quit You Baby”, “The Song Remains The Same”, (more optimistically) “Your Time Is Gonna Come” and (most tenuously) “Hats Off To (Jan Mrozowski)”.

I’m going to aim to post with slightly more brevity than my report last year, what with the suggestion from a certain Mr McNeill that I have a tendency to go “off on one” with my blog posts. But only slightly!

The beginning of this particular story should start with the fact that this trip marked the first time I’d ever been to America. Or indeed the first I’d left Europe and its convenient immigration conventions. Our flight was round about midday on the Thursday, which was nice and comfortable in terms of timings to get to the airport. This was simply a case of catching a fats train down to London, and transferring to the Heathrow Express and getting there in less than two hours. At the airport, I first spotted George D – another member of the UK team – and then his parents who were coming along for support and a holiday afterwards. We checked in, had a coffee and set off.

Ah – I said set off – where in fact I meant got onto a plane, where the luggage van promptly crashed into the plane and caused about a two hour delay whilst pictures were taken and sent to America for inspection, fixes were made, and bonds were setting. Incidentally, two hours is about how long it takes for me to fully exhaust a copy of the Times, together with all the puzzles (except the cryptic crossword).

Seven hours is a long time to be on a plane, especially with a poor selection of in flight entertainment, and the quirky novelty of the food – including fruit juice from a can. In this long long time I managed to get about 10 clues out of the cryptic. Meh.

We got into Philadelphia at round about 5 or 6, where it was beautifully sunny and warm. A shuttle bus had been arrange, which we shared with a troupe of dental surgeons from North Carolina, who were most intrigued with the idea of competitive sudoku. The hotel we were staying at – the Courtyard Marriott – was literally in the centre of town. Let me qualify this statement: Philadelphia was built by William Penn, with a lovely grid system and with five open squares to mark a sort of boundary. Four are on the corners of an imaginary square you can draw over the city; the fifth is at its centre, and on it is located the city hall. It might interest you to know that on top of the city hall is a statue of Mr Penn, and the statue is the highest one anywhere in the world on top of a building. Anyhow, also on this square is the hotel. Brilliant.

The usual faffing around in the hotel, together with the wait to get a quaint old trolley bus meant that we were slightly late getting to the reception in the Philadelphia Visitors’ Center. On the plus side our team minder, a woman named Sue, was giving us a pleasant introduction to Philly. By the time we arrived, the food had mostly gone which seemed a shame at the time, but I have been reliably informed that it was pretty poor fare anyway. Still, a couple of free glasses of wine, some acquaintances with old friends and the official team introductions was a good way to pass the evening. We had a bit of a team discussion with the rest of the UK contingent – Mike C and David M – before I slunk off to my room to get some sleep.

Friday morning brought more sunshine and a hotel breakfast. This being my third world championships, I have to say this was probably the least favourite – far more satisfying and hearty fare in Prague and Zilina, not to mention less greasy. I ended up topping up with some rather sugary cereal. Lots of American food seems to me excessively sugary. Anyhow, whilst some other teams spent the morning off, team UK headed up to the room David M and Mike C were sharing and had a discussion of the sudoku variants that were to come up later in the day. Just before lunch, we headed over to the Love park for an official team photo, bumping into a few other teams – including the Canadians in the process.

Lunch was a new innovation – instead of something at the hotel place – which was much too small to house the whole WSC conga line, we were given vouchers to spend at the vast indoor Reading terminal market. Food here was fresher and nicer than the hotel, and brings me to my second observation of American food: the vast portion sizes. I had to negotiate a tricky problem of geometry in trying to fit my sandwich into my mouth, but was pleased there was another half of it to have as snack later.

So – back to the hotel and onto competition. The championship this year was rather cheesily themed as a decathlon, with events from the latter vaguely paired up with rounds of the championship.

