Friday, 28 December 2012

Friday Puzzles #189

Right, I'm going to end the year as I started, with slitherlink.  I think the theme has come out quite nicely here (perhaps my dearest American readers will have to bear with me), and there's a little bit of bite towards the end of the puzzle as an extra bonus.

See you in 2013 - enjoy!
    #226 Slitherlink – rated medium
All puzzles © Tom Collyer 2009-12.

Wednesday, 26 December 2012

Bonus Christmas Puzzle

The multi-talented Tiit Vunk shared a Christmas themed Sudoku puzzle on facebook the other day and it inspired me to try something in a similar vein.  So here goes!

The Christmas tree itself acts like a fortress.  That is, cells that are part of the Christmas tree must contain digits which are strictly large than digits in adjacent cells which are not part of the tree.  There is no restriction for two adjacent cells which are part of the tree.  Where there is potential ambiguity as to whether a cell is part of the tree, I've filled it with a pale yellow glow.

Each piece of tinsel on the tree indicates an ascending sequence of digits in the cells that it covers.  it's up to you to determine in which direction.  Hopefully it's clear where the tinsel is going.  Please note that some pieces of tinsel are going diagonally between cells.

Finally the tree is decorated with some baubles and a star.  These have no significance other than to provide givens for the puzzle.  Upon test solving in paint, I found these decorations to be somewhat distracting.  I should also add that I haven't tried printing this, so hopefully I've chosen a shade of green that doesn't come out too dark.  Then again you'll have to live with this.  It's a Christmas tree, see.

Oh, and this one isn't for the faint hearted in terms of its difficulty.  But not so hard that you'll need to guess.  But hey, you've all got tons of free time on your hands, right?  Merry Christmas, Dearest Reader, and as always, Enjoy!
    #225 Christmas Tree Sudoku – rated hard
All puzzles © Tom Collyer 2009-12.

Friday, 21 December 2012

Friday Puzzles #188

So last Friday I was too busy to worrying about my viva - the oral defence of my Ph.D thesis - to be spluttering out too much blurb.  This Friday I'm happy to report that I passed (with minor corrections), and so consequently I can now describe myself as that Dr. Tom who posts puzzles on a Friday and is quite good at solving sudoku.

Or at least one of them. ;-)

Today's puzzle is probably just about a medium.  It's definitely harder than #3 of the set I recently provided for LMI.  Enjoy!
    #224 Sudoku – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 14 December 2012

Friday Puzzles #187

Yes, I do have other things on my mind.  No, you don't need to guess.

Wish me luck, Dearest reader; and as always, enjoy!
    #223 Masyu – rated hard
All puzzles © Tom Collyer 2009-12.

Friday, 7 December 2012

Friday Puzzles #186

So the whole WPC series has lost a little momentum, and of the two remaining rounds I was supposed to cover, I was lacking a bit of inspiration.  I've also been writing a ton of sudoku puzzles recently, but you'll soon see some of those over at LMI, and the rest are a much more long term project.

Instead I'm going to provide another Cave puzzle, following the fun I had in putting last week's puzzle together.  And yes, I suppose that is me giving support to "Cave" over "Corral."  I'm not sure I have my head around the difficulty levels of Cave just yet, but I reckon this is probably on the harder side of medium.  I think it's harder than last weeks anyway.  Enjoy!
    #222 Cave – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 30 November 2012

Friday Puzzles #185

Round 10 of the WPC was anthology, but I'm going to use this as an excuse to make a Corral puzzle.  Should I persist with these, dearest reader, bearing in mind Corral is apparently a nikoli puzzle, albeit one with no set of rules I can poach from here?

For now, I'll do what I've done before, and slavishly copy from the WPC instructions.  Enjoy!

Rules: (as taken from the WPC instructions)
Draw a single closed loop, going along the gridlines.  The loop cannot touch or cross itself.  The area enclosed by the loop represents a cave.  All numbers inside the grid must be inside the cave.  A number in a grid cell indicates how many cells (including the cell with that number) can be seen from that cell to the nearest wall in four directions, horizontally and vertically.

N.B. For anyone who hasn't solved these before, don't treat this as your average loop puzzle.  Shading in squares which are either inside or outside (but not both!) is how you will solve these puzzles.  In this respect I'd argue corral has more in common with nurikabe and heyawake than, say, slitherlink or masyu.
    #221 Cave a.k.a. Corral – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 23 November 2012

Friday Puzzles #184

I think I make this round 9 of the WPC.  I think this means that I skipped round 8 as being personally uninspirational, and of course remembering that round 6 was a manipulative optimising team round.  So you won't be getting a puzzle for that round either.

Round 9 was a round of skyscrapers variants, a genre that can be brutally horrible when done wrong, but very pleasing when done right.  With any luck this is a puzzle which isn't totally trivial but still manages to solve nicely enough.  Don't ask me why Toronto comes into the title of this puzzle!  I'm going to push my luck and rate this as medium.  Enjoy!

Rules: (as taken from the WPC instructions)
Place numbers (representing skyscrapers) 1-5 in the grid so that no number is repeated in any row or column.  Each number represents the height of a skyscraper and the higher ones hide the smaller ones behind them.  Numbers outside the grid represent how many skyscrapers are visible from the corresponding direction.  Exactly one cell has to remain empty in each row and column.
    #220 Toronto Skyscrapers – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 16 November 2012

Friday Puzzles #183

My WPC mini-project rumbles on - and I thought it was about time to feature I puzzle that I might normally publish otherwise.  Perhaps it's a sign that I'll eventually finish my WPC report - which incidentally is running in at a cumulative 10,000 words, not out, thus far.  Perhaps it's just a sign that I don't want to go and fish out the WPC script to copy out some rules again.

Anyhow, it's always good fun to poke my head over the uniqueness parapet and serve up a Numberlink.  A puzzle this size can never be described as hard, and maybe not even medium either, but even so I think this one has its moments.  Enjoy!
    #219 Arukone a.k.a. Numberlink – rated easy
All puzzles © Tom Collyer 2009-12.

Friday, 9 November 2012

Friday Puzzles #182

Once again dearest reader, I find myself in something of a rush.  This week's puzzle is going to be really quite easy (alas for uniqueness issues - again!!) if you know the tricks, or else quite a bit harder if you don't.  I'm not sure how well known these tricks are beyond the hardened puzzling community, so I'm going to hedge my bets and call this a medium.  Enjoy!

Rules: (as taken from the WPC instructions)
Fill each empty cell with either a black circle or a white circle.  All white circles should form an interconnected area and similarly all black circles should form an interconnected area.  There cannot exist any 2x2 cell region consisting of same colour circles anywhere in the grid.  There is the same number of black and white circles in the grid.
    #218 Yin Yang – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 2 November 2012

Friday Puzzles #181

...will be delayed until Sunday or maybe even Monday.  Sorry!

EDIT:  This one is for Fred and Prasanna.  Much love.
    #216 Kropki – rated Monstrous
2nd EDIT:  So I'm continuing with my WPC series, and we've made it up to round 4.  The first couple of Easy As ABC Crossword puzzles that I solved were part of the reason I didn't pay much attention to the Half Dominoes explanation during the Q&A session, and it's fair to say that I got the bug for these pretty quickly.  The puzzle I've put together below probably has a couple of surplus clues, but is nevertheless hopefully quite fun to solve.  Enjoy!

