Monday, 31 December 2012

Puzzle #152: International Borders

Happy New Years India

As you might have noticed, this set contains far more new genres than my first set. I just wanted to avoid repeats of previous genres as much as possible. So I went on a long look through websites, looking for genres that might work with some of the numbers. From Palmer Mebane comes the puzzle type International Borders. During his LMI test, Puzzle Zoo, was the first time I came across it. I solved both of these puzzles during competition. I was hoping this genre would lend itself for a single digit puzzle, as it was different from most puzzle types. I first tried the number 0, but didn't like anything that came out of it, so I changed to the number 1. I found a simple opening and some interesting steps with only using 1's. I had to give in a bit to get it unique though. This isn't the best puzzle in the set, but I think it's still enjoyable. I might try this another time with more numbers, because it was pretty fun to try and design one of these.
It's probably and easy/medium puzzle. It might just take a while to get used to the genre.

1 - International Borders

Colour some squares without circles black, so that the grid is split into 2 seperate orthogonally connected areas. Circles of the same colour should be part of the same area, different colours should belong to different areas. Grey circles can be part of either area. Numbers in the grid indicate how many of the four orthogonally adjacent cells have to be coloured black. All black cells should share a border with both areas.

Puzzle #151: Sandwich

Happy New Years Indonesia and China

I went on the hunt for some puzzle genres I had never done for this set. One of the places this regularly leads me is of course Naoki Inaba's site. There seem to have been a few changes to his site. You can now copy all Japanese characters and some of the puzzle types have English translations added to it from the Naoki-Projekt on Logic Masters Deutschland. When I saw this type, I figured it could be a good genre to use the number 2 on. It took a while to get it unique. The opening is a bit standard, but in the end it gets a bit trickier, but there was no better way to force it unique. The name of the genre comes from google translate. It translated the puzzle name as "Santoitchi" but suggested I might mean the Japanese for Sandwich. It might have an alternative meaning but I got persuaded to just name it Sandwich. I have no real clue why it would called this though and I guess I could just stick with Santoitchi, as many Japanese puzzle types keep their original Japanese name.
The puzzle is medium/hard difficulty. There's a logic path to the end, but for a new genre it might be a bit trickier. It might help to try some of Naoki's at first.

2 - Sandwich

Colour some cells black, so that the remaining area can be split up into triminoes. No two black cells can share an edge. Each trimino must contain a number. A number indicates how many black cells share an edge with that trimino.


Puzzle #150: Lighthouses

Happy New Years Japan, South Korea and the rest of Australia

I tried a whole bunch of puzzle variants for the number 3. Slitherlink, Corral, Tren and Minesweeper were a few of the puzzle types. As I already had enough Loop Puzzles and not really any placement puzzles, I tried to find a genre that might work. Lighthouses was one of these puzzle types. The puzzle isn't very special, but I think it turned out okay.
This is an easy puzzle, probably the easiest in the set. Shouldn't take people too much time.

3 - Lighthouses

Place a number of 1 cell ships in the grid, so that no two ships touch eachother, not even diagonally. There are a few lighthouses in the grid. The lighthouses can see horizontallyand vertically. The numbers indicate how many ships can be seen in all four directions. No ships can touch the lighthouses, not even diagonally. Squares with water can't contain any ships.

Puzzle #149: Bosnian Road

Happy New Years Australia.

This is one of the new types to my blog in this set. I hadn't made any of these puzzles before this one. Again my first choice of digit worked out. I had seen Prasanna Seshadri make some good use of the number 4 in one of his puzzles, so figured this number might work. Took a while to get it right though as the number didn't let itself be unique that easily. It's the number which has the most possible configurations in this genre. It took a while to get the end right, but I thought the opening was really solid, so I wasn't going to give up on the opening and eventually i found a nice way to get it unique.
It's easy/medium difficulty. The opening is fairly standard, but it has a few trickier steps in the middle. Just for the fun of it, count the length of the loop in the end. It's purely coincidental, but I thought it was funny none-the-less.

4 - Bosnian Road

Draw a single closed  one-cell wide loop, that doesn't touch itself, not even diagonally. The loop doesn't go through clue cells. The clues indicate how many of the 8 cells around it are used by the loop

Puzzle #148: Tapa; Make Room for Pentapa

Happy New Years Samoa and New Zealand. 

The number 5 again had to be a pentomino puzzle for me. Last year's comined it with Nurikabe, where this puzzle combines it with Tapa. Other variants like Pentapa and Tapa Pentapool didn't really lend itself well for all 5 clues, but the added region constraint for Pentapa made it easier. I think it worked out well in the end and fits in well with the 5 theme this way.
This puzzle is again medium/hard. There's 2 important steps in the design, although the genre is pretty restrictive, so there might be other ways to the solution.

Rules for Tapa

Follow normal Tapa rules. Additionally, the Tapa wall is made up of 11 of the 12 pentominos (as the P-pentomino breaks a Tapa rule). Each blackbordered region contains exactly one pentomino.

Puzzle #147: All Seeing Snake

This puzzle came about after the For-Smarts Anniversary contest on LMI, where it was one of the puzzle types. I figured the rules had enough constraints to make a unique digit puzzle possible. As I needed a few puzzles with higher digits, I opted to try a puzzle with all 6 digits, as any higher would probably be too difficult. Played a bit with the grid sizes to see what would work best. Eventually this puzzle popped out. When I noticed it would have to be a 67 cell snake to make it unique, I opted to add an empty cell marked with an X, so the length would be 66 cells, as I thought that would fit in nicely with the 6 theme of the puzzle.
The puzzle is of medium/hard difficulty. Make sure to remember to make the Snake the right length.

6 - All Seeing Snake

Draw in the grid a snake of 66 cells. The body of the snake cannot touch itself, not even
diagonally. Numbers indicate how many segments of the snake are “seen” from this cell, not
counting the cell itself. Snake always makes a turn in the cells with numbers. The head and
the tail are not given and are subjects to determine. Cells with X remain empty.

Puzzle #146: Maxi Loop

This is one of my favourite puzzles in the set. I hadn't before made any Maxi Loop puzzles with larger cages, but I figured it was worth a shot. I chose 7 cells in 10 cell cages for my first try. I thought this would be the highest percentage of cells to be part of the clue to keep the puzzles interesting. If this wouldn't work out I always had the option to go 6 out of 10 or 7 out of 11. But tmy first try with this worked out really nicely. the solve is logical, but still challenging and I managed to get all cages to a 7.
I think this puzzle is a medium/hard difficulty, so it will probably take a bit more effort to solve. As always with a bit more unfamiliar genre, people might have some more trouble.

