Puzzle #193: Greater Wall

Two weeks ago was the Dutch round of the WPF Grand Prix 2016. I wrote all the puzzles for this set, both the casual and competitive section. The sets can be found on the following links: Casual and Competitive. Not all puzzles I had written were used as the set, either because they were not needed or were too difficult. This post contains the puzzles of one type that weren't used.

This post will contain four Greater Wall puzzles. It's my own genre and I still had a lot to play with in this genre as it's still fairly new. That's why I wanted to include it. The first three were the original puzzles I had written, but in the end they were replaced with three other easier puzzles. The fourth was not used as a replacement. The puzzles used in the test all had more straightforward openings. In these puzzles, the openings are a little more complicated. They still given enough information for an easy start, but it needs a bit more effort to get through it completely. Puzzle 2 and 4 use the same opening clue, but the first one is harder to get through.

Rules for Greater Wall

Colour some cells to create a single orthogonally connected wall. The wall can't cover any 2x2 area anywhere. Where given, clues outside indicate all connected blocks of shaded cells in that row or column, in the correct order. Relations between two placeholders apply to the lengths of the corresponding blocks.

Puzzle #1

 

Click to enlarge

 

Puzzle #2

 

Click to enlarge

 

Puzzle #3

 

Click to enlarge

 

Puzzle #4

 

Click to enlarge



Puzzle #192: Magnets

Two weeks ago was the Dutch round of the WPF Grand Prix 2016. I wrote all the puzzles for this set, both the casual and competitive section. The sets can be found on the following links: Casual and Competitive. Not all puzzles I had written were used as the set, either because they were not needed or were too difficult. This post contains the puzzles of one type that weren't used.

This post contains four Magnets puzzles. One of them I never submitted, as I thought it would be too hard, but it's still a nice solve. I enjoy solving magnets puzzles, but the puzzles I write tend to turn out pretty hard. I've come to write more magnets puzzles these days that don't have all clues given. I find them more interesting that way. It leaves all clues being useful till the end. The first puzzle is an easier small puzzle. It uses some standard techniques to open up the puzzle. The second puzzle is a bit harder. It uses the interaction between different rows and columns much more. The third puzzle was a similar layout as the first. It works on some standard logic to start off as well. The fourth puzzle is also a larger version of the second puzzle. One clue per row and column usually seems to work the nicest for me.

Rules for Magnets

Puzzle #1

 

Click to enlarge

 

Puzzle #2

 

Click to enlarge

 

Puzzle #3

 

Click to enlarge

 

Puzzle #4

 

Click to enlarge



Puzzle #191: Word Packs

Two weeks ago was the Dutch round of the WPF Grand Prix 2016. I wrote all the puzzles for this set, both the casual and competitive section. The sets can be found on the following links: Casual and Competitive. Not all puzzles I had written were used as the set, either because they were not needed or were too difficult. This post contains the puzzles of one type that weren't used.

This post will contain two Word Packs puzzles. This was the only type to be included in the Casual section. It's a type that I've seen in Breinbrekers before, but not really anywhere else as far as I can remember. I thought it would fit in well in the casual round. It was judged to be too varying in solving times to get an accurate rating for it. As the Casual section wasn't finished by anyone, it wasn't really missed. These puzzles generally work in a similar way. It's all a matter of understanding the logic involved. Usually the words are themed, to make it a bit more interesting. The themes I used for these two puzzles were Animals and Countries.

Rules for Word Packs

Place the given words in the grid, so that each rectangle contains exactly one word. Words in rectangles that touch each other can't contain the same letter.

Puzzle #1

 

Click to enlarge

 

Puzzle #2

 

Click to enlarge



Puzzle #190: Tapa

Two weeks ago was the Dutch round of the WPF Grand Prix 2016. I wrote all the puzzles for this set, both the casual and competitive section. The sets can be found on the following links: Casual and Competitive. Not all puzzles I had written were used as the set, either because they were not needed or were too difficult. This post contains the puzzles of one type that weren't used.