Rules: (as taken from the WPC instructions)
Write letters A, B and C in some of the cells in the grid so that each sequence of three or more horizontally or vertically connected cells contains each of the letters exactly once.  Letters above and to the left of some sequences indicate the first letter seen from the corresponding direction.
    #217 Easy As ABC Crossword – rated easy
All puzzles © Tom Collyer 2009-12.

Friday, 26 October 2012

Friday Puzzles #180

So next up in the WPC series.  Colliding battleships is a type from the twisted puzzle rounds, which I enjoyed the most not because I actually solved it in time, but indeed because I didn't and instead drew a giant shark's fin in the grid for the last 30 seconds of the round.  The twist on this puzzle is kind of interesting because it removes a lot of constraints you use whilst solving.  Unfortunately it makes it very hard to set a uniquely solving puzzle.  Sadly for you, dearest reader, it means that I've lost patience trying to put together something of more substance this evening and so this is really only instructional fare.  I am especially appreciative of the skill displayed in constructing the more meaty WPC puzzle!

Rules: (as taken from the WPC instructions)
Locate the position of the fleet shown next to the grid.  The ships cannot touch each other, not even diagonally.  Numbers outside the grid indicate how many cells contain parts of ships in the corresponding row/column.
Note: Only two ships of different size are touching each other!

    #215 Colliding Battleships – rated easy

All puzzles © Tom Collyer 2009-12.

Wednesday, 24 October 2012

Kraljevica '12 day 4: World Puzzle Championship I

I was perhaps a touch late down to breakfast, but thankfully not feeling the worse for wear from the previous night.  Team UK were discussing dominoes strategies, led by James, and which mainly involved abusing uniqueness like a boss.  I sort of nodded my head along without contributing too much to the discussion.  Unfortunately I was in my own little world when it was mentioned that rather than the WPC desks being allocated individual names, only countries and teams.

As we all filed into the room, it was quickly apparent that Neil and James has nabbed the best two UK-A seats.  Perhaps this was for the best as those two were always going to clearly be beating both myself and Liane, but all the same after my positioning in the WSC, I can hardly say I was enamoured to be sat with Bram de Laat directly to my left, Ulrich Voigt directly to my right, Palmer Mebane a few seats back at 7 o’ clock and Hideaki Jo a few seats forward at 1 o’clock.  I will not complain in the slightest about having Michael Ley nearby - not because he isn’t a formidable puzzler too, because he most certainly is - but because before rounds he’d turn round and offer people some boiled sweets to help you going through the rounds.  I have made a note of this and I shall be trying something similar for future competitions.

WPC Round 1: Domino Hunt

So I don’t think I’ve described the bonus structure attached to various rounds throughout both competitions.  The idea was to have a relatively short round which the organisers anticipated people would finish.  If not enough people finished during this time, then a 5 minute extension would apply for everyone.  I think Ulrich did manage to finish in time, but I completely forgot about the extension and was guilty of rushing through the 10 point puzzle, as well of a couple of others.  So whilst I thought I had done reasonably well to have finished all but the last puzzle this round, it turned out that in my eagerness to abuse uniqueness I had made several mistakes.  Three in fact, scoring me 24/60 for the round.

Another short break, and then onto a longer round.  A nice two hour round!

WPC Round 2: Blackjack

This round was kind of cute, with lots of 21 themed puzzles.  In retrospect I think I probably got far too bogged down with the giant octopus puzzle, and only got 10 of the 21 puzzles out.  Moreover I made a silly mistake on the Zebra puzzle - a kind of paint by numbers puzzle which a priori had no connection to 21 but as you solved it revealed a giant pictogram of a certain two digit number.  Anyhow, 65/240 points is probably indicative that this is exactly the sort of round I’ll need to improve upon if I want to better my (so far) modest placings!

Onto lunch.  I was back to feeling dazed, and after finishing in the restaurant headed upstairs to the bar (for a lemonade!) and to get out my puzzle notepad.  I was still aiming to get my little killer puzzle completed and ready for publication on the blog for Friday, but the great thing about these championships is the fact you never seem to be alone for long.  Tiit wandered over and gave us some Estonian puzzle magazine.  Inevitably Jason materialised and before you knew it we were racing again.  I wanted a shot at him on a kakuro (unwise), and a killer (also unwise).  I think at this point Thomas - who was in the background somewhere blogging - had spotted a pattern, but I managed to pull things back to 2-1 with a good slitherlink solve.  I can’t remember the order of the other puzzles, but I think he then took easy as ABC, and I got the battleships and the hitori.  I’d like to think that I got the nurikabe to make things 4-3, but I honestly can’t remember.  I have the horrible feeling Jason probably shaded it.

Clearly I already had bigger things on my mind.  Like:

WPC Round 3: Twisted puzzles

This was basically a round of classic puzzles, where each of the puzzles had a solitary instance where the rules were bent slightly.  So think a kakuro with one cell left empty, or tents where one tree had two tens tied to it.  This round I spent a lot of time not getting the magnets out, and getting bogged down with the four winds with one lying clue, but all in all 48/120 wasn’t quite as disastrous as blackjack.

Still, no time to dwell on missed opportunities, the rounds kept a comin’!

WPC Round 4: Easy as ABC

Strangely enough, this featured no classic Easy as ABC puzzles, instead we a fun crossword variation, a cute snake variation and a somewhat clunky hex grid variation.  Three of each and half an hour to get things done.  Oh, except I don’t think any did.  Except maybe Ulrich (his third finished round of the day incidentally) and so we got the 5 minutes overtime again.  I managed all the crosswords and two of the three hexas, sadly breaking the third.  I get the feeling my time might better have been spent on the snakes, but 36/60 was at least better than half the points available, so not too bad.

Time for a coffee.  Get cup, press espresso button.  Press espresso button again.  Spoon in enough sugar to get a dentist twitching slightly.  Get some water so I wouldn’t dehydrate.  Take a trip to a toilet.  Have a bit of small talk with people sat around me, mainly Bram and Vasso.  Prepare for the next 90 minute round.

WPC Round 5: Black and White

A round with lots of shading!  I got 9 of 15 puzzles out, although as is always the way none of the really big hitters in the round.  Most frustratingly this included a really fiddly tapa puzzle worth 22 points which I just couldn’t tweak, despite probably spending the last half hour trying and failing to get a solution out.  I claimed at the time that I was going to boycott tapa forever and ever - or at least a few months?  Weeks!? - but I’m sad to report I accidentally did one on croco recently.  No mistakes though, so at least that’s something.  57/180 however is probably a score which undersells me.  Again!