7 - Maxi Loop

Rules for Maxi Loop

Puzzle #145: Regional Yajilin

The higher numbers are always a bit trickier to find genres for. Last year's Island puzzle was a rare spark of genius as a choice, in my opinion. This year it's a Regional Yajilin. I spend a while looking for a good opening for this genre with the number 8. A few options didn't really lead to any good puzzles, but I think this one really worked very well.
I'm really happy with how it turned out. It's probably a bit challenging, because people aren't as used to how the black squares can be placed in this genre.

8 - Regional Yajilin

Rules for Regional Yajilin

Click to enlarge

Puzzle #144: Thermo Sudoku

The 9 was one of the tougher numbers to get a good genre for. I experimented with a few other genres, but many didn't work out. Some others worked better with other numbers, and I used those instead. Eventually I settled on a Sudoku as that seemed to work well with the number 7 last year. I used two 9 clues and part of the thermometers together form two 9's, so I think I put enough of the number in it, to warrant it a place in this countdown.
I think the puzzle turned out well. Not too hard, but some nice steps in there none-the-less.

9 - Thermo Sudoku

Rules for Sudoku

In this Sudoku, along a thermometer digits are always increasing, starting from the circle.

Puzzle #143: Sum Skyscrapers

This year we're starting the countdown with an easier puzzle than last year. The Killer Sudoku then was probably the hardest in the set. This time it's another sum variant, except this time it's a Skyscraper. This puzzle was again the first one I made. It was just one I made quickly about a month back and figured I should give this thing another go. I thought I might get things done in time this time, but in the end a lot of postponing and doubt on the genres to use, made me still trying to construct puzzles the last days before New Year's. I guess I work better with an imminent deadline.
The puzzle is easy/medium difficulty. Hope you enjoy it.

10 - Sum Skyscrapers

Rules for Skyscrapers

This skyscraper uses the digit 1~6. The numbers outside indicate the sum of the visible digits.

Sunday, 30 December 2012

New Year's Countdown 2013

The end of the year always seems to be my least active period in posting puzzles. To make up for it there will be another puzzle countdown to New Year's. The concept will be the same. 11 puzzles between 12am CET December 31st and 12am CET January 1st 2013.
So if you have some time to pass till New Year's, check my blog during New Year's Eve. For everyone else, I hope they will be a good start to 2013.

Thursday, 6 December 2012

Puzzle #142: Killer Sudoku

I've been a bit busy with other things, so hadn't had that much time to write puzzles for my blog. So here's a nice Killer Sudoku to pass the time. I wrote this one a while back but I think it's a nice one. I like Killer Sudokus without any 2 cell cages and this cage pattern works really well for such a puzzle. I hope you enjoy it.

Rules for Sudoku

In this Sudoku the given numbers are replaced by dashed cages. The number in the cage indicate the sum of the digits within that cage. Digits can't repeat within a cage.

Click to enlarge

Thursday, 22 November 2012

Puzzle #141: Japanese Sums

This weekend is the Japanese Sums Contest on Logic Masters Deutschland. It will feature 14 different Japanese Sums puzzles, one standard and 13 variants. All puzzles will use a 1~6 digit subset, instead of the 1~9 digit set I prefer. the 1~6 digit subset is most likely chosen as this leaves for puzzles that can be solved far quicker as Japanese Sums puzzles tend to take relatively long to solve. My puzzle therefore will not be the best practise for this test as it uses digits 1~9 but it's fun to solve.
On an unrelated note, all puzzle sets from the 24 hour puzzle championship are available on the WPF-forum. So if you have nothing to, that should give you plenty of puzzles to solve.

[Edit: Misclued number fixed in column 8]

Rules for Japanese Sums

Rules: Japanese Sums

Place the digits 1-9 in some of the squares, so that no digit is repeated in any row or column. Sums on the outside indicate the sums of consecutive digits in that row or column. Each sum is seperated by at least one empty square.

Tuesday, 20 November 2012

Puzzle #140: Broken Sudoku

At first I had tried to find a subset of 10 different pentominoes to create two 5x5 squares, but I wasn't able to do it. I'm not sure if it is even possible. It wouldn't be the first time I've tried to do something which wasn't possible at all. I think though that repeated shapes make it a bit more interesting as that gives more options for the 2 puzzles. The puzzle isn't too hard, but you have to remember that shapes can be rotated and mirrored, so you can't be sure of the placement of some numbers as certain pieces have symmetry. For 5x5 Sudokus I think they're pretty nice this way.

Rules for Sudoku

Fit the 10 pentomino pieces in the two 5x5 grids without overlapping. Pieces can be mirrored and rotated. Then solve the resulting Jigsaw Sudokus.

Thursday, 15 November 2012

Puzzle #139: ABC Decoder

This weekend is the Word Show test on Logic Master India, written by Nikola Zivanovic. It features 12 different puzzle types which all involve words. It includes standard puzzles types like Scrabble and Word Search, but also common puzzle types featuring words, like Word Nurikabe, Full Tapa and Sigma Snake. there are a few examples of some types on my blog. There's a Full Tapa in my TVC XI practise set, a Snail's Nest in my European Championship set (although the actual one will probably be more like the one featured at this year's USPC) and a Word Nurikabe from last year's 24 Hour Puzzle Championship, which I haven't seen anywhere else.
Today's puzzle will be an ABC Decoder. It's a type I always really enjoy. Part of the reason is that Richard Stolk always makes really nice ones. These feature often in Breinbrekers. They always have some nice theme going on in the words. I've made a few of these puzzles before, one of them featured in my LMI Hybrids test. It was made a bit easier so it would be more suitable for a puzzle competition. This puzzle features all puzzle genres. It is most likely harder than the one that will feature on the test, but it will still be good practise on how to solve these types of puzzles.


Every letter is encoded with a different integer from 1~26. In the given set of Puzzle Genres all letters occur except the letter Q. The numbers behind the words indicate the sum of the value of each letter in each word. Determine the value of all letters.