This post will contain three Tapa puzzles. These puzzles were written in case a simpler genre needed to be added. Neither of them is particularly difficult, but they still are pretty nice. I thought the first puzzle had an interesting kind of symmetry. The solve is not too hard. The second puzzle worked out okay. I added more clues than I normally would. There's a few places to start and they al come together in the end. The last puzzle is a nice 10 clue puzzle. It's a low clue count for a 10 by 10 puzzle, especially with a symmetric clue distribution. The solve worked out pretty well.

Rules for Tapa

Puzzle #1

 

 

Puzzle #2

 

 

Puzzle #3

 

 

 

  

Puzzle #189: Turning Fences

Two weeks ago was the Dutch round of the WPF Grand Prix 2016. I wrote all the puzzles for this set, both the casual and competitive section. The sets can be found on the following links: Casual and Competitive. Not all puzzles I had written were used as the set, either because they were not needed or were too difficult. This post contains the puzzles of one type that weren't used.

This post will contain Turning Fences puzzles. I enjoy this genre. The puzzles always are fun to write for me. I've done a lot of these puzzles and have figured out pretty well how the genre works. I wrote a tutorial for this genre a while back, which might be useful when doing these puzzles. I changed the layout a bit as I thought this was easier for notation than using the Slitherlink layout.
The puzzles aren't the hardest I've written, but I thought that would work better for the GP. The first puzzle is pretty straightforward. It only has even clues. The second puzzle has a simple opening, which leads to a harder finish. I wanted to leave the middle blank. To guide the loop through the clueless middle, I needed to make the end a bit harder to get it unique. The third puzzle is a bit more even in difficulty. It has one important step in the middle of the solve, but the rest should be smooth.

Rules for Turning Fences

 

Puzzle #1

 

 

Puzzle #2

 

 

Puzzle #3

 

 

 

 



Daily League #68: Inside Sudoku and Outside Sudoku

This is the second twin Sudoku. This time it's a combination of Inside and Outside Sudoku. They're pretty similar types, but the solve is still different.

Inside Sudoku first appeared on the US Sudoku Qualification. I thought the idea worked pretty well. I don't remember seeing it anywhere after that. I turned the idea in a Frame Sudoku, which has been repeated numerously, mostly by Richard Stolk.
The construction of the combination took a bit of work. Setting up the opening was pretty easy, but after that it gets a lot trickier. It's hard to pick the right digits that help both puzzles along. I liked the opening and found some points that nicely helped both puzzles along. It was hard to find a way to get both puzzles unique. There were a few situations that wouldn't resolve uniquely and I took a while to figure out how to avoid those.
I think both puzzles turned out nicely. The Outside Sudoku is the easier of the two. You get a lot of simple digits from the opening, while the Inside Sudoku's opening is more of a struggle. Enjoy.

Rules for Sudoku

Inside Sudoku: In this Sudoku digits on the outside indicate that these digits must appear in the 2nd, 3rd or 4th cell in that row or column when looking from that side.

Outside Sudoku: In this Sudoku digits on the outside indicate that these digits must appear in the first three cells in that row or column, when looking from that side.

Click to enlarge

Daily League #67: Edge Sums Sudoku and Frame Sudoku

Possibly this month will feature five Double Trouble Sudokus. I have written two so far, but I don't know if I will be able to write three others in combinations I haven't seen before. But I'm at least going to give it a try.

This week the puzzle can be solved both as an Edge Sums Sudoku and as a Frame Sudoku. I have used them together in a puzzle, but now they're separate puzzles. I tried for a while to get both puzzles to be solvable without any givens. I only had a limited range of sums to work with, which caused some issue. Edge Sums was the hardest to get unique in this combination as Frame Sudoku gives you the option of creating a useful implied sum. Eventually I compromised by putting two givens in the middle. The Edge Sums puzzle is the easier of the two in this set.

Rules for Sudoku

Edge Sums Sudoku:
In this Sudoku numbers on the outside indicate the sum of the first two digits in that row or column, when looking from that side.

Frame Sudoku:
In this Sudoku numbers on the outside indicate the sum of the first three digits in that row or column, when looking from that side.