That was that for the individual rounds, but as with the WSC there was a half hour break where the room was set up for the team round.  This second day of competition, and the temptation to go up to the bar and get a nice cool refreshing beer was greater than before, but again I managed to resist, instead guzzling down a bottle of coke.  Perhaps I should have had more of a discussion with Team UK regarding the team round, but I kind of hoped James had a bit of an intuition given his thoughts posted on the UKPA forums beforehand.  Anyhow, we got ourselves into position, right next to the German A team, ready for:

WPC Round 6: Marina

So this was just a giant optimisation puzzle where you had to place plastic boats on a massive grid with a marina drawn out.  Various bits of the marina had different (x5, x3 and x2) multipliers, and there were a few convoluted rules about making sure that every boat had enough space to individually get out.  I’d like to say we had a strategy, but what ended up happening was the four of us took a corner of the grid, filled it up, and then rotated round to start tweaking.  At the time, we had no idea how successful this would be, but I think it worked out OK because despite accidentally placing too many of one particularly type of ship, thus losing easy points, we finished slap bang in the middle of the pack.  Of course we were only to find this out much later; instead we left the competition hall feeling pleased with the detour from churning out puzzle after puzzle.  An optimisation problem of course needs a good sense of what is going on, but there is necessarily a large intuitive component to getting a good solution out.  Interestingly enough, AJ had a different perspective on things.  Since you had no idea how well you had done as a team, there was a lingering dissatisfaction for him.  On reflection I can certainly see how you’d think this.

For dinner, I think other members of team UK were efficient enough to grab a big enough table that we could all squeeze around, which was nice as typically we had to split our rather large contingent over at least two tables.  As per normal dinner lingered on before everyone slowly migrated upstairs to the bar.

Initially things were a bit quiet, Fred and Bastien were chatting away, and Bram was probably sat there with his laptop putting up something for his blog.  I think he’s unrivalled for the amount of practice material he prepared, and I took the chance to catch up with what Thomas and Palmer had had to say on their particular little patches of the internet.  I certainly got a chuckle reading about Thomas sleeping with socks on his hands to stop the insects biting in the night; thankfully I had no such problems with my room.

I had also managed to get the little killer for my blog, and set about formatting it up.  As a professional graphic designer who knows nothing other than Illustrator I got to introduce him to Inkscape, of which I am very fond of, even if you have to run it under X11 on a mac.  Neil was naturally curious and so I got him to have a go at solving it, challenging him to get it done before I came to giving it a rating.  My dearest readers are invited to look back at that particular blog post to see whether he managed this challenge.  Fred and Bastien came over and made lots of useful and helpful and particularly delightful comments about symmetry, and much laughter was had at my expense!

Inevitably the bar session reverted into another puzzling showdown, again with Yuka’s excitingly presented sudoku magazine.  I should mention this was doubly novel for me as the magazine read from back to front!  After the previous night’s experience, I think Bram had rightly been concerned about joining forces with me again, and so instead formed a formidable trio with Jason and Tiit.  My trio, presumably motivated by a desire to laugh at me some more, featured my two favourite francophones.

Having used up the actual relays in the magazine the previous evening, we had to improvise somewhat, and ending up flicking to the back of the magazine.  Or front of the magazine I should say!  We found a two page spread of classic sudoku, ominously labelled with numbers ranging from 40 to 70.  What could these numbers mean!?  Anyhow, the format this time round would be 3 individual solves, 3 paired solves and then 1 with all three of us.

Getting stuck into the puzzles it quickly became apparent that the “mysterious” numbers could only be time targets.  I was up first and so thankfully had the easiest puzzle.  I actually made steady progress through this one, and let out a half-delighted “x-wing” as I managed to get the puzzle up.  My opposite number, Tiit looked up and asked firstly whether I had guessed, and secondly whether I had made a mistake.  I’m not sure he was  totally convinced by either of my denials!  Anyhow, after these puzzles the difficulty ramped up and everyone was using things like forcing chains and other solving techniques that should never see the light of day in competition.  Beyond x-wings, swordfish, xy-wings and simple colouring I’m afraid I’m not much use here - although the x-wing I spotted that led to no digit being placed was met with more (!) laughter from Fred.  I think he was especially appreciative of the help I could offer after he’d cracked the hard part of the puzzle where I would point at the grid and say “two.”

At some point it reached about half 1 in the morning, when Bram said that he’d regretfully have to pull out of our self-inflicted sudoku painfest as he (rightfully!) argued he didn’t want to compromise his 2nd day of competition.  Unless you count the excellent spectator sport of endless mockery directed at me by Fred and Bastien, I can safely say that he missed nothing!

Friday, 19 October 2012

Friday Puzzles #179

So I've not really been able to pick a stand-out puzzle from the WPC like I could from the WSC.  I think what I'm going to do is release my favourite puzzle from various rounds and then maybe do a vote or something for your favourite in a few weeks time.  What I can tell you now is that I'm not going to do a dominoes puzzle, and unfortunately the puzzle I have in mind from round 2 has uniqueness issues, so you might have to wait until tomorrow until this gets published.  Hey - at least I got this disclaimer out on Friday.  Ugh.  Sorry!

UPDATE: I suppose I should add fair warning.  I tested this puzzle after 5 pints of Guinness last night, and I was very pleased with the logic that I thought made this solve uniquely.  I'm not so confident that this has a unique solution now, but I have no time to re solve it at this moment in time as apparently I'm wanted on television.  Given the issues I had with uniqueness making the bloody thing I'll not be surprised if someone finds a second solution here...

Rules: (as taken from the WPC instructions)
Place some tiles (of size 1x2 squares) in the grid, with numbers 1 and 2 each.  Tiles can be rotated but they cannot touch each other, not even diagonally.  Numbers outside the grid indicate the sum of all the numbers in the corresponding row/column.

    #214 2-1 Tiles – rated hard
All puzzles © Tom Collyer 2009-12.

Thursday, 18 October 2012

Kraljevica '12 day 3: Excursion

The rest of day 3 was to provide a respite from the intense day of competition on day 2, which I certainly welcomed.  We were to be bussed away on a series of coaches to have a tour of the nearby city of Rijeka.  Waiting for these buses to arrive, I found myself in a brief moment of solitude sitting in the sun, and was joined by multiple WPC champion Wei-Hwa Huang.  Wei-Hwa is something of an oasis of calm within the US ranks, and I can only imagine how much of a pleasure solving the sudoku team rounds must have been for them with him directing the solve.  I asked how things were within the team ranks and how his own preparation was going, and found his reply to be quite telling.  Being on a team with the twin peaks of intensity provided by Palmer and Thomas apparently rubs off on even the most phlegmatic of characters, and so whilst Wei-Hwa stated he was just here to have some fun, he also mentioned he felt a little pressure to get some preparation in just to keep his head above water.  We were briefly chatting about the various travel opportunities puzzling was providing us, when fate dealt a cruelly ironic blow, and Wei-Hwa pointed out that if I wanted to go on the excursion I should probably head over to the buses.

So I was conscious of the fact the tour guide on the bus was saying various things on the bus as we headed towards Rijeka, but as with last year I took the opportunity to whip out my notebook and get working on the little killer I was intending to publish on the Friday.  I’d had a good idea, but couldn’t quite flesh it out by the time we arrived.

There we were, probably in excess of 100 puzzlers on tour let loose in the city, which to be honest was quite a surreal experience.  We were loosely being guided by the tour guides who’d been on the buses through the landmarks of Rijeka, which firstly included some sort of a church which I presume from wikipedia was Svetište Majke Božje Trsatske.  This loosely translates as being a “sanctuary,” but the main church bit was far from tranquil as the puzzling horde invaded!