Round 1 (100m)
20 minutes, 8 “easy” classic sudoku puzzles to do. These weren’t as easy as might have been expected, all at least Times difficult/fiendish level puzzles. I’d have had 6 of the 8 done in time, but made the dickhead error of not filling in the last three numbers on one puzzle. Jakub “jaku111” Ondrousek got all eight out, an impressive feat, but not a bad start for me; 16th in the round with 62 points out of 100.

Round 2 (Long Jump)

40 minutes. I only got out 3 puzzles out – the killer, arrow and color sum puzzles. The arrow puzzle in particular was a thing of great beauty, and one of my favourite puzzles of the entire championship. I made a dickhead error on the integer division, losing 14 points, and I really ought to have got the little killer out but was probably undone by time pressure. 38th with 66/200. Props to my man Jason Z who top scored on this round!

Round 3 (Shot Put)

40 minutes. A pretty decent round for me, I got all but three puzzles out – unfortunately two of these were parquet and double cairo – together worth 77 points. I perhaps spent too much time in this round on puzzle not worth huge amounts of points. 26th with 108/190. Salih Alan of Turkey, and Jan Novotny of the Czech Republic finished the round.

Round 4 (High Jump)

35 minutes. Again under par, with only three puzzles completed: consecutive, thermometer and outside. Part of this was down to messing up the consecutive puzzle; on the other hand I should really have spent time on the fortress which was worth 33 points and was very gettable. On the other “other hand” I was at least somewhat pleased that the thermometer appeared to need an x-wing to solve, after taking lots of stick from Mike, George and David for my fondness of the technique. 47th with 71/155.

Round 5 (400m)
35 minutes, 8 “medium” classic sudoku puzzles to do. These were of the level of old Times fiendish (Pappocom hard) or the current super-fiendish lot. In winning the UK title last September I solved 4 of these puzzles in just under 17 minutes, so I was aiming to finish this round. I was on course to do so, but cocked up a puzzle and had to restart – leaving me to finish just 6 puzzles. Once again Jakub O finished, along with Jan Mrozowski. 109/155 and 17th place for the round for me.

Competition wasn’t quite over for the day as next up were two team rounds. At this point the jet lag was beginning to kick in a bit – although the mental strain of world championship sudoku probably had something to do with it too. Still, what with us having the best UK team out there, me David and George felt we could give this a good shot.

Weakest Link
40 minutes. The first of a truly superb set of team rounds executed brilliantly. The idea here is that as individuals, the team had to solve the same double-triple puzzle (two sudoku grids each sharing unmarked three 3×3 boxes); as each team member finished their individual puzzle, pieces of the next puzzle were handed out. This was a triple-quadruple puzzle: four classic puzzles, with each grid sharing a 3×3 box with one other. Obviously you couldn’t solve the entire puzzle unless all three team members got the first hurdle. David was quickest here, with me about 30 seconds behind him. With only three of the four pieces to play with, progress was slow – although coherent. Our theory was that even if George had been quicker finishing the individual leg, the confusion in communicating between the four puzzle pieces with three rather than two people wouldn’t have led the puzzles to being solved much quicker. Still, we finished before time, securing 1200/950 points – but only 8th best.

Number Place

40 minutes. Another brilliant idea. Six classic puzzles to do, with three being solved at any one time. The twist came was that each puzzle had three coloured areas, each participant had sets of coloured stickers that they could only stick in their own coloured area. 90 seconds. This could have gone better for us – we made mistakes and had issues with wonky stickers (well George was the main culprit here) – but we were able to fix them for the large part. 884/1000 and 9th for the round.

With puzzling over for the day, it was time for some food. Dinner was at the hotel, a sort of buffet affair. I was a bit late to get there, but managed to get a couple of bits of steak. Overly done and too seasoned was my verdict, but the meal was certainly vindicated by the desserts, of which I had four. The fifth item was a chocolate eclair, which really was far too much. With everything washed down with a couple of canned drinks – containing my entire recommended daily intake of sugar – I was also negating the time-zone difference.