Tuesday, 13 November 2012

13th 24 Hour Puzzle Championship

The 13th 24 Hour Puzzle Championship was held last weekend. Nikola Zivanovic was the winner, with a close margin over Florian Kirch in second place. Peter Hudak completed the podium finishing third. Full results can be seen here.
I think this set worked out better than last year's. The topscorer in my set was Florian Kirch with 845/1000 points and everyone solving scored at least 100 points.

Opposed to last year, I will release my entire set in a single post. Last year I was still trying to keep up one post a day, but I've let that go for a while now. The post will not contain any examples, but you can see examples of each genre in the instruction booklet. My set is the 12th set, so you'll have to scroll down a bit. The puzzles have their value listed and are valued at about 10 points per minute.

Puzzles can be found below.

Thursday, 8 November 2012

Puzzle #138: Pentopia

This seems to be one of the puzzle types I come back to regularly. I just like constructing them. People seem to generally like the type and it's hard to find any of them anywhere else. Last year there was a one on the World Puzzle Championships made by Zoltan Horvath. Another one will feature in this weekend's 24 Hour Puzzle Championhip made by Prasanna Seshadri. These puzzles both need all 12 pentominos to be used, which is something I tend to steer clear of. I think the highest I ever went to was 11. I'd probably could make puzzles of size 13x13 or 14x14, which use all pentominos. But then it still wouldn't be a rule that you'd have to.

Rules for Pentopia

Click to enlarge

Tuesday, 6 November 2012

Puzzle #137: Crossword

The instruction booklet for the 24 Hour Puzzle Championship is out. My puzzle set will be the second to last set that is solved. Some of my puzzle examples are worth solving in my opinion. I'd especially single out the Battleships Observer, Killer Sudoku and Complementary Hexa Sudoku examples.
This Crossword puzzle is the last puzzle I made that won't appear in the set. I am not very strong at creating logic Word puzzles. I am not totally sure how to approach them. The way I do it, is that I create a grid with words and then check if it solves uniquely in a logical way. I've seen similar layouts for Crossword puzzles like mine before and I always approach them in the same way. That's how I made sure this one solved logically. I'd love to hear from other puzzle makers how they general go about creating logic Word puzzles as that's something I'd like to get the hang of at some point.
This puzzle is challenging. I'd love to hear what people think of it though.


Place all but 3 of the given words in the grid, so that they can be read left to right or top to bottom. Every cell will contain one letter.



Click to enlarge

Thursday, 1 November 2012

Puzzle #136: Paint-by-Frame

A lot of puzzling done last weekend. Two hours at Logic master India with Fillomino Fillia 2 and four time ninety minute at the Halas League tournament. It was overall an average performance by me.
Fillomino Fillia got mostly stunted by me ignoring a single outside clue on the Skyscraper Fillomino. I also forgot to enter 2 answer keys, but that seems to happen more often lately. I need to get better organised with my puzzle sheets.
Halas League Tournament went pretty well. The worst for me was the classic/classic variant sudoku part, which was to be expected. It also had my only answer key typo, that i didn't correct. The less familiar variants went a lot better, although I probably shouldn't have attempted the Sudoku Ball last. The puzzle parts went pretty well. I hadn't looked at the point distribution for the first round and started the Sudokuros too late and missed out on some of the higher value puzzles that way. On the second part I got a bit unlucky on the highest value Sum Between/Doppelblock with a small calculation error and thus finishing a few seconds late. Overall the puzzle tests were maybe a bit Latin Square heavy for me, especially the highest valued puzzle types.

Now to the actual puzzle. I also made it for my 24 Hour Puzzle Championship set. This one came out too hard as well. I actual had testers wondering if the puzzle even had a solution. This puzzle type was my favourite new genre from the last WPC. I thought the logic works nicely. I wanted to use some different tricks than my first puzzle, which I made as practise for the WPC. But clearly in doing that, the puzzle became more challenging. I still think it worked out nicely and hope you enjoy it.

Paint some cells black. Numbers on the outside indicate the amount of cells that are framed by the other colour in that row or column. Framed cells do not need to be consecutive.



Tuesday, 30 October 2012

Puzzle #135: Turning Fences

From 9-11 November the 13th 24 Hour puzzle championship will be held in Budapest. As always the championship will feature fourteen 100 minute puzzle sets, of which each competitor has to solve 13 sets consecutively. This is because part of the competitors have provided a puzzle set and thus can't solve their own set. Competitors who haven't provided a set will be matched to a constructor and they will not solve that set. Just like last year, I have provided a set for the championship. Last year's set was a bit difficult and this year I think I have provided a more balanced set.
This puzzle is one of the puzzles I had written that didn't end up going into the set. It seemed like a good puzzle type to let go a 24 and 13 theme on as adjacent digits 2 apart provide a good opening. The puzzle still tested somewhat too hard than what I had hoped for and was replaced by another puzzle. I still think it worked out welland is nicely solvable.

Rules for Turning Fences

Thursday, 25 October 2012

Puzzle #134: Fillomino; Liar

This weekend is the Fillomino Filia 2 test on Logic Masters India. The test is written by Grant Fikes and Palmer Mebane. It's a repeat of last year's Fillomino Filia test and will feature 4 classic Fillomino puzzles, 2 variants from last year's test and 2 puzzles each of 6 new variants. There are preview puzzles posted of the different types on their blogs.
I like Fillomino puzzles. I haven't always liked them though. The first time I came across them I had a lot of trouble with them. It was because I then solved it purely by filling in numbers. Now I mostly go by dividing the grid along the grid lines, which makes it much easier for me to see everything.
I hadn't previously posted any fillomino puzzles. It was mostly because I couldn't get any of the variants to work nicely. For this test I figured I'd give it another go. I constructed a Liar Fillomino as that was the variant I suspect would cause me the most trouble in solving as the interaction was more tricky than in Slitherlink because of the bigger number set. This puzzle is tricky. There's a point after the opening where there's a tricky step to make progress. For overall difficulty it's leaning towards the hard puzzle in the test, which is rated at 16 points/minutes.
I made a new template for this puzzle type with dashed lines. You can still colour the cells in paint as the white in the dashed lines differs slightly from the background of the squares.

Rules for Fillomino

Follow regular Fillomino rules. Additionally, in each row and column exactly one of the clues is wrong.