The next stop off was some sort of fort, with a good view of the city below but which was otherwise fairly unremarkable.  That said, it did provide the first starting of the German Michael Drinking Unit (Ley and Smit), who seemed to be sat down in every bar with a cigarette and a refreshing beverage to hand at every turn during this excursion!  After we’d all had our fill of the castle, we trudged back to the buses to be taken down the hill and into the city proper.  On the walking tour, I can’t claim to have been paying much attention, although I was quite amused when a fairly unimpressive arch was pointed out as having once thought to have been a triumphal arch (I can’t for the life of me think why when you compared this to say, Rome, Paris, or Barcelona for example...) and instead turned out to be an entrance to some Roman building.

Anyhow, I latched on to a group with the Americans and Prasanna.  Being hugely cultured individuals, we decided to pay our respects to another of Rijeka’s magnificent arches - or should I say golden arches?  Anyhow, I was of the opinion that it was quite hot and humid and it was high time to follow the lead of GMDU and find a nice place to sit down.  Whilst apparently Prasanna and Thomas were talking about the slim likelihood of me being able to roll out of the gutter and back onto the bus, later, I was having a good chat with Nick Baxter, Rodders and Will Shortz about far more important things: namely sport!  Not that I care all that much, but apparently the Ryder cup was still something of a sore point for Nick and Will.

As much as I’d have like to have lingered in the bar doing my best to fulfil Thomas’ prediction, we soon had to move back to the bus, to be taken to some hotel for a dinner, and the WSC closing ceremony.  Entering the hotel, we offered a choice of aperitifs (oh how I love mystery Eastern Europea spirits!) before I broke ranks with team UK and plonked myself down on what was to turn out to be the American table.  I should probably state that I’m all for team unity and the rest of it, but these championships come round once a year and I think it’s a waste not to go a mingling with everyone else - and it’s not as if for most of the breakfast/lunches/dinners at Uvala Scott weren’t being spent with the team.  Instead I found myself speaking about “math” with Josh Zucker (JZ mk II!), JZ (mk I) and Anderson Wang.  I think I managed to amuse them with my “talent” for factorising quadratic equations with integral coefficients by eye rather than an anything more pedagogical, but I was definitely pleased to employ some geometric group theory to help confirm an answer to a fiendish triangle counting puzzle Wei-Hwa had come up with.

The dinner drifted pleasantly by with the wine flowing and more puzzles appearing on the dinner table, before it was time for the prize giving ceremony.  The Poles were obviously jubilant with Jan’s victory, and had seemingly managed to acquire several of the aperitif bottles in preparation for a long night!

After the prize giving I thought it was probably best to say hello to Mike Colloby and Alan O’Donnell, who were the last of team UK to arrive having only just been driven in with Stefano.  Alan was participating on the WPC B team, whereas Mike had the important job of presenting the British bid to host the world championships in 2014.  I also managed to congratulate George Wang on the Chinese success.  Rereading an article he penned for I think the 2007 WPF newsletter it is remarkable to think how far puzzling in China has come in the last few years!

Being a little tipsy at this point, I stumbled onto a different bus to be driven back to Uvala Scott, which turned out to be a good thing as on it were both the victorious Poles, as well as a few of the Japanese.  Moreover, there was still plenty of the bottles of spirits going around, and Kuba took itself upon him to conduct the drinking on the bus, walking up and down the aisle inviting everyone to swig with him from the bottle.  Outstanding!  Needless to say, this wasn’t an opportunity the legendary Tetsuya Nishio was going to pass up on, and there were shouts of “Kampai” and “Na zdrowie” all round.

The remaining business of the day was to be held in the bar back at Uvala Scott.  Yuka Noyama had very kindly given me a copy of a rather exciting looking Japanese sudoku magazine - which was in stark contrast to anything you might find on sale here in Britain - and I had suggested that Jason go find so we could set up some racing!  In retrospect, it should probably not have surprised me as to how bad I was going to be, but I thought a relay team of myself, Gaurav Korde and Bram de Laat should have easily had the beating of Jason and the Greeks (perhaps they were Argonauts?).  The early running was good as I finished the first puzzle a minute or two ahead of Jason; I have a picture of him still working to prove this, ;-)  but things were to level out as some drunken idiot kept making mistakes.

The only thing for it was to grab another beer, and chat with the Poles for a bit before belatedly realising there was like some important competition or something due to be starting in the morning, and that we should probably attempt to get some sleep.  Or something!

Wednesday, 17 October 2012

Kraljevica '12 day 3: WSC play-offs

When I woke up I think it’s fair to say that, despite not knowing the overall results, I was fairly confident I hadn’t hit the heights of the top 8 and so would almost certainly not be participating in the WSC play-offs.  Now, an awful lot has been said about the format of the play-offs this year, but I am going to save any more detailed analysis to a future series of blog posts discussing the matter where I hope to engage the community at large.  Instead, I’m going to focus on describing them from a spectator’s point of view.

Kraljevica '12 day 2: World Sudoku Championship

For previous championships I have the feeling that arriving before about 10 in the evening gives you sufficient time to settle down, because I hadn’t quite woken up on the morning of competition with the usual butterflies in my stomach.  I’d woken up at 8 and was showered and changed and down in the restaurant a half hour later, and still nothing.  I can’t say I was particularly enamoured by the breakfast either.  The whole cold breakfast meats with bread and mustard wasn’t particularly what I wanted so in the end I plumped for some cereal.  It didn’t seem to make a difference between the yellow supposed corn version or the brown supposed chocolate version - both ended up being fairly cardboard-y.  Nothing very liberal sprinklings of sugar couldn’t fix!

Sunday, 14 October 2012

Kraljevica '12 day 1: Arrival

So given some of the troubles that my fellow competitors had in getting to the Uvala Scott resort near Kraljevica, Croatia, I’m not going to linger too much on the blissfully pleasant time I had in Trieste waiting for the bus to transfer me.  The sun was shining, it was warm, we had had a gorgeous lunch up in the hills outside Trieste before coming down to enjoy a lingering coffee on the Piazza Unità.  Paradise!  There was momentary concern about whether the bus was actually going to show up at 5pm at the railway station, but after meeting up with a few other equally concerned puzzlers, it was quickly established the bus was at the nearby coach station instead.

Our route to Croatia had to backtrack to Trieste airport, where we picked up a few more puzzlers.  It was great to meet up with some of the Japanese contingent, Yuhei, Kota and Yuka, who had been been making a big detour through much of Italy as part of their journey as well as the Greeks - formidably led as ever by Vasso - and my old drinking buddy Jason of the US.  One of the great things about these championships is the chance to meet up with so many different people from different countries, but it is always nice to speak with someone who as English as their mother tongue.

Our merry busload didn’t even notice the Italy-Slovenia border, but at the Slovenia-Croatia border a chap came on board to inspect our passports.  I briefly wondered what he thought of our particular medley, but was more thankful that my middle names were remarkable for there being two of them rather than what they actually are.  I was also amused by the proliferation of weather symbols dispersed across the new British passport.  There was one further stop at some services, which seemed a little unnecessary given we were about half an hour away from the place, but it did give us a chance to stretch our legs and for Jason to purchase a bag of what I assume were sweets but were entitled something very close to the word scrotum.  Interestingly enough this was the last I heard of this particular bag of treats...