After the dinner was a games night. The first game was introduced by Nikoli president Maki Kaji, a long time fan of horse racing (Nikoli indeed being the winning racehorse of the 1980 Irish 2,000 Guineas race). The idea behind the Nikoli derby is that everybody picks a number, and the lowest number which has been chosen once wins. An interesting psychological game, and one I’m sure with interesting evolutionary game theoretic strategies. In the last online version, my horse placed 5th, so I was fairly confident about where to pitch. In the first round, as I thought, everyone was very cautious and a low number won – #2 (which was incidentally the tip Maki Kaji gave me when I asked him as he came round to collect the numbers); but my horse “Retuned Daddio” in gate #5 came home in 2nd place. This earned me a handshake with the Great Mr Kaji, as well as a Nikoli bandana thing, which I took great pleasure in wearing for pretty much the rest of the championship.

The second round saw the room lose their inhibitions, and as a result it was only #18 that actually came home. In 2nd place with #20 was none other than David M – who also got a bandana. The next game involved a volunteer from the audience to pick four random cards with things on, which the volunteer ranked in order. The rest of the audience then had to guess how the volunteer had ranked the things. Most memorable was the Canadian Byron Calver, who drew “Barack Obama, Vodka, Tattoos and Ironing”, and began the explanation of his ranking by remarking

I’ve never done three of the four things here,

continuing:

although maybe four things depending on your definition of “do”.

Absolute priceless. A close second was Psyho – an excellent nikoli.com solver who I’d never have placed beforehand as a Pole – and his face when someone in the audience reasoned that he was a man and thus “chocolate” couldn’t possibly be his favourite thing.

After the games, we had another UK team meeting in David/Mike’s room in which I was beginning to flag rather badly and so didn’t really take in much. Of course the solution to this – as readers from last year will be doubtlessly be screaming out at their screens – was to go to the hotel bar. I did, and met my old drinking buddy Jason “Ziti” Zuffranieri for a beer. I pipped for a Victory Hopdevil, an IPA style beer with plenty of hoppy bite – definitely an excellent real ale although arguably chilled a little too much. After a little while, we caught Maki Kaji and Tetsuya Nishio (the Japanese team captain) as they were leaving after a couple of large whiskies, and we tried to relay just how awesome we thought nikoli was. They seemed honoured, and as a bonus told me lots of other uses for my bandana. Such as a mouse mat, or a pencil case! Jason and I finished up soon afterwards, and retired.

The time-zone difference meant that despite a fairly late night I had no trouble getting up early in the morning, which was a good thing seeing as competition was to start at 9am.

Round 6 (110m hurdles)
This round was an innovation – the idea being to take a “sudoku”-like puzzle (i.e. a grid as you know and love, but one that could filled out with multiple solutions), and make exactly one deduction. 20 such puzzles to get through in 20 minutes. Sounds easy right? Well, no-one finished, and indeed I only managed 13. 70/110 and 6th best. Not bad, considering there were a couple of self-kicking moments.

Round 7 (Discus)

35 minutes. I thought I had all but two puzzles out in this round – the hexagon and the musketry – but made a dickhead error on the double irregular which cost me 12 points. I thought I’d done pretty well with this round, knowing I’d probably not have time for the hexagon and the musketry, but it seems the rest of the field had a good round too – including once more Jan Novotny of the Czech Republic who once again finished the round. 51st with 84/155.

Round 8 (Pole Vault)

40 minutes. A pretty nightmarish round for me. I repeatedly cocked up the 6×6 digital sudoku, wasting plenty of time. It was also galling to find out I’d cocked up the S as in sudoku puzzle too after spending a fair old amount of time. This lost me a potential 45 points for the round. I did manage the dice pip, the morse and the roman numeral. I should also mention that the inverse digital letter sudoku was a thing of absolute genius – clued with perfect reflective symmetry in the horizontal axis. it was a pretty nice puzzle, and given its weighting at 55 points was probably worth attempting. 67th with 59/200.