Click to enlarge

Rules: Fillomino

Divide the grid into different regions along the gridlines. No two regions of the same size can touch eachother by a side. Numbers in the grid indicate that this cell is part of a region of that size. A region can contain more than one given number. There can be regions without any given numbers.

Tuesday, 23 October 2012

Puzzle #133: Magnets

I've taken a short break from blog posts since the World Puzzle Championships. But I figured the 40 WPC puzzles make up for that. This is mainly caused by me working on a 24 Hour Puzzle Championship set. Creating these sets always takes up more time for me than I expect. In the upcoming weeks I'll be posting some remnants from constructing that didn't end up going into the test.
Today I'll be posting some puzzles that I made for Akil Oyunlari Issue 78. This issue featured two Dominoes puzzles and two Magnets puzzle by my hand. The two Dominoes puzzles were the same variation I had made for the Zagreb Open. The two Magnets puzzles were both puzzles with missing information, like I've constructed before on puzzle picnic, here and here. I also sent some regular magnets puzzles to go along with them, but they weren't published. So I'm posting them here.
There's one medium difficulty 10x10 magnets puzzle and two very hard 12x12 puzzles. The 10x10 puzzle has one of those standard openings I really like to put in Magnets puzzles. It's pretty easy to find, if you understand how to work this part of Magnets logic. The two 12x12 puzzles were my attempt to introduce some trickier openings into Magnets puzzles that I haven't seen before. The first 12x12 puzzle is actually the second I made. It's an easier version of the opening in the second puzzle, because I basically knew the first one would never be published in Akil Oyunlari.. Both puzzles use multiple rows and columns to force the first placements. You have to really understand how different rows and columns can influence eachother to get started. Both openings are perfectly logically deducable, but you do need to work a bit more for it than usual.
I hope you all enjoy the puzzles and the challenge.

Ruels for Magnets

Medium Puzzle

Click to enlarge

Very Hard Puzzle 1

Click to enlarge

Very Hard Puzzle 2

Click to enlarge

Friday, 5 October 2012

World Puzzle Championship 2012: Round 12 Half Dominoes

This round contains a single puzzle for which we have 50 minutes to solve. This seems like a considerable time, but we'll see how it works out. It seems finishable.
The puzzle is a Samurai Half Dominoes, where the rows and columns are counted as a whole. So if it's on the same height but different 9x9 grids, they still cant repeat. It's an interesting variation and funnily enough it doesn't even mean you need a lot more clues than normal. Just as a note, the Half Dominoes are a seperate image as that was easier.

12 Half Dominoes:

Place the given Half Dominoes in each 3x3 square so that each of the five 9x9 grids contains each half domino once. No Half Domino can be repeated in any row, column or main diagonal, even if they are in seperate 9x9 grids. Numbers on the outside indicate the amount of dots in that complete row, column or diagonal. Arrows with numbers indicate the direction of possibly ambiguous clues.

Click to enlarge

World Puzzle Championship 2012: Round 11 Something Newish

The round name says it all. There's some new puzzles or variations. We have an hour to solve 9 puzzles. This leaves chances for bonuses.
My favourite are the Domino Arrows and Fishermen, although they both would be nicer by removing one of the clue types. I didn't do that in my puzzles though. I figured I'd stick as close to the instructions as possible.
The Domino Arrows puzzle is a challenging puzzle. This is partly caused by its size. The logic isn't overly difficult, but you have to understand some of the tricks. This can be hard as it's a new genre. The Fishermen puzzle isn't too hard. It's basically an Anglers puzzle, with size 2 fishermen. The third puzzle I made was a Rural Tourism. I mainly made that one to completely understand the rules. It has a complex rules set. But once you figure it out, the puzzle solves nicely, although a bit challenging.
There's one more puzzle to come later today. Enjoy.

Puzzles can be found below.

World Puzzle Championships 2012: Round 10 Anthology

This round seems to be a dedication to previous championships. There's no actual explanation given, but it seems to be the fairest guess. You can see a bit of development in the type of puzzles over the years. From more observation and word types to the now more common logic types. I'm not exactly sure on why certain types were chosen.Types like Yajilin and Corral can't be that specific to a championship. A few of the ones from championships I've been to are easier to understand. The round will last 90 minutes for 20 puzzles, which is a pretty high average per puzzle.
I've only made 3 puzzles because many of the puzzle types I either don't really find interesting to construct or too hard to construct. The first puzzle I made is a Hiroimono. It's nothing new and many people will have come across it a few times. I'd just never tried it and wondered how it's done. I haven't really figured out how to best make them and I don't think it's too hard. At least I learned a bit about some of the tricks of the genre with it though. The Jumping Crossword I wanted to try to make for a while but I never find my results at all interesting. I don't really think this one is anything special either. I'm not sure how to make them turn out great but that's a general problem with word puzzles for me. The last one is a Tetrascope. I like polyomino genres, so I figured I'd give it a try. It's not really hard but then again I don't really think they can be.

Puzzles can be found below.

World Puzzle Championship 2012: Round 9 Metropolis

This round features seven Skyscrapers puzzles. One standard and six variants. A few new variants and a few more common variants. I think this puzzle should be fun. I think I can do well in it.
This was my favourite round to design. That's why I designed an example of each variant. At first I was planning to do only 3, but I couldn't really choose which ones. So in the end I ended up making one of each. The Dubai puzzle is medium to hard. The normal way of thinking is changed a bit by the extra number. New York makes this even a little harder, because one cell remains empty. This increases the amount of possibilities for each clue. This puzzle is my favourite in the set. Toronto isn't that hard a puzzle. It's the most common variant in the bunch. The Sydney puzzle has very little clues and I think it worked out really nicely. Tokyo I thought would be hardest to design, but it actually went pretty well. The first try ended up correct and I think the puzzle is fun. Sao Paulo isn't too hard. I like how the idea works as it's different from other variants seen before.
Hope you enjoy them as much as I did making them.

Puzzles can be found below.

World Puzzle Championship 2012: Round 8 Assorted Puzzles

This round lasts one hour and features mostly new puzzle types. Most are small variations or hybrids on known puzzle types. It's hard to judge how this round will go. We will see in about an hour.
The puzzles I made an example of were Pipeline, which is a U-bähn variant, Russian Field, which is a simple division puzzle, Coded Tetramino, a tetramino division variant and Squares, a possibly annoying squares placement puzzle. I chose these ones, because I had some idea of what to put in these puzzles. Another possibly challenging one was Dominoes in the Water, but I had no real idea how this would look and thus how to construct an example.
The Pipeline puzzle is pretty simple once you get the basics. The Russian Field is relatively tricky as it features a silly trick. But the small size should compensate. The Coded Tetramino should be somewhat challenging. I employed one possible opening in the puzzle. Also the easiest to build in. The Squares puzzle is pretty easy. I am not that handy in constructing this type.
Have fun with them.