We finally arrived, turning a corner with a sign pointing towards a “sport disco” (my guess was rugby) and Uvala Scott.  Disembarking, we formed a nice orderly queue to receive our room keys.  As it was dark I couldn’t really get a feel for the place, but as I handed over my passport I noticed that this hotel’s key was actually a physical key, and on walking up to my room in the dark that this hotel was more like a concrete version of Butlins.  Oh well.  It’s not like the trip advisor reviews had been glowing, and quite frankly I end up spending as little time as possible in my room at these championships as is possible anyway.

I wandered down to the main bit of the resort, with the bar and the restaurant and the competition hall.  In the competition hall, the Q&A session for the sudoku championship was about to get underway, but I was pretty hungry at this stage and instead chose to grab some food from the restaurant.  As in previous years, the catering model was an industrial scale buffet - albeit one sorely lacking in both quantity and quality of cakes - which meant that the food wasn’t going to be particularly great, but at that particular moment in time I didn’t really care.  I passed over the complimentary glass of bubbly, which apparently couldn’t leave the restaurant, but bought a bottle of beer, which could, and headed over to the Q&A session.

I met up with the UK team, which at this point of proceedings consisted of the official A team, featuring Neil Zussman, Roderick “Rodders” Grafton and Michael Collins, as well as the two ladies, Liane Robinson and Emma McCaughan, who were unofficial B-team participants.  Liane pointed out that with spectacular timing I had arrived just as the questions had finished.  Not that that really mattered, I only had one minor query about whether a diagonal constraint was going to be present on the little killer (more on this later!) but otherwise the instructions seemed to be fairly self-explanatory.

We stayed and chatted on for a bit longer before deciding it was probably a good idea to head off to bed.  And I’d like to say that was that for the first day, but this would be to do discredit to a magnificent thunder storm that manifested at roughly midnight.  I’ve never experienced a thunder storm by the sea before, but I can tell you it’s quite an experience!  The lightning reflects off the sea and lights up the sky for miles and miles, and the thunder booms down, rumbling across across the water until it hits the shore and physically shakes the room.  Needless to say sleep wasn’t going to happen until Zeus, Thor, Perun et al had had their fun, and so whilst they were busy with all of that, I decided to have some fun of my own.  With a puzzle book.  ;-)

Friday, 12 October 2012

Friday Puzzles #178

So I'm back from Croatia, dearest reader, and as promised I've made a homage to one of my favourite puzzles from the WPC.  It is a somewhat curious fact that this puzzle type didn't feature in any of the competition rounds, but was instead introduced to me after hours in the bar by my good friends, the merry Polish puzzlers.  Whilst the actual competition is one of the most important thing at these championships, it is my humble opinion that the socialising afterwards with fellow puzzlers is equally as important.  Anyhow, as is always the way with these things, broadly sweeping statements were made by all concerned and before I knew it I was committed to broadcast this wonderful innovation to the world.

Now as I'm sure all my dearest readers now, detuned radio is very much a blog that promotes family fun, but I fear that this week we will be pushing things to the limit.  However I'd like to think that if nothing else, I am a man of my word, so here goes.  Please bear in mind I've had to give a few aspects of this puzzle a slightly different description!

Place some 1x3-cell rectangles of either orientation, and some circles (contained in a single cell) into the grid.  Rectangles may not touch rectangles, and cells containing circles may not touch cells containing circles, even at a single point.  Each rectangle must orthogonally touch 2 circles, to form a T pentomino, and each T pentomino touches a further circle at its base, so that there is a set of several disjoint hexominoes of the same type in the grid.

(N.B. I'm not sure if there is a standard labelling of hexomino types by letters given there are 35 of them, but the one I have in mind is definitely the one that looks most like a capital T.  With apologies to my illustrious e-mail correspondent for the previous ambiguity!)

Numbers outside the grid indicate how many cells in the corresponding row or column are used by rectangles.

If things aren't beginning to become clear, just be thankful this type probably isn't going to feature as a manipulative team round any time soon.  Ahem.  Enjoy!
    #213 Bit of a T's – rated easy
All puzzles © Tom Collyer 2009-12.

P.S.  I'll put up a puzzle which did feature in competition next week!
P.P.S.  Expect some lengthy championship reportage soon!

Friday, 5 October 2012

Friday Puzzles #177

Greetings from Croatia, where it's great to be in the company of the international puzzling fraternity.  Some things never change though, and again I find myself on a Thursday night formatting up a puzzle ready for publication.  The WSC has been and gone and washed me up in 28th place, which I'm satisfied with even if I was aiming to break into the top 20.  There's always next year!  Team UK finished the team competition in 12th, which is modest progress on last years 14th, and all the more creditable in the absence of David McN, who sadly had too many commitments to make it out this year.  I look forward to trying to get one over him at next year's event!

Congratulations are due to Jan M of Poland for taking his 3rd title, and to the Japanese all-star team for running away with the team title.

Anyhow, onto puzzling matters.  My idea was to take my favourite puzzles from both the WSC and the WPC and provide my own humble homage.  I thought a lot of the puzzles from the WSC were if not disappointing, then no better than mediocre, many seemed to have come from straight out the generator.  From an aesthetic point of view, it was a little disappointing to observe a distinct lack of symmetry in the play-off puzzles.  The one difference was a little killer puzzle which was a lot of fun to solve.  Perhaps at this stage I should mention that that puzzle, as well the one below, does not require there to be different digits on the main diagonals of the grid.  Perhaps I should also mention that I've got Neil Z sat across the table test solving, and he hasn't managed to crack it yet.  On that basis, this gets a "hard."  Enjoy!
    #212 Little Killer Sudoku – rated hard

All puzzles © Tom Collyer 2009-12.

Friday, 28 September 2012

Friday Puzzles #176

I'm massively hungover, and I should really be going through the WSC/WPC booklets.  I'm really looking forward to seeing lots of good friends in Croatia next week.  With any luck I'll put together some live blogging whilst I'm there too.  For now, here's a not hugely inspired heyawake puzzle.  Enjoy!
    #211 Heyawake – rated easy
All puzzles © Tom Collyer 2009-12.

Tuesday, 25 September 2012

ChipIn for Children's Charities

With apologies to Grant for forgetting to publicise this on Friday, better late than never I hope!

Anyhow, I'd like to point all my dearest readers towards one of the oldest and best puzzle blogs, A Cleverly-Titled Logic Puzzle Blog.  Grant is currently running a raffle style contest with some cool prizes, and heavily incentivising you to donate to three charities that are close to his heart whilst you solve.  The more money you donate, the more raffle entries you get!  And as an extra incentive, the more each of the three charities receives, the more giant-sized puzzling fun Grant will supply as he approaches his 600th (!!!) puzzle.  He's currently at #569, see here for more details.

It's all in a good cause, and any contribution will be appreciated even more than you'll appreciate Grant's great puzzles.  Which is quite a lot!

Friday, 21 September 2012

Friday Puzzles #175

Sometimes it's handy having 40+ minutes of a competition round to sit in silence when you want to make a puzzle.  As with the majority of my sudoku, this one is pretty easy despite having no clued 9's.  If you are playing the speed solving game, less than 3 minutes is good, less than 2 minutes is very good and 90 seconds is probably world leading.  Enjoy!
    #210 Sudoku – rated easy
All puzzles © Tom Collyer 2009-12.