Round 9 (Javelin)

The nightmare was fully on this round as a large portion of time was spent on the absolutely solid irregular puzzle – arguably one of the hardest irregulars I’ve ever done. I must have wasted a good 20 minutes on this 40 point puzzle before it totally KOed me, and so I only got out the sudo-kurve (a lovely puzzle) and the weave. The ten-box was rock solid and probably not worth attempting, but the the penrose-2 was definitely gettable, as was the primrose – especially in the time wasted with the irregular. 95 points that could have been. :( A disastrous 73rd with 22/225.

Round 10 (1500m)

35 minutes. This was the so-called “guessing” round – classic sudoku puzzles requiring more complex and hard-to-spot constructive logical steps to solve, meaning that the best bet was to make well chosen guesses. I thought I’d managed to get a fairly average total of 4 out of the 9 puzzles out, but it turned out that what had felt like a solve was actually a mistake, and 40 points were frittered away, leaving me with a below par 3 puzzles for the round. 42nd with 89/310. Although it must be said that afterwards I had a chance to chat with constructors Thomas Snyder and Wei-Hwa Huang, who pointed out that they felt there was absolutely no chance that anyone would finish – the last puzzles in the round being picked out so that picking a point at which to guess would be far from trivial. I must add however, that after the competition was over I got the last puzzle (anonymously contributed from some enthusiast hard-puzzle forum) in a mere 4 minutes.

So individual competition over, and I suspected that I had performed a little under par. My overall stats were 38th with 740 points, ranked 21st for the classics only portion (a result which was only as low as this thanks to the lottery of the guessing round), and 49th for the variants only – which is probably fair enough after a few disastrous rounds. An extra 150-200 points would have pushed me up towards the 10th-20th places I was aiming for.

Still, there was all to play for in the the remaining team rounds. We went for lunch again in the Reading Terminal market, and headed back for more sudoku!

Jigsaw

30 minutes. I’m sure I’m missing something, but constructing something like this seemed like a feet of incredible genius. The idea was you were given a set of cardboard jigsaw pieces, with printed clues in 8 orientations, which then fitted together to make four irregular puzzles. There were four different shapes of clues to fit together. Brilliant. It took us quite a while to crank out the patterns, let alone fit the puzzle pieces into the right place, but eventually we got going on solving a couple of them. As it was, we only solved one of the four completely, but given another 5 minutes and I think this would have been three. Still, not a bad effort 350/800 points and 8th place.

Track and Field Relay

40 minutes. Ahhh – what is and what could have been. Six rounds of puzzles, with at any one time two people working on a variant, and the other working on a standard sudoku. Points were only awarded for a leg if both puzzles were solved correctly – the idea being that the classic was going to be much easier than the variant. First up was integer division sudoku, me and George. We thought we got this out pretty well, but it turned out we managed to make a dickhead error towards the end of the solve. Next was countdown sudoku – I didn’t see this as this was my turn to be whizzing through the classic, but David and George got this out with no problems. Third up was a 9×9 skyscrapers puzzle, with me and David working on this. I must admit I very much played second fiddle here – David with WPC experience would have been fine by himself here; my contribution was to simply speed up his deductive process. He’d lspot where to look in the grid, and I made negative deductions to complement his own thinking. Overall, a very nice team solve.

Half-way through this round, and back to me and George solving. This was a double irregular puzzle; one pattern a standard sudoku grid, the other remarkably similar to the pattern I used for a killer. I think this was my best solve of the entire championships – we finished the supposedly harder variant a minute before David had the classic out. At this stage I think we were aware we were well in front of the entire room. Fifth puzzle was a morse sudoku, although again I was doing the classic puzzle and didn’t see this. Still, this was hammered out with no problems at all. Finally, sudoku weave. This is normally a puzzle that I find massively counter-intuitive; however the dual solve with me and David was again a thing of absolute beauty – basically whilst he was looking down one particular weave, I cross-checked the transverse weaves, and we thought we were done with the round, with a massive time bonus. Except the dickhead error cost us. 800/960, 5th for the round, but with the extra 160 points + bonus and it could have been a real winner for us.