Puzzles can be found below.

World Puzzle Championship 2012: Round 7 Lines and Arrows

The first round this morning is based around, well, lines and arrows. Drawing loops, lines and placing and following arrows. It will bean hour long round with a considerable amount of puzzles. From the values of the puzzles, there don't seem to be any really hard puzzles. There's two higher scoring puzzles but other rounds have had far bigger values puzzles.
As practise puzzles I made an example of each of the types: one loop puzzle, one line puzzle, one arrow placing puzzle and one arrow following puzzle. For the Loop puzzle I chose one of the easy types: Looking for the Loop. It doesn't leave very much room for freedom as the clues are not very restricting. So to make it unique, you basically end up with an easy puzzle. For the Line puzzle I chose Pipes, which is basically an Anglers puzzle, except multiple fishermen can catch the same fish. It's not very challenging. I think they can become difficult in a larger size with higher numbers, just like with Anglers. The Arrow placement puzzle is Pointing at the Treasure. It's a twist on Marbles puzzles where you place marbles, so that each marble is pointed at by one arrow and each arrow points at one marble. Except now the Marbles are placed and you have to place the arrows. This is my favourite puzzle in this set of four. I really like how it worked out. Lastly there's an Arrow Maze puzzle, which is more often known as 1~36(or whatever the end number is). I think my puzzle is relatively tricky. I like the end result as it has very few given numbers and is far more path based than number based.
Hope this second day is as enjoyable as the first day.

Puzzles can be found below.

Thursday, 4 October 2012

World Puzzle Championship 2012: Round 5 Black and White

This is the last individual round of the day, which is 90 minute round. The round is based around binary determination. A cell is either coloured or empty, a cell is either black or white. There's a few common puzzle types, a few new ideas and a few small variants on common puzzle types. I'm not really sure how this round will go for me as there are many types where the contrustion of the puzzle can really make a difference.
I prepared 3 new types and 2 more common types as practise puzzles. The White Pentamino puzzle is nothing spectacular but I think it's a fun solve. The no mirroring rule is not technically necessary for my puzzle. It still has the standard somewhat innate difficulty pentomino puzzles generally have. The Paint-by variants worked out really nicely in my opinion. It helped me a lot in seeing how these types work. The Tapa and Corral aren't anything spectacular. They were being very stubborn in construction and in the end I decided to just go for something simple.
Hope they are enjoyable.

Puzzles can befound below.

World Puzzle Championship 2012: Round 4 Easy as ABC

Here we start with the round of the first day that I expect is best suited for me. I never used to consider myself particularly strong in Easy as ABC puzzles, but the longer I've been solving online, the more I see that years of Breinbrekers practise has made me much stronger than I thought. I guess that's understandable, considering the amount of exposure I've had. The same goes for Nikoli subscribers with Nikoli genres.
This round won't feature any standard Easy as ABC puzzles though. There will be three Easy as ABC Crosswords, three Easy as ABC Snakes and three Hexagonal Easy as ABC puzzles in three different styles.
I will have an example of each of the three types. The Crossword is not difficult but pretty fun. The Snake I find the trickiest of the three genres and had some trouble constructing. The Hexagonal puzzle is my favourite of the three. Hexagonal Easy as ABC's always have far fewer clues than you'd expect. This is caused because the outside rows contain most the letters and thus there are far less solutions than a normal grid. I think these three puzzles should be fun.

Puzzles can be found below.

World Puzzle Championship 2012: Round 3 Twisted Puzzles

The third round of the WPC feature a number of classic puzzle type, with a slight twist. This slight twist usually means one of the main rules of the genre is broken and can't be applied while solving till you've fixed the twist. The twists in the puzzles not featured in this post are are an Easy as ABC clue in a Skyscraper puzzle, extra numbers in a Domino puzzle, empty cells in Kakuro and Arrows puzzles, 2 touching ships in a Battleships puzzle and an incorrect clue in a Four Winds puzzle.
I opted to design a Worms, Star Battle, Ariadne's Thread, Tents and Trees and Magnets variant. These were chosen for different reasons. Worms and Ariadne's thread I had never made myself and wanted to see how they are constructed and what the impact of the extra rule was. Star Battle I saw as the most dangerous twist to make a mistake in and construction clearly showed I was right as my first 2 attempts were broken as I had messed up with the twist somewhere. The Tents and Trees isn't so much different, but it was important to get one automatic solving technique out. the Magnets was just because I like designing Magnets and that was all for my own constructing pleasure.
I hope they are enjoyable, I surely enjoyed constructing them.

Puzzles can be found below.

World Puzzle Championship 2012: Round 2 Blackjack

The second round we are facing consists of twenty-one puzzles around a twenty-one theme as it is the twenty-first World Puzzle Championship. This is one of the larger mixed rounds, lasting 2 hours, which generally means far too many puzzles for the amount of time. So, a lot of options to choose from and hopefully make the right choices in which puzzles to start with, getting all the big pointers done in the middle and finishing on some quick low pointers to get those last extra points in and not end up leaving 25 points out by just running 30 seconds short on solving the puzzle. Usually my timing and puzzle choices are pretty good. This was shown best at the 2010 WSC, where I managed to put the last digit in exactly when the timer ran out. I was sitting near the spectators, who could see me solving and got a congratulatory pat on the back for finishing so nicely within the time limit.
This post will feature five puzzles from the twenty-one genres featured in this round.

Puzzles can be found below.

World Puzzle Championship 2012: Round 1 Domino Hunt

Good morning everyone. Here is the first "live" post from the WPC. The first round of the WPC will feature eight Domino puzzles. Except in the puzzles some of the numbers are missing. You'll have to restore them and fix the puzzle. It doesn't make a whole lot difference in the solving process, except that you have to watch out that you don't think a domino has only one place to go.
At the release of this post all WPC-participants should be bent over a booklet solving these puzzles if everything runs smoothly. This post contains only a single puzzle for you to solve. Enjoy!