Monday, 17 September 2012

2012 Times sudoku championship write-up

Long story short:  a permuted 2 and 8 in R4C1 and R5C1 in puzzle #6 cost me a place in a grand final that, given my subsequent solve on the sidelines in 14 minutes and 25 seconds, I'd have probably won.  Still, I think the long story is worth it, so you'll have to allow me to indulge my writing whims dearest reader, and we'll walk down this cathartic road together.

Friday, 14 September 2012

Friday Puzzles #174

A quirky heyawake puzzle this week, probably just about medium in difficulty level.  I don't have time to say too much more than that; enjoy!
    #209 Heyawake – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 7 September 2012

Friday Puzzles #173

So the nice thing with slitherlink puzzles is that there always seems to be a way to accommodate new ideas.  The not so nice nice thing is that trying to make a moderately difficult puzzle throws up lots of uniqueness issues.  Getting round those can be a pain in the arse, and this isn't quite as full blooded as I'd intended, but I think this probably just about deserves its label of hard rather than medium... but only if you resist the temptation to guess or (ab)use uniqueness, it's only a small grid.  Enjoy!
    #208 Slitherlink – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 31 August 2012

Friday Puzzles #172

Rather excitingly, I passed 10,000 page visits on the blogger platform this week.  I seem to be getting slightly less traffic here compared to Warwick blogs, and markedly less traffic from the UK, which probably makes sense considering all the internal traffic I used to get there.  Still, it'd be nice to see the UK numbers go up, especially with the Times "Su Doku" Championship coming up in September.

For now, I'm going to stick with what I am best at.  Or at least can pull out of the bag with the most ease.  I bet you might even secretly enjoy them, dearest reader, even if you know that if you say so will only provoke me to make more.  Haha... although I'm not sure that'd be possible.  Maybe as an extra challenge, you can work out which clue (I think there is only one) which is superfluous.  Enjoy!
    #207 Masyu – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 24 August 2012

Friday Puzzles #171

Tom Collyer tries to improve Slalom #1.  Two easyish puzzles, but I think the innovation of shrinking down the posts, thus having more space for the loop to take up as much area as possible in an effort to combat some uniqueness strategies, is a good one.  I'm not sure how elegant it all looks, but perhaps that's more to do with my placing of the gates.  Let me know what you think - and enjoy!
    #205 Slalom – rated medium

    #206 Slalom – rated easy
All puzzles © Tom Collyer 2009-12.

Friday, 17 August 2012

Friday Puzzles #170

So what with having a thesis to finish off ASAP, perhaps, dearest reader, you'll forgive me for being a little obsessed with joining up fragments of loop in (sometimes punctured!) topological discs.

I've also been pondering the similarities and the flaws in two seemingly different puzzles: Slalom (or Suraromu to give it its imperfectly Anglicised title), and Bahnhof.  The latter is not German in origin - I've used Bahnhof purely because I had only ever seen the puzzle on the German based croco puzzle website - and roughly translates to "Railway Stations."  Rather simpler would have been to use the title "Railroad Tracks" - thanks motris for setting me straight on this one.

Anyhow, the idea to Bahnhof (I'm going to stick with that rather than make more drastic edits to the post, that's just the way it's going to be for now) is simple: draw a single loop in the grid using all the cells, and so that the loop travels through each numbered "station" without turning and in order.  The loop is only allowed to cross itself at marked intersection points.

I'd like to take elements from both these puzzles to try and get past some of the flaws to both.  I don't much like the intersection points in Bahnhof; pretty much every Bahnhof puzzle I've solved seems to use these as  the main break-ins to the puzzles.  I also don't like how most puzzles only very loosely use the ordering constraint.  Slalom, as I'm sure I've blogged before, is a beautiful idea for a puzzle making strong use of the ordering constraint, but it is somewhat crippled by its susceptibility to uniqueness strategies, in much the same way that Numberlink thrives upon them.  I'm not sure the constraint of using every square a la Bahnhof is the way to save Slalom but watch out in the future for some attempts to reconcile everything nicely.  For now, here are some plain old Bahnhof puzzles, without crossings.  Enjoy!
    #203 Bahnhof – rated medium
    #204 Bahnhof – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 10 August 2012

Friday Puzzles #169

This week I have learned that drawing shapes in heyawake is somewhat easier than drawing shapes in nurikabe.  That 2 and 7 there on the left should probably be closer together, but given that it's now a quarter to three in the morning I do declare myself happy with this puzzle.  Enjoy!!!
    #202 Heyawake – rated hard
All puzzles © Tom Collyer 2009-12.

Friday, 3 August 2012

Friday Puzzles #168

So this link is only going to look vaguely impressive until the 10th of August, after which you'll have to scroll down to number 141, but I'm quite proud of this one, despite "only" finishing 3rd behind a couple of Japanese solvers with championships already to their name earlier in 2012.  Hurrah!

So a fairly easy choice of puzzle type this week.  I've only gone and spoiled you with a slightly larger puzzle.  Was tempted to try something with twisted symmetry, but any sort of symmetry went out the window when the main motif I wanted was 8 cells high and 17 wide.  It's making for quite a nice theme for the next week or two though.  Enjoy!
    #201 Masyu – rated hard
All puzzles © Tom Collyer 2009-12.

Saturday, 28 July 2012

Friday Puzzles #167

What do you know?  I've reached a landmark without realizing it and made a special for the occasion!

The grids from left to right are:  Classic Sudoku, Diagonal Sudoku, Windoku, Irregular Sudoku and Non-Consecutive Sudoku.  Where grid overlap, so do the extra rules (although note that this still means a digit in the irregular grid adjacent to the non-consecutive grid is allowed to be consecutive).  Enjoy!
    #200 Olympic Sudoku – rated hard
All puzzles © Tom Collyer 2009-12.

Friday, 20 July 2012

Friday Puzzles #166

So first things first - last week's experiment.  Perhaps all will become clear if I permute [in disjoint cycle notation: (163754)(29)] the labels of the givens of the second puzzle, and rotate the grid.

I'll leave the column switches to your imagination, but yes, that's right, I gave you essentially the same puzzle to solve twice.  By the same, I mean isomorphic - which is just a fancy way of saying there a set of grid manipulations you can perform on one puzzle to get to the other.  For the record, they are:
  • Relabelling.  That is, applying a permutation to the givens.  There are 362,880 (=9!) of these.
  • Dihedral symmetries - which is a fancy way of saying rotations and reflections of the square grid.  There are 8 of these.
  • Outer Box shuffles.  Probably best highlighted by an example.  Imagine taking rows 1, 2 and 3 from the top of a puzzle, and sticking them on the bottom of the puzzles so they become rows 7, 8 and 9.  Any analogous operation which preserves the 3x3 bold grid defining the 3x3 boxes counts as an outer box shuffle.  There are 36 (= (3!)^2 ) of these.
  • Inner Box shuffles.  Again I'll highlight this with an example.  Imagine taking rows 1, 2 and 3 and shuffling them so they become rows 2, 3 and 1.  Any analogous operation preserving a 3x9 or 9x3 section of the grid whose boundary is part of the 3x3 bold grid counts as an inner box shuffle.  There are 46,656 (= (3!)^6 - count 'em!) of these.
Notice that you can get a horizontal or vertical reflection via a series of both types of box shuffles, as well as a 180 rotation, although you can't - thanks Thomas - get a 90 rotation.  Put another way, there is a total of 1,218,998,108,160 (not counting any further symmetry within the partitions in the grid) things you could possibly do to turn one sudoku puzzle into a sneaky doppelganger.  Those are the sorts of figures one normally associates with national debts....