Pentathlon

40 minutes. Still on a high from what we thought was an awesome round, we had this round similarly nailed. The idea was four different sudoku variant – deficit, consecutive, thermometer and S as in Sudoku – each with interlinked squares between them (which formed the fifth puzzle of the pentathlon). We permuted the four puzzles between the three of us, as and when we got stuck – but the real beauty to this solve was the negative inferences we were communicating between the shared cells, as opposed to only sharing the positive information once that cell had been solved. I got the deficit out by myself, and helped clear up the consecutive as David and George mainly focused on the other two puzzles. Again, we finished before time, scoring 1150/1000 and 3rd for the round.

And that was that. With everything over, and the UK had finished a very creditable 6th best – which bearing in mind the teams ahead of us (Germany, Czech Republic, Japan, Canada and Poland) each featured a member of the individual top 5 together with another pair that give the world’s best a good run for their money. At this point let me say what a pleasure it was to solve with George and David – in what is surely the strongest UK sudoku team.

Now onto the grand finals. Well, not quite. With one of the freebie books handed out by the Turks, I assembled a kakuro showdown between the two greatest solvers of the puzzle on the planet. None other than Jason “Ziti” Zuffranieri and Hideaki “H.Jo” Jo. Jason was to win the main show down, although in another round between myself, George, Jason and Byron I managed to retain bragging rights. Although my puzzle really was very easy. Ish! Hideaki, as always, was incredible humble about the whole thing, it was really good of him to play along bearing in mind the grand finals were just about to happen!

SUper DOKUthlon

The top four finishers were Florian Kirsch of Germany (4th, 1153); Hideaki Jo of Japan (=2nd, 1159); Jakub Ondrousek of the Czech Republic (=2nd, 1159); and Jan Mrozowski of Poland (1st, 1335).

The grandiose Mezzanine halls were cleared out, and set up for a big spectator event. The finalists were up on a stage, solving at tables with spot cameras linked up to a projector so that the audience could see them, using the excellent system that had been in place in Prague. This was improved upon – at least from a spectators point of view – by the addition of commentary as provided by Thomas Snyder and Wei-Hwa Huang.. The downside for the participants is that they were fitted with headphones playing white noise as they were solving, to make sure they couldn’t hear either the audience or the commentary. The one thing I’ll mention about the commentary was that whilst it was mostly enlightening, it did come across as a little patronising at times. This is a thing I have with commentary of any sort: do analysis if you really must, but keep it pared down and to a minimum, and don’t let it interfere with the drama of the moment.

The format was simple. 10 puzzles, various variants, one from each of the ten rounds to solve in the hour. Jan M had a clear points advantage, which translated into an 8 minute head start which pretty much made him the overwhelming favourite. On the other hand, the format of the puzzles arguably favoured Jakub O, if he could manage to hold things together.

The twist in the final came about half way in where it looked like Jan M had completely bottled the consecutive puzzle, spending what felt like an age failing to notice he’d made a massive dickhead error right at the start of the solve. This not only let Jakub overtake him, but he was to get about a puzzle and a half’s lead over Jan. Florian had taken a heavy hit on the second puzzle – a “killer” (which allowed digits to repeat within cages, apparently this is a “local” thing, although no-one quite mentioned where this practice actually occurs) which I thought was a bit of a monster and was effectively out of it; and Hideaki’s all-round formidable puzzle solving skills didn’t quite match up to the raw pace of Jakub or Jan for him to have had a real shot, being at best a puzzle behind. This left Jakub with a lead which seemed large enough to defend with a couple of solid solves.