A complete 0-6 set of dominoes has been placed in the grid. Then all the borders were removed. accidentally also some of the numbers were removed. Restore the numbers and the borders of the dominoes.

Monday, 1 October 2012

World Puzzle Championship 2012: Live Puzzle Release

I will be traveling with many others to Croatia today for the World Sudoku and World Puzzle Championships in Kraljevica. I will be aiming to repeat last year's performance by qualifying for the playoffs in the WPC and finishing on the first page of the WSC.
Last year this meant a hiatus of puzzles on my blog. This year this means the opposite. I wrote a big set of practise puzzles for the WPC for my Dutch compatriots this year. I will be sharing these puzzles on my blog during the championship. The puzzles will be posted while the WPC is going on. All puzzles will be posted "live" on my site. This means that every set of puzzles from a particular round will be posted at the time the round begins at the championship, so you can solve the same types of puzzles at the same time as the WPC competitors. Each puzzle in a round will be accompanied with the number it has in the round. If you would like to see an example of a puzzle before attempting it, you can easily check it in the instruction booklet.
Over Thursday and Friday everyone can thus get a taste of the puzzle types featured at the World Puzzle Championships. There will be 40 puzzles released from the 11 individual rounds at the WPC. Hope you all will enjoy them.

Thursday, 27 September 2012

Puzzle #132: Complimentary Hexa Sudoku

Before the Sudoku craze Hexa number place was my favourite variant. I like how it didn't have all numbers in every row and the 3 direction configuration led to some fun interactions. I haven't really seen many of these in a while though as most people have gotten to writing Sudoku variations in standard grids. I recently tried to write some again and this is one of the results.
I combined this puzzle with a variant I saw while test solving the Hungarian Sudoku Championship. Those were my favourite sudoku puzzles I tested. I thought it worked well together in a Honeycomb grid.


Place the digits 1~9 in every cell, so that no digit is repeated in any row in any of the three directions. When a dot is given between three cells, it means that two of the digits add to the third digit. Not all dots are given.

Click to enlarge

Tuesday, 25 September 2012

Puzzle #131: Masyu: Not Alone and No Touch

The reason there are two puzzles today is because I started designing the Not Alone Masyu and noticed that the same placement actually also makes a nice opening for a No Touch Masyu. So after completing the Not Alone Masyu I also used the opening to make a No Touch Masyu.
The Not Alone variation is based on the Not Alone genre. It uses similar logic as the alternating Masyu variation, where the loop has to alternate between black and white circles. In this type the loop isn't allowed to alternate between white and black circles. In other words, every circle is preceded or followed by at least one circle of the same colour. I think it works nicely in this puzzle and decreases the amount of circles necessary.
The No Touch variant was seen first on Palmer Mebane's blog. It has seen some appearance in other people's blogs and the Indian Puzzle Championship as well. It was mere coincidence that I spotted that the opening worked just as nicely for this variant. I couldn't just let it go and worked with the same opening to create a second puzzle. I think it worked out well.

Rules for Masyu

Not Alone Masyu:
Follow regular Masyu rules. Additionally the loop may never alternate between black and white circles. In other words, every circle is preceded or followed by at least one circle of the same colour.

No Touch Masyu:
Follow regular Masyu rules. Additionally, no two unused squares may share a border.

Saturday, 22 September 2012

Hungarian Puzzle Championship: Doppelblock

The last set of puzzles I provided to the Hungarian Puzzle Championship were four Doppelblock puzzles. They featured in the non-classics round.
I've recently started to construct these puzzles and having fun with them. It's one of the few suggestions I had for the non-classics round and this one fitted in best. As this is an uncommon genre I didn't have to put much difficult in but could keep the puzzles fairly standard.
The first puzzle is a 6x6 puzzle based around larger numbers. The placement of the black squares can be derived without placing any numbers. Nothing challenging about this puzzle.
The second puzzle is a 6x6 puzzle built around the number 0. The black square placement is a bit trickier than the first puzzle. Overall it shouldn't cause much problems though.
The third puzzle is a 7x7 puzzle. The increased size of the puzzle is mainly what makes the puzzle trickier. I like how the puzzle worked out. Especially the 2 column finish was really nice.
The last puzzle is an 8x8 puzzle. The clues are split between odd and even clues for rows and columns. The puzzle has a very narrow opening, which makes the solve tricky. I really think though that the logic and layout worked out very well.
Overall I think these four puzzles showed very well what's possible with this genre. So far I have limited to 8x8 puzzles, but I'm going to try to extend it to 9x9 and bigger as well. But I'm not sure if its possible to create them without giving clues in the grid as well.

Rules for Doppelblock

Puzzles can be found below.

Thursday, 20 September 2012

Hungarian Puzzle Championship: Star Battle

Today will feature 4 Star Battle puzzles I contributed to the Hungarian Puzzle Championship. The Star Battle puzzles also featured in the Classics round.
Designing Star Battle puzzles in the 10 minute time limit is easier than Kakuro puzzles, because the average solving time for a Star Battle puzzle is much lower than a Kakuro puzzle. So puzzles don't have to be overly easy to have a solving time of 1-2 minutes for the best solvers.
For the two easier puzzles I wanted two different types of openings.Most Star Battle puzzles employ one of these two openings. The first one is the easiest of the two. It revolves around a single star that can be directly placed. From there the puzzle quickly resolves.
The second puzzle has a different standard opening, although maybe in a not so standard place. I do think it stands out among the other areas. This puzzle resolves a bit slower than the first puzzle as it has a few key points in the middle of the solve to make progress.
The third puzzle has the type of opening I like to do. At first sight, neither of the standard openings seem to apply but with a simple deduction one appears. It's a bit harder in this puzzle to keep making progress as there are a few key deductions that have to be made in order.
The fourth puzzle has a more atypical opening. I've used a similar one before in my other Star Battle puzzles. The opening doesn't stand out instantly but it should be clear how it works none-the-less. I think this puzzle is the hardest because it employs the most obscure opening and the way to make progress afterwards is hardest among the four puzzles.
I've added a fifth puzzle that wasn't used in the championship, but I constructed for it though. It was actually the first puzzle I constructed, using three cages that spell out HUN, that was meant as the hardest puzzle of the four. But after making three others I found it was too hard to be included in a set of three other puzzles, I made an extra one that is a bit easier to solve. To solve this one you need to see how different cages work together far more than the other puzzles. This makes the solve far trickier than any of the other four puzzles.