Now, I'm not going to do any formal analysis on the times everyone kindly reported to me.  I suppose for one thing I'd probably need in the order of 100's or 1,000's before being able to say anything worth saying.  However, my theory was that since both puzzles were isomorphic, the second puzzle people solved would be slightly faster than the first.  There ought to have been some sort of subconscious familiarity whilst solving, because combinatorially you could exactly the same thing to get to the solution!

I think it's fair to say that it didn't quite work out like that.  Granted, I put a little effort into making the puzzles seem as different as possible, but the varying times seem to indicate that exactly how the grid is presented makes a difference as to how people have solved the puzzles.

I guess the other interesting thing is that many good puzzle solvers completely missed what was going on, despite the meta-signpost of an experiment with two rather innocuous puzzles.  Perhaps some sorts of grids are more open to this sort of thing than others.  Anyhow, I'm going to leave the story there for now, but perhaps you'll be hearing more on the subject from Thomas S or Grant F in future weeks.

This week's puzzle is something completely different - Yajilin.  I made this hungover, and in rather a bad mood yesterday so don't be expecting too much, but do watch your step.  enjoy!
    #199 Yajilin – rated easy
All puzzles © Tom Collyer 2009-12.

Friday, 13 July 2012

Friday Puzzles #165

This week dearest reader, I invite you to come with me on something of an experiment.  Indeed, I spoil you - there are two sudoku puzzles for your puzzling enjoyment.  If you'd like to indulge my curiosity, then what I'll need from you is the following.  Firstly I'll need your solving times for both puzzles, and secondly I'll need the order in which you do the puzzles.  How you decide the order is entirely up to you.

Anyhow, if you could leave a comment below, or on facebook, or maybe even just e-mail me that would all be simply marvellous.

On the other hand, there's no pressure to do any of that.  Either way, enjoy!
    #197 Sudoku – rated easy

    #198 Sudoku – rated easy

All puzzles © Tom Collyer 2009-12.

Friday, 6 July 2012

Friday Puzzles #164

So I've been a little busy recently to get around to fully publicise this, but I've recently finished putting together the July edition of the UKPA beginners contests.  I say contest, but this month we've decided to go all open access and remove any need for registration or password.  Unfortunately this means there isn't any online answer entry this time, but we're working on an anonymous just-for-fun version for unspecified future contests.

Read more about it all here:

Anyway, the puzzles featured are Battleships, Masyu and Skyscrapers.  And what do you know, I have another Masyu for you this week, dearest reader.  Easy - but only just.  Enjoy!
    #196 Masyu – rated easy
All puzzles © Tom Collyer 2009-12.

Friday, 29 June 2012

Friday Puzzles #163

I'm not too sure what to make of this kakuro, but it has its moments.  Enjoy!
   #195 Kakuro – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 22 June 2012

Friday Puzzles #162

Who likes Hashi anyway?  I must be getting old, or something.  I guess I could really have sent this one to 11 with a little more time, and I daresay a little less drink, but this one has ended out a little tame.  Still, I reckon this little fella is cute enough to post, especially given the dearth of any vaguely interesting hashi puzzles, well, anywhere.  I suppose it's moot as to whether this is an exception to that particular rule, dearest reader.  Enjoy!
    #194 Hashi – rated easy
All puzzles © Tom Collyer 2009-12.

Friday, 15 June 2012

Friday Puzzles #161

Sudoku this week, and I guess inevitably easy - I was initially joylessly working with a sub-pattern of 20 givens.  So few givens definitely requires a good eye for a pattern and no lack of skill as constructor to pull off, but I'm not feeling it this week.  So the puzzle features an initial head-scratch and a fluster of digits falling into place, which I suppose is also becoming something of a trademark.  See if you can't get this done in under 5 minutes - and under 2 if you're feeling competitive.  Enjoy!
    #193 Sudoku – rated easy
All puzzles © Tom Collyer 2009-12.

Friday, 8 June 2012

Friday Puzzles #160

This Nurikabe seemed like a good idea at the time. Enjoy.
    #192 Nurikabe – rated easy
All puzzles © Tom Collyer 2009-12.

Friday, 1 June 2012

Friday Puzzles #159

So it's a bit of a first this week, dearest reader, as we depart from a nikoli staple and instead try something different.

The idea of skyscrapers is this.  Fill in the grid so that each number from 1-N appears exactly once in each row and column, latin square style.  Each digit represents the height of a building, with bigger buildings blocking smaller buildings.  The clues on the outside of the grid tell you exactly how many different buildings are visible from that direction - so for example a row containing 123456 has 6 buildings visible from the left, and 1 from the right.

This was going to appear in the next version of the UKPA beginners contests.  By the way, if you haven't had a go at this month's contest, why not!?  Registration is quick, easy and free!  Anyhow, this puzzle was probably a little much for one of those, but I'm sure it'll be appreciated here.  I'll stick a hard label on this seeing as it is the first one, just to be safe.  Enjoy!
    #191 Skyscrapers – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 25 May 2012

Friday Puzzles #158

This one goes out to those 13 wonderful facebook fans I have.  Yes, that's right, as many as 13!  I don't think I've plugged that for a while, so why not scroll down a bit and click that like button.  What's the worst that can happen?

By the way, on the plugging theme I cannot recommend more highly the super-duper UKPA beginners contest I put together.  12 puzzles for you to have a go in the time frame of a month - and you don't even have to do them all in one go.  Feel free to keep coming back and  submitting your answers at your own knowledge.  And then see how you did at the end of month.  That's something I can't manage to offer my dearest readers here!  What exactly do you have to lose, eh?

Right, it turns out I do have a limit on my own shame, so I'll get straight onto this week's puzzle.  Nurikabe, with a little bit to think about, in my own slightly fiddly and time-honoured fashioned.  Enjoy!
    #190 Nurikabe – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 18 May 2012

Friday Puzzles #157

So this post completes the 3rd year that Friday Puzzles has run.  How time has flied, dearest reader.  But you know me, no great fanfare here, I'll just keep plodding on as best I can and hope that people enjoy the ride.  This week, heyawake.  First one of these for a while. and ought to be fairly plain sailing.  Enjoy!
    #189 Heyawake – rated easy
All puzzles © Tom Collyer 2009-12.

Thursday, 17 May 2012

UKPA Beginners Contests

Well, I'm spamming this just about everywhere else I can think of.  Anyway, if you've never done anything like this before now is the time to start!

The UKPA is pleased to announce a new monthly series of "Beginners Contests!"

These are contests open for a month, aimed at all those who find the myriad of puzzle contests a little intimidating.  You can complete the contest in your own time, although if you are feeling competitive you are more than welcome to treat this as a sprint against the clock.  The puzzles will be small, but not necessarily trivial to solve, and aim to get the less experienced solver more familiar with various puzzle styles within the framework of friendly competition.