And then, on puzzle nine, an irregular, Jan pulled off a stunningly quick solve to retake the lead. By the time Jakub had #9 done, Jan had basically finished off the final puzzle, to claim his second consecutive world title. Kudos.

The remaining time spent socialising with the rest of the WSC crowd brought home just why it’s such a shame that these events seem to fly by and we all have to depart too soon. We had a dinner in the hotel again – sharing a table with the Chinese contingent – including Chen “cpickerel” Cen who had finished 7th overall – but who didn’t really speak English; certainly no. Dinner was followed by a presentation ceremony, which was nice; in addition to the winners for team and individual competitions, there were also certificates for the “winners” (highest score of people not in the top 10) of each round. Although to be fair, some – like Jason in round 2 – could claim to have won the round outright.

The rest of Saturday evening was spent in the hotel bar with Jason, the Canadians (alas minus Byron) and Agnieszka (Agush to the Canadians) who’d decided to leave the rest of the Poles to it. I enjoyed this a lot – although sadly this bar had a dearth of any sort of exotic shots. On the Sunday morning I’d managed to lose the rest of the UK contingent, so I decided to hang around in the hotel lobby. Again I bumped into Agnieszka who was with Jan. This was the first time I’d properly met the guy, and despite his fairly broken English we had a good conversation; for a world champion he seems very down to earth. Not that I want to stir anything up, but he said he was really hoping to have a proper showdown with Thomas Snyder at another WSC. That’d be a really great contest!

After that, I eventually got a chance to speak with Nick, Wei-Hwa and Thomas, having managed to miss them completely during the competition. This was an intense, yet hugely enjoyable chat about various aspects of the competition, and how things had went. My vote goes to “very well”!

So there we go. Another WSC over and done with. These things are completely addictive – especially when you feel like you’ve underperformed – and so I refer the reader to the title of this entry. This championship just about shaded Prague in 07 as the best I’ve been to – so a personal thanks goes out to everyone involved in the organisation.


May 28, 2010

Friday Puzzles #52

Well, I’ve made it through a week going at a rate of a puzzle a day. Let me tell you it’s pretty hard going, and I have big respect for MellowMelon for going as long as he did at that rate. I’m now only 2 weeks behind where I’d like my indexing to be – and so you can look forward to a couple more puzzles coming between now and next week. As an added bonus, I’ve seen my weekly traffic increase somewhat. Although I can’t be quite sure whether this is entirely because of the increased rate of publication, bearing in mind the potentially new audience I mentioned my site to at the WSC [And yes, that report IS coming!!!].

One thing I’ve found is that the stricter deadline made my creativity a little forced, and that was definitely the case yesterday, where the nurikabe – as a solve – was pretty lame. When will designers learn that disguising messages into their puzzles doesn’t please anyone? Anyhow, I initially couldn’t make my mind up whether this was a medium or a hard difficulty puzzle, but I’ve gone for hard to be on the safe side. Enjoy!

#062 Nurikabe – rated hard

All puzzles © Tom Collyer 2009-10


May 27, 2010

Friday Puzzles #51

Today’s entry gets an entirely new classification of (ridiculously) easy – for reasons that are (ridiculously) apparent. I must admit this was a pretty self-indulgent exercise that probably rewards me the creator far more than you the solver. All I’ll add is you’re best off solving this in MS Paint – but – Why Oh Why have I coloured in some of the clues?!

#061 Nurikabe – rated (ridiculously) easy

All puzzles © Tom Collyer 2009-10


May 26, 2010

Friday Puzzles #50

So writing a Yajilin puzzle with symmetry gives you all sorts of issues with uniqueness and stuff. Good luck to anyone in the hunt for a symmetric 10×10 with just the four givens! Still, I gave it – symmetry in general that is – my best shot with this one, and I only just failed. Enjoy!