Click to enlarge

16th 24-Hour Puzzle Championship

The 16th 24-Hour Puzzle Championship was held in Budapest this weekend. As always the championship featured 14 puzzle sets to be solved over 24 hours, with each round lasting 100 minutes, with only 10 or 20 minute breaks in between. Neil Zussman was this year's winner with a slim 10 point lead over Robert Vollmert in second place and a 23 point lead over Michael Mosshammer in third place. Full results can be found here.

All puzzles of this championship (except round 11) can be found here. If you need an example of any of the puzzles, you can find the instruction booklets here.

I provided a set again this year. It was the 8th set to be solved between 11pm and 12:40am. The set contained 24 puzzles. It featured 12 genres, with one puzzle being a standard and one puzzle being a variant. I was originally going to include only 6 genres and two standard puzzles and two variants. I found it hard to decide on the genres to provide enough variation. I tried to keep all variations different per genre, to add to the variation in the round. I think it ended up being a good mix.
Robert Vollmert was the top scorer of the round with 810 points.

Puzzles can be found below

Daily League #66: Round Off Sudoku

This is the last puzzle that was originally written for the Polish Sudoku Championships.

The last puzzle is a Round Off Sudoku. I've solved a number of them, but had never written them. Most of these puzzles were written by Richard. I wanted to give a nice pattern with relatively few cages. I thought the problem would be getting it unique, but at the start I ran into a lot of situations where there was no solution left. When I finally figured out where I was messing it up, it was still a struggle to get it right. I had a few puzzles that turned out a bit too hard, where I didn't think it would fit into a puzzle competition. The opening created a few sticking points I had to avoid, which would easily lead to uniqueness issues that I had no way to fix. This was the puzzle that came out in the end. It shouldn't be too hard. Enjoy.

Rules for Sudoku

In this Sudoku, the grid has a number of marked two cell dotted cages. The two digits in these cages form a two digit number read from left to right. The number in these cages indicates this number rounded off to the nearest multiple of 10. Numbers ending to 1-4 are rounded down, numbers ending in 5-9 are rounded up.

Click to enlarge

Polish Puzzle Championship 2016

Last weekend were the Polish Sudoku and Puzzle Championships. Jan Mrozowski won the Sudoku event and Przemysław Dębiak won the Puzzle event. You can find all the puzzles in the following links: Sudoku and Puzzle. My puzzles are round 2.

I provided one of the rounds for the puzzle championships. I've kept the same structure that I've used for the last two year with a smaller, easier and a larger harder puzzle of each type. I think it works well for these championships. I've been trying to run through different genres each year. So this year I again used nine different genres. I think it resulted in a good mix of different types.

Puzzles can be found below.

Daily League #65: Rossini Sudoku

This is the third puzzle that was originally written for the Polish Sudoku Championships.

This week it's a Rossini Sudoku. I was trying to design a puzzle without any givens. But I noticed pretty quickly on that this wasn't as easy as I had hoped. The middle of the grid is a lot less accessible as I had thought in advance. I remember seeing one before without givens, but to achieve that I'll need to set up the middle boxes better than I did now. But as I liked how the opening worked out, I finished the puzzle with a few givens. I am happy how it turned out. Enjoy.

Rules for Sudoku

In this Sudoku arrows on the outside indicate that the first three digits in that row or column, when looking from that side, are in ascending order in the direction of the arrow. All possible arrows are given, so if there's no arrow the digits can't be in ascending order.

Click to enlarge

Daily League #64: Hi-Lo Frame Sudoku

This is the second puzzle that was originally written for the Polish Sudoku Championships.

This week it's a Hi-Lo Frame Sudoku. I like the Hi-Lo concept as it gives a little bit of extra information about the third digit that isn't involved in the sum. I've written a few before, but I haven't used it for the league before. I did combine it with another variant, but it should be fun by itself. I think this is probably the hardest puzzle in the set because it requires finding the right few steps through the opening. I prefer not given all possible clues as otherwise you get a big opening on where either the 1 or 9 goes within a box. In the end the path gets a bit more flexible as you have placed digits to help out. Enjoy.