Contest page:
Forum thread:

Wednesday, 16 May 2012

Update to FP155

So it turns out that a puzzle I wrote was broken.  Hrm, no huge deal there, I reckon that must have happened on this blog sometime before... except it sort of is.  The puzzle in question was submitted as part of a puzzle championship - and as far as I'm aware was actually "used" in said championship.  Which is obviously an issue for all those involved.  Well I assume it was an issue, I haven't actually heard any more on the matter.  At the very least, it is a cause of embarrassment for me.

Anyhow all I can do now is apologise, and belatedly offer this one instead.  It's been solved in my notebook, and in paint and I even had another look at the solution grid in the notebook.  If this one's broken I think I'll cry!
    #186 Arrow Sudoku – rated hard
All puzzles © Tom Collyer 2009-12.

Friday, 11 May 2012

Friday Puzzles #156

More sudoku this week I'm afraid.  I've had this puzzle lying around for a rainy day - but I think it's safe to say, dearest reader, that you'll not have seen many quite like this one. Enjoy!
    #188 Diagonal Sudoku – rated hard
All puzzles © Tom Collyer 2009-12.

Friday, 4 May 2012

Friday Puzzles #155

So I thought what I'd do for a while before sharing my puzzles this week is bore you a little with some copyright.  The puzzles on this blog are free for anyone to use and reproduce under the following conditions.  The first condition is that you do not use them for commercial purposes.  If you want to make my money from my puzzles then it is unacceptable that you do so without a (large) cut coming my way.  The second is that I am fully attributed, so that my work is fairly recognised as belonging to me.  This should at the very least feature my name and a link to this blog.  Should you wish to use my puzzles under any other terms, then you should get in touch and we can talk.

This is as stuffy as I am going to get with my puzzles.  I maintain this blog for the benefit of the community.  I would like the community to grow and expand, and if my puzzles can be used as part of this, then this makes me very happy indeed.  Although it would be nice, should you wish to use my puzzles elsewhere, to ask me first, I do not deem this to be necessary.  As long as you aren't being overtly offensive or abusive when using my work I will in fact be glad of the good advert whether I am conscious of this advert or not.

I wish more people shared my attitude.  With the advent of the internet, I believe a revolution in copyright is coming.

Anyhow, this week I have two Sudoku variants that I put together for the Polish national championships, which recently happened.  Two puzzles which I'd have been more than happy to have been published elsewhere, under the conditions outlined above, so that the wider community could enjoy them.  Turns out they are here first instead.  Enjoy!
    #186 Arrow Sudoku – rated hard
    #187 Irregular Sudoku – rated hard
All puzzles © Tom Collyer 2009-12.

Friday, 27 April 2012

Friday Puzzles #154

So I've apparently lost my faith in all of humanity, and most of my all my own self-esteem.  I wanted to spend ages knocking up a really nice yajilin puzzle, and instead this one simply fell out in 15 minutes. Enjoy.
    #185 Yajilin – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 20 April 2012

Friday Puzzles #153

Every now and again I worry that I might be using up all the possibilities for Masyu with twisted symmetry, but there always seems to be one more.  Not the most aesthetically pleasing, or indeed challenging puzzle, but one has to keep one's hand in.  Enjoy!
    #184 Masyu – rated easy
All puzzles © Tom Collyer 2009-12.

Friday, 13 April 2012

Friday Puzzles #152

More twodoku this week.  This one is probably undercooked in terms of difficulty - I'm fairly sure I can take out a couple of givens, but it will have to do.  There's certainly a little more interest provided with the irregular grid.  Enjoy!
    #183 Twodoku – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 6 April 2012

Friday Puzzles #151

Delayed, I'm afraid, until Sunday.  I was toying with the idea of putting out something old, or perhaps something that may or may not end up being used for the UKPA Open - but I think the safest bet is to simply wait until I can actually put out something new.  Sorry!

EDIT: better late than never.  Here's a Nurikabe which will hopefully have a couple of head scratching moments.  Enjoy!
    #182 Nurikabe – rated easy
All puzzles © Tom Collyer 2009-12.

Friday, 30 March 2012

Friday Puzzles #150

Well it's the last Friday of Lent, and writing as I have been - from waaay back in the past - this week's puzzle suddenly seems something of an anti-climax. The theme isn't quite perfect and it's not a hugely challenging puzzle either. Mind you, I've never been one for milestones in terms of week numbers, so perhaps I'll do something better for the three year thing coming up. Enjoy!

EDIT: No, nothing's broken with the puzzle this time round, but I have to raise two points.  First blogger have decided to suck harder than a Texan trying to retrieve a golfball stuck in a hosepipe and have apparently ballsed up the commenting "feature".  Ever since google decided to change its privacy policy, all sorts of shitty little bugs have been rearing their ugly heads with the service.  Even before that, they couldn't get something simple like putting time-stamps on the comments in the correct time zone.  I can only hope the reason for the current comment downtime is they are fixing this.

Anyhow, blogger may provide they provide a free service, but so do many others without causing me the need to rant.  And where better to rant than into the vast vacuums of tinternet.

Second point.  Lent doesn't end on Good Friday (thanks pub quiz at The Pilgrim) and so this leaves me in something of a pickle for next week.  I'll think of something, I'm sure.
    #181 Nurikabe – rated easy
All puzzles © Tom Collyer 2009-12.

Friday, 23 March 2012

UK Open Sudoku and Puzzle Tournament 28-29 April 2012

No, it's not a bonus Friday puzzle I'm afraid.  This is for the benefit of the 22.5% of the traffic this blog has attracted in its current incarnation, heralding as it does from the UK.

The wonderfully fabulous UKPA is having a two day puzzling event in Manchester at the end of April.  If you enjoy the puzzles on this blog, then you will love what's on offer at this event.

Even more, if you've ever trawled your way through one of my horrible long championship reports and thought that you'd like to have a go, then this will give you a good idea of what it's all about: getting together a good crowd of like-minded puzzling enthusiasts and together enjoying a quality set of puzzles.  You can look forward to puzzles from the following sources:
Anyhow, I'd thorough encourage people to get involved.  If you are thinking that it might not be for you, I can only say that it's definitely worth a try.  You never know, you might even surprise yourself!

More details, and registration information here:

Friday Puzzles #149

There's something visually very wrong with this Masyu puzzle, compared to my normal fare.  And I suppose a V counts as a 5, even if you rotate it to a C or an N.  Or that other thing.  Anyhow, fairly plain sailing, but watch your step.  Enjoy!
    #180 Masyu – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 16 March 2012

Friday Puzzles #148

The theme is running onwards, although perhaps a little more weakly this week.  There are lots of 4-boxes I suppose!  Still, I think this one is pretty cute, if you've not seen the tricks before.  Enjoy!
    #179 Ripple Effect – rated medium
All puzzles © Tom Collyer 2009-12.

Friday, 9 March 2012

Friday Puzzles #147

Three is the magic number, and although maybe this week's Heyawake puzzle might seem a little same-y to my dearest readers with a longer memory, I think finally perfecting the theme is worth the post.  Enjoy!
    #178 Heyawake – rated hard
All puzzles © Tom Collyer 2009-12.

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