#060 Yajilin – rated medium

All puzzles © Tom Collyer 2009-10


May 25, 2010

Friday puzzles #49

Funny how forgetting to make a puzzle until lunchtime brings out the urge to try new things. Of course, this Slitherlink puzzle is in no way a little bit silly. Just as the titling is by no means getting ridiculous. Oh well – I thought it might be more fun for regular readers to have one a day rather than a huge glut of them on a Friday.

Anyhow, ditto yesterday, this is the first time I’ve ever made a puzzle of this type, and ditto yesterday, if you don’t know the rules, then please check out the “how to play” section on the right. Enjoy!

#059 Slitherlink – rated easy

All puzzles © Tom Collyer 2009-10


May 24, 2010

Friday Puzzles #48

Well, I must admit the titling is getting increasingly more weird for me. Anyhow, I’ve been a bit rushed today – and besides the last few puzzles have been pretty hard – so here’s a let up with something I’ve knocked up in my lunch break. This is a fairly gentle Yajilin puzzle. If you’ve never come across this type of puzzle before, then let me point you to the left hand side of the page where you’ll find a “how to play” section. When I first came across it, I thought (unless the puzzle was really gentle) that it was pretty easy to make a mistake. Hopefully with this one it’s easy to see where you’re going on a global scale and it’ll all fall into place nicely. Enjoy!

#058 Yajilin – rated easy

All puzzles © Tom Collyer 2009-10


May 23, 2010

Friday Puzzles #47

Ooooh – a Sunday. Looking at the time, I think I’m currently drinking myself into oblivion. I’m hoping that this time I can keep myself away from the gin. Gin always gives you one hell of a hangover, and bearing in mind I’m due to be playing cricket later today that’s one thing I could be doing without.

But what better than a drunken puzzle to liven up any party!? Especially one as tricky as this Heyawake. Some careful thinking is required here to avoid tripping yourself up; indeed, that’s why I had to unfortunately break the symmetry of this puzzle to make sure everything was above board. Still, the solve itself was well worth tinkering with to get right, and so that’s why this one gets to be published. Enjoy!

#057 Heyawake – rated hard

All puzzles © Tom Collyer 2009-10

P.S. Incidentally, I thought the Hitori yesterday was harder than this puzzle – but a very helpful testing session with this puzzle has probably changed my mind. Thanks Agnieszka!


May 22, 2010

Friday Puzzles #46

So my attempt to get my numbering back up to where it should be continues.

I was originally going to stick this hitori puzzle in yesterday – it is a much superior puzzle to Friday’s – but I felt it wouldn’t be doing this puzzle justice. I want to talk about this a little bit and that seemed out of place with yesterday’s nostalgic waffle. Suffice to say, some of the logic is quite involved in this puzzle, but what really interested me whilst constructing this puzzle was the whole idea of having so-called “minimal hitori”. The thinking here is that if the numbers in the grid which at no stage feature in any meaningful deduction weren’t even printed in then it might make for a puzzle with a nicer solving flow.

Being the sadistic contrarian that I am, I’ve decided to take a different approach. Most nikoli.com hitori usually feature an “ascending solve” – that is the first deduction will usually be with 1’s, then 2’s and so on. This is true of this puzzle – however what I’ve tried to do with superfluous clues is to disguise them (albeit on a fairly superficial level) amongst what you should really be looking for. Let me reiterate again, this is a tough solve.

Instead of writing “Sorry, Thomas”, I’ll instead go with “Sorry Thomas”. Or perhaps that should simply be: “Enjoy!” :)

#056 Hitori – rated hard

All puzzles © Tom Collyer 2009-10


May 21, 2010

Friday Puzzles #45

It’s funny how quickly a year goes by. It came to my attention this week that actually today’s entry marks the one year anniversary of my Friday Puzzle series. Reading back over the original entry, I’m not sure how successful I’ve been in this not being a massively Sudoku dominated thing – I guess I stick to what I know best and there have been a good chunk of Sudoku or Sudoku variants posted on this blog over the past year. On the other hand, the other two main players have been two puzzles which I really do enjoy – Masyu and Nurikabe – and I hope that I’ve introduced readers into some of the flavours of these two wonderful puzzles.