Rules for Sudoku

In this Sudoku the numbers on the outside indicate the sum of the highest and lowest digit in the first three cells in that row or column when looking from that side.

Click to enlarge

Daily League #63: Clone Sudoku

This month there were four puzzles I wrote for the Polish Sudoku Championships. They weren't needed though. As I hadn't used any of these types for the League, I figured I could use them for that. I wrote these puzzles to fit more in a competition and I expect them to be a bit easier than normal. I can never be 100% sure as I sometimes assume an opening deduction is pretty straightforward, but that doesn't mean it can't be hard to find. I'd love to hear some feedback on whether these puzzles would be suitable for a championship. I haven't written many Sudokus for competition solving.

The first puzzle is a Clone Sudoku. I thought the pattern of givens around the Clone region looked nice. I was hoping to make the pattern work with two empty boxes, but I couldn't get it unique. One extra clue did make it unique. It makes the puzzle asymmetric, but it is still a good solve.

Rules for Sudoku

In this Sudoku, digits in the same place in both grey figures must be identical.

Click to enlarge

UKPA Open 2016 Team Round: Stacked

The UKPA Open 2016 was held in Croydon on February 27th-28th. As an intermission between the competition and the ceremonies there are team rounds to keep the competitors busy so they don't cause any trouble. I provided one of the team rounds.

The concept of this team round is a bit easier than last year's. All puzzles in this set are unique by themselves. The interaction between the puzzles doesn't come till you have solved them. I tried to rank the puzzles so people could divide the puzzles between their solvers appropriately. Once you've solved all puzzles the second step of the solve comes into play. You have to divide all puzzles in three sets of 4 puzzles, one from each genre, so that all solutions, when placed on top of each other, use every cell at least once. I thought it would be an interesting idea and I think it worked out well.

I uploaded two versions of the team round onto the drive. The files contain a detailed example of the round structure. File #1 has all puzzles of the genre on a single page, easier when solving alone. File #2 has each puzzle on a single page, easier when solving together with others.

Puzzles can be found below. Enjoy.

UKPA Open 2016: Individual Round

The UKPA Open 2016 was held in Croydon on February 27th-28th. Tom Collyer was the winner of the Sudoku competition, with Mark Goodliffe finishing in second and Heather Golding in third. Neil Zussman won the Puzzle competition, with Tom Collyer finishing in second and Steve Barge in third.

I contributed an individual round for the puzzle event and a team round. This post will contain all puzzles from the individual round. The team round will be posted in a separate post.

Puzzles can be found below.

Daily League #62: Mathrax Sudoku

This is the fourth and last puzzle in the 'Latin Squares Sudoku' series. This week it is a Mathrax Sudoku. Originally I had planned a Kropki Sudoku, but after the GP I wasn't really in the mood of writing one. So instead I opted for a Mathrax Sudoku. This type has been a bit of a nemesis with me but the most recent one I actually managed to solve.

For the design I wanted to make two lines containing each type of clue once. I think it looks pretty nice. I needed two extra clues for uniqueness. It is not really a hard puzzle, especially compared to some other Sudokus on my blog. It should still be fun to solve. Enjoy.

Rules for Sudoku

In this Sudoku some intersections of the grid lines are marked by a number and an operator (+, -, x, /) in a circle. The number is the result of the operation, applied to both pairs of diagonally opposite cells. An "E" in the circle indicates that all four adjacent digits are even, while an "O" indicates that all four adjacent digits are odd.

Click to enlarge

Puzzle #188: Capsules

This is the sixteenth and last practise puzzle for this year's UKPA Open.

This type is the only one that actually fills a polyomino in the end. I've written enough of these. I always enjoy solving them. It's a simple type. This is a smaller puzzle. I find it pretty handy that both 7x7 and 8x8 grids become divisible into pentominos by taking away the corner.

Rules for Capsules

Puzzle #187: Magic Snail

This is the fifteenth practise puzzle for this year's UKPA Open.