Rules for Star Battle

Puzzles can be found below.

Rules: Star Battle

Place 2 stars in every row, column and black bordered area. The stars can't touch eachother, not even diagonally.

The example uses only 1 star.

Tuesday, 18 September 2012

Hungarian Puzzle Championship: Kakuro

At the request of Zoltan Horvath I contributed some puzzles to the Hungarian Puzzle Championship held this weekend. I will post all puzzles this week. The general requirements were 2-4 puzzles for a solving time of 10-15 minutes. The test consisted of a classics and non-clasics round. Today we start with Kakuro, which was featured in the classics round.
I've always liked writing Kakuro puzzles, but I generally tend to write difficult puzzles. So my first goal was to write 2 easy puzzles with all basic deductions, with openings in multiple places. It took me a while to get that done actually as I automatically tend to put in harder things without thinking about it. I made 2 easy puzzles which turned out well. In hindsight it would have probably been better to make them a bit smaller to make the solving time less. But I figured they'd both fall between 1-3 minutes in solving time for the fastest solvers. The first one was just a simple circular pattern you can almost go in on big haul around the track. The second puzzle was a bit more open pattern, with a few more places where the puzzle can open up. I had the first one tested to see if this was actually enough on the easy path, as I find it hard to actually judge difficulty of Kakuros and it seemed to be okay.
The third puzzle I wrote had a few harder deductions, but the main thing that made it harder is that is has a single opening from which you have to work through the puzzle. It turned out to really not be anything special. It was one of those puzzles I have written many of.
The fourth puzzle I wrote is actually one of my favourite Kakuros I have written ever. It was built around a pattern which employed eight interlocked 8-cell sums. I made them all a different value. Because of the many  larger sums it uses certain techniques which you don't normally encounter much in Kakuro puzzles. It has some similarities in layout and solving to another puzzle I have written before. I think this one turned out better.
During testing of course it again turned out that my judging of Kakuro difficulty was far off the norm and instead of four puzzles, only two of the puzzles were used. Only the second and third puzzle ended up in the championship but I'm still posting all four puzzles in this post.

Rules for Kakuro

Puzzles can be found below

Rules: Kakuro

Fill every cell with a digit from 1-9. Numbers above a diagonal line indicate the sum of the digits in the consecutive white cells immediately to its right. Numbers below a diagonal line indicate the sum of the digits in the consecutive white cells immediately below it. No digit can be repeated within a single sum.

Thursday, 13 September 2012

Double Trouble #8: Skyscrapers and Haido

Haido is a puzzle type that I've recently come across a few times again. It showed up in a recent Skyscrapers contest hosted on Logic Masters Deutschland and the latest Akil Oyunlari magazine. All puzzles I've recently solved were really nice. So I tried making a few and found them more interesting to make than I at first thought they would be. When I saw the results, I thought they all look exactly like normal Skyscrapers puzzles. But they never solve uniquely as a skyscrapers puzzle. Usually they don't even have a valid solution.
So this led me to try to design one that worked as both. I found it hard to find an opening that worked nicely for both. so I cheated a bit with introducing a 6 clue for the skyscrapers puzzle, which is meaningless in the Haido puzzle. I like how they both turned out, although they are challenging.

Rules for Skyscrapers

Rules for Haido

Firstly this puzzle can be solved as a regular Skyscrapers puzzle. This is a hard puzzle.

Secondly it can be solved as a Haido puzzle. It is harder than the skyscrapers puzzle. I haven't solved any that are this difficult.

Rules: Haido

Haido is a genre based on the Skyscrapers genre.

Place the digits in the given range once in every row and column. The digits represent skyscrapers of that height. The clues on the outside indicate that the building of this height is visible in that row or column from that side. Larger skyscrapers block the view of smaller ones.

The example uses the digits 1-4.

Tuesday, 11 September 2012

Puzzle #130: Pentomino Areas

Pentomino puzzles I have slowly grown into. When I first started puzzling, I always had a lot of trouble solving them. In my early Breinbrekers issues, pentomino were the ones that were most often left unsolved. I prefer the placement type pentomino puzzles over the packing type. I've never been very good at packing problems. I've gotten more proficient at pentomino puzzles over time and now usually enjoy them.
Pentomino puzzles were the first type I regularly contributed to Breinbrekers, where I would write 18x18 Battleship-like puzzles, which used all Pentominos twice. I haven't written them in a while though. They take a while to get unique and solvable.
This pentomino type will appear in the upcoming LMI-test Borders & Beyond written by Prasanna Seshadri, which I was a test solver for. The type can sometimes get me stuck badly. The last time that happened was at the Dutch Puzzle Championship in '06, when it was featured in the semifinals and I couldn't get it done and ended up guessing my way through. Luckily I could catch up on the second puzzle and still qualify for the finals then.
This puzzle has a feature I like to use in puzzle types as all areas are the same size, which isn't common in this puzzle type. I have done the same in LITS as well, although there it was only on an 7x7 and 8x8 size.


Place all 12 pentominos once in the grid so they don't touch eachother, not even diagonally. Each blackbordered area contains one pentomino.

Click to enlarge

Thursday, 6 September 2012

Puzzle #129: Contact

I've given this genre another go. I think the 1 through 7 theme worked out pretty nicely. The opening of the puzzle is easy, but it gets a bit harder towards the end.
For everyone who's been trying to get to this post yesterday from other blogs, I'm sorry. I accidentally forgot to add the scheduled time.

Rules for Contact

Tuesday, 4 September 2012

Puzzle #128: Expanded Sudoku

I have played around with this idea a bit already before. When it popped up in the US Sudoku Qualifiers under the name Sudoku stairscases, I figured I'd give it another go. I prefer Expanded Sudoku as Sudoku Staircases really only work for one layout. I made the first ones back in early 2010. There'd been other Sudokus with gaps in rows, but I hadn't seen them with the standard 3x3 blocks. My first puzzles are puzzle #1695 and #1703 on PuzzlePicnic. Later on I tried to make them with irregular cages too, namely puzzle #2584 and #2607. The logic in them isn't any harder than any normal Sudoku, but I still think the increased size adds a bit of an extra challenge.
This puzzle isn't any harder than the other puzzle. I like how it looks though. This puzzle has one more challenging step that stayed in the puzzle while maintaining uniqueness.