Now, the eagle-eyed amongst you will notice that 45 is by no means equal to 53, which is the number I ought to be on had Friday Puzzles actually happened on a weekly basis. Alas, various factors have meant that this isn’t the case – not least the break I took at the end of the year. In that post, I recapped on what had been my favourite puzzles so far. I feel obliged to add to that list since then, as there have been a couple of beauties, in my opinion:

  • Week 38: Arrow SudokuOK I’ve seen nicer examples of Arrow Sudoku than this, most notably the WSC puzzle upon which I was moved to write “a thing of beauty” on the page, but this certainly has an interesting visual appeal together with a satisfying solve.
  • Week 34: Masyu – probably the most elegant masyu puzzle I’ll ever write.
  • Week 32: Killer Sudoku – a killer with more than a taste of kakuro, and definitely no cage addition.
  • Week 31: Sudoku – I link directly to this puzzle rather than the blog post, as the excellence of this puzzle was somewhat overshadowed by a more controversial puzzle published simultaneously. [The offence caused was perhaps something I’m not overly proud of now, but I still stand by it given the personal context]. Anyhow, I don’t want to do any more overshadowing here, so be assured that this puzzle is a good’un.

And for the sake of posterity, here are the previous picks once more:

Anyhow, returning to my indexing quandry, I have decided that this week I shall release a “Friday” puzzle daily, until I get up to #52 next week – which should be #54 – and then another two the following week until in two weeks time I should be on course for #55. I might even look at filling in that missing double-toroidal Sudoku I completely forgot about in Week 7; although perhaps the complete absence of Week 17 will be harder to overcome…

I’ve got this far into the anniversary post, without referring to my almost famous off-shoot and pretender to the crown of being the Tom with the original Friday Puzzles series. I’ve hopefully mentioned Thomas Snyder’s blog enough times for regular readers to be familiar with it, but if for some reason you aren’t, you should definitely take the time to have a look – suffice to say there aren’t too many people on this planet like Mr Snyder. Anyhow, in a recent revelation, it turns out he doesn’t much like hitori. Or maybe he does.

Actually, I like to think that last entry was at least in some part induced by a provocative comment I left on nikoli.com, but who knows. This week’s inspiration goes with the whole hitori thing, and today’s puzzle is the warm-up to tomorrow’s full-blooded affair. So not a massively amazing puzzle for the one year anniversary, but hopefully the coming week will make up for it. Enjoy – and thanks to each of my 3,043 unique visitors (since last September when I got Google analytics up and running) for sticking with me so far! :)

#055 Hitori – rated medium

All puzzles © Tom Collyer 2009-10


May 13, 2010

Friday Puzzles #44

One of the comments about some of my Friday Puzzles that I hear from seasoned puzzlers is that they are a touch on the easy side. I have said before part of my aim is to put out puzzles that are primarily friendly to a more general audience. This softly softly approach has the advantage of letting me put out more polished puzzles – the thinking being that as a puzzle writer the time to master quick and easy techniques onto my puzzles is quicker than trying to do a juno.

On the other hand, it has been tempting to flex my muscles a bit, and there have been a couple of puzzles I have released together with a comment along the lines of “expect a similar puzzle in a bigger and better format later”; only for that puzzle never to materialise.

Well, this changes this week – regular readers will no doubt spot the similarities with a previously released puzzle. Here is a nikoli large sized masyu puzzle. Apart from the end being a bit fiddly, I think this is as good a puzzle as I’ve ever written, and I hope you – most dearest of readers – think the same. Enjoy!

#054 Masyu – rated hard

[Click to enlarge]

All puzzles © Tom Collyer 2009-10


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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.


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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Puzzles published on this blog are licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. Please leave a comment or send an email for more information.

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