I wanted to include a Latin square type puzzle, but many don't work that well with the digits 1-4. I needed a type that used empty squares to get a workable puzzle. Magic Snail seemed to fit the bill. I used to always have trouble with these puzzle. But since designing a few of these I got a bit more the hang of them. It's important to keep good track of the number through the outside few rows as the ordering forces a lot. It limits the placement of certain numbers in particular cells. This puzzle is not overly hard, although I accidentally sent it out with a missing clue at first. That made testing tricky. With the clue it's not the hardest.

Rules

Write the digits 1-4 once in every row and column (1-3 in the example). When traveling from the left top corner to the centre you should encounter the digits 1-4 four in order: 1-2-3-4-1-2-......-3-4.

Example

 

Puzzle

 

 

Puzzle #186: Neighbours

This is the fourteenth practise puzzle for this year's UKPA Open.

I'd never written these puzzles before. I've solved enough though. In my design I tried to form the solution form a few strategically placed digits. I think this solve worked out well, but I could probably design much trickier puzzles in this genre. It's sometimes just hard to keep track of everything. It's easy to run into no solution moments.

Rules

Place the number 1-3 trice in each row and column (1-2 twice in the example). Digits in grey cells can't share an edge with an equal number. Digits in white cells must share an edge with at least one equal number. All grey cells are given.

Example

 

Puzzle

 

 

Puzzle #185: Sum Sweeper

This is the thirteenth practise puzzle for this year's UKPA Open.

I originally intended to make puzzles that required you to fill dominoes, triominoes, tetrominoes and pentominoes. But I couldn't actually find or think of any good type for everything. There probably are types that would fit the bill. So instead I just went for a simpler way and use the number 1-2 through 1-5 for the four types.

The problem was there aren't many types that use the numbers 1-2. So I cheated a bit and co-opted the Double Minesweeper genre for this purpose. A little change of name and it makes more sense. This puzzle is pretty hard and stumped some of my test solvers. But there's a really nice logic path to find through this puzzle.

Rules

Place the numbers 1 or 2 in some cells. Clues in grey cells indicate the sum of the digits in the white cells around it.

Example

Puzzle

 

Daily League Sudoku #61: Easy As ABCDEF Sudoku

This is the third puzzle in the Latin Squares Sudoku series. This week again a familiar variant. Easy As puzzles are one of the more standard Latin Square puzzles at WPCs.

I always like to write larger Easy As puzzles with numbers as it gives a bit more freedom in designing the puzzles. It's always hard to see whether or not you can get the puzzle in the centre if you can only give the outside clues. I have seen a few larger puzzles with standard clues, but there aren't that many grids that qualify for a unique solution.
I looked for a nice opening for a while. I think this one works pretty well. With the regions it opens up a lot of new openings to try out. I picked the layout of the letters at the start and was trying to keep all number 1, 2 or 3. But in the end I couldn't find a unique solution once I got to the end without using a 4. This didn't really hinder the path of the puzzle much, so I am happy how it turned out. Enjoy.

Rules for Sudoku

Place the letters A, B, C, D, E and F once in every row, column and marked 3x3 area. Clues on the outside indicate the position of that letter in that row or column when looking from that side. E.g. A3 indicates that A is the third letter seen from that side.



Click to enlarge

Puzzle #184: Pentominous

This is the twelfth practise puzzle for this year's UKPA Open.

This was the simplest choice for the pentomino division. I like these puzzles. I wrote a few for the Dutch puzzle association, tow of which have appeared on the site so far. Most these were tricky though, so I tried to keep the puzzles a bit easier. There's a few little insights needed to solve this puzzle, but I think it solves nicely though.

Rules:

Divide the grid into pentominos, so that no two pentominos of the same shape share an edge. Rotations and reflections are considered the same shape. Letters in the grid indicate that this cell is part of a pentomino of that shape. Pentominos may contain multiple letters or no letter at all.

Example

Puzzle

Puzzle #183: L-Dissection

This is the eleventh practise puzzle for this year's UKPA Open.