Rules for Sudoku

In this puzzle the rows and columns continue over empty space.

Thursday, 30 August 2012

Puzzle #127: Easy as ABC; Regional

With this puzzle it is back to old school puzzling for me. Easy as ABC puzzles are one of the first puzzle types I solved. They used to appear as an extra puzzle in Logiquiz magazine. These were my real introduction to logic puzzling. This was before I started buying Breinbrekers. They appeared under the name Letterraam, which is a name for an old tool to help kids learn to read in Dutch. Without these puzzles I would have probably never bought Breinbrekers.
These puzzles uses two common variations on the genre. Firstly they don't use the standard "first seen" clues, but indicate the position of the letter when looking from that side. So A3 means that A is the third letter when looking from that side. This variation makes constructing larger grids much easier as large grids tend to get uniqueness problems in the centre, where your clues don't have any effect. Secondly they have regions that function just like a Sudoku. This helps reduce the number of clues necessary to make it unique.

Rules for Easy as ABC

Fill the letters A~E (A~G in the larger puzzle) once in every row, column and black bordered region. Otherwise follow Easy as ABC rules.

Medium Puzzle


Hard Puzzle

Click to enlarge

Tuesday, 28 August 2012

Puzzle #126: Tapa; Mastermind: Tapa/Knapp Daneben Tapa

At first I was trying to make a Knapp Daneben Tapa that looks exactly like a normal Tapa. That wasn't as easy as I hoped it would be. So I changed my approach and added the Mastermind component to it. This made it far easier to construct. The puzzle itself is pretty tough though.

Rules for Tapa

Tapa Mastermind:
The gray numbers between corresponding rows represent Mastermind clues. The numbers indicate how many squares in the same position are coloured in both grids.

Knapp Daneben Tapa:
Follow regular Tapa rules. Additionally all given digits are wrong. They are all either 1 higher or 1 lower than the given value. This means a 1 can possibly turn into a 0.

Click to enlarge

Thursday, 23 August 2012

Puzzle #125: Ripple Effect

Here's another Ripple Effect puzzle. It's been a while since I posted one. this is mostly caused by the fact that I've been writing Ripple Effect puzzles for Breinbrekers as well. It's not always easy to find good openings for clueless grids. It also helps to not make any errors. The construction took a while as I had made a mistake very early on and didn't notice after finishing the puzzle on my fifth try. Took me another four attempts to fix that mistake correctly. But in the end I think the puzzle worked out well. I have used a similar opening before. It's moderately hard, as most my Ripple Effect puzzles are.

Rules for Ripple Effect

Tuesday, 21 August 2012

Puzzle #124: Doppelblock

I'm back again to posting. Hopefully for a while. The Olympics were the main contributing factor to me not posting. I spend most my free time watching the Olympics. I didn't really find the time to create puzzles then.

Today we have three Doppelblock puzzles. It's originally from Naoki Inaba, I'm going with the German name from crocopuzzle. Simple name, but it sounds nice. Serkan Yurekli gave it an English name in Smashed Sums, but I didn't particularly like that name.
When I first saw this genre on crocopuzzle, I liked it. Although crocopuzzle regularly has this small minimal puzzle that is a bit annoying to solve as it's too had to discover the logical path. The larger ones are always nicer, but tend to have givens in the middle. This makes them a bit less elegant to me. It feels a bit similar as givens in skyscraper grids.
I think the puzzles worked out well. Nothing too difficult, but something to keep you busy for a little while. This puzzle type will also appear in the UK Puzzle Championship over the upcoming weekend, so it will be nice practise in this genre for those competing. It was merely a coincidence though. I had made these puzzles before the instruction booklet came out.

Rules for Doppelblock

Easy Puzzle

Medium Puzzle

Hard Puzzle

Rules: Doppelblock

This genre was developed by Naoki Inaba,

Colour 2 squares black in every row and column. Fill the remaining white squares with the digits 1~N, so that each digit appears once in every row and column. N equals the size of the grid minus 2 (e.g. for the example N = 3). The numbers on the outside indicate the sum of the digits in between the 2 black squares in that row or column.

Tuesday, 24 July 2012

Puzzle #123: Parquet

Here's again one of Naoki Inaba's genres. It has some similarities to the Windows genre, which featured in the WPC, which can also be found on Naoki Inaba's website. It's known as conect on his website, but I don´t find that a very nice name. I changed it to Parquet as the grids reminded me of the Parquet Sudokus.
The puzzle worked out really nicely in my opinion, utilising all rules as well as possible on a 10x10 grid.

Rules for Parquet

Rules: Parquet

This genre was developed by Naoki Inaba.

Colour one of two regions in every blackbordered 2x2 area to form a single contiguous shape. This shape doesn't have any 2x2 coloured sections anywhere. Also this shape doesn't form any loops anywhere.

Thursday, 19 July 2012

LMI Practise : Logirace

A recent comment on my blog mentioned how Loop genres feature prominently on my blog. It's somewhat true as I am better at finding interesting things to do with loop genres. This weekend happens to be a puzzle test on Logic Master India named Logirace. This test features nothing but loop genres. Half of them are Nikoli Loop genres(Corral, Country Road, Masyu, Slitherlink and Yajilin), 3 less familiar genres (Dutch Loop, Tapa Loop and Dotted Loop) and 2 that are new to me(Border Loop and Comet). I figured I'd try to make a few examples of the less familiar ones. Some puzzles worked out better than others. I didn't like working with some of the genres so much. Hard to get them unique and nice. Especially the Comet and Dotted Loop have issues of there being a unique solution a lot in construction. But I think each puzzle will help a bit in preparing for the test, if that's what you're interested in. Otherwise just solve them for fun. It's what puzzling is really about.

You can find the puzzle below. If you want to see smaller examples, check the instruction booklet.

Tuesday, 10 July 2012

Puzzle #122: Shakashaka

I haven't seen how the Nikoli puzzles of this genre tend to look like, but I expect mine are a bit different. I prefer to keep the amount of clues as low as possible and make the open areas resolve themselves. I figure my puzzles tend to be on the harder side because of that. I like how it turned out. I was planning on doing a 1-2 antisymmetric clue pattern, except the 3 forced itself and I liked how the puzzle went till that point. So this is how it ended up.

Rules for Shakashaka