I had a lot of options for tetromino division. There were a few genres from the previous WPC I considered. In the end I wen to a type I don't see that much anymore. When I first started puzzling I would see this genre more often. The rules are pretty simple, but there's not very much room for variation. This puzzle has a tricky opening, but after that it shouldn't be too hard.

Rules:

Divide the grid into L-tetrominos. Each tetromino must contain exactly two circles.

Example

Puzzle

Puzzle #182: Sandwich

This is the tenth practise puzzle for this year's UKPA Open.

I couldn't think of any triomino division puzzles directly. I knew there were domino type puzzles with triominos, but that seemed a bit weird considering I already had dominos. Then I remembered the Sandwich genre, which I had used in the 2014 countdown. I actually liked writing that, so I gave it a go. I think the puzzles actually came out pretty well. There are no real hard deductions in this puzzle, but it's a matter of looking at the right places to make progress.

Rules:

Colour some cells black. Black cells are not allowed to share an edge. Divide the remaining white cells into triominos. Each triomino must contain exactly one digit. This digit indicates how many black squares it shares an edge with.

Example 

 

Puzzle

 

 

Puzzle #181: Dominoes

This is the ninth practise puzzle for this year's UKPA Open.

The third set was all division puzzles. Domino and pentomino were quickly chosen. Tetromino had a lot of options, while triomino was hard to find something interesting.
Dominoes was the most obvious genre. this puzzle caused some issues for my testers. This kind of opening is actually something I like to put in my dominoes puzzles. Once you find it, it runs pretty smoothly.

Rules:

Divide the grid into dominoes, so that each of the given pairs of numbers appears in exactly one domino.

Example

 

Puzzle

Daily League Sudoku #60: Doppelblock Sudoku

This is the second puzzle in the 'Latin Square Sudoku' Series. I've always liked this genre. Nine by nine puzzle are normally pretty hard to accomplish, but it's possible. Adding the regions makes it much easier to construct.

This variant is pretty similar to Between 1 and 9 Sudoku, except for the fact that you aren't forced to give a given. I tried to use an opening that takes the regions into account. This puzzle shouldn't be too hard. I actually had a harder version of this puzzle, but it was a bit too much in my opinion. I didn't even have an option to make it easier without ruining most of the puzzle. I hope it's fun.

[Edit: Puzzle fixed. I made an error, forgetting 7 could be a single digit sum.]

Rules for Sudoku

In this Sudoku you have to blacken two cells in every row, column and marked 3x3 region. Then you have to place the digits 1~7 once in every row, column and marked 3x3 region. Numbers on the outside indicate the sum of the digits in between the black cells in that row or column.




Click to enlarge

Puzzle #180: Slitherlink; Filled Loop

This is the eighth practise puzzle for this year's UKPA Open.

This is what I feel is another inherently hard type. So I tried to at least create a few openings that were all based on purely Slitherlink logic. there is a point in the end usually where you aren't as free in choosing your Slitherlink clues as you still need to fit in all pentominos. I think in the end this one gets a bit harder, but if you take into account the "no three can meet" rule, you should still be able to work through.

Rules for Slitherlink

In this Slitherlink the loop has to be completely filled with the given pentominos. Each pentomino must be used exactly once. They may be rotated and reflected. Pentominos may only touch each other by a single edgNowhere do three or more pentominos meet at a point.

Example

Puzzle

Puzzle #179: LITS

This is the seventh practise puzzle for this year's UKPA Open.

If I've written more of the same puzzle type, I always find it hard to think of an opening. Usually in LITS I end up just putting down a few nice looking rooms and see if there's any interaction that I like. This combination of the letter LITS seemed to work for well. The end result worked pretty well, although it took a while to get it unique.

Rules for LITS

Click to enlarge

Puzzle #178: Tapa; Triomino

This is the sixth practise puzzle for this year's UKPA Open.

In my TVC practise series, I have become pretty proficient in writing Tapa variants. Usually my puzzles are on the harder side. Thus is won't be overly surprising that this is also a bit of a harder puzzle. This puzzle has a single opening and it's important to find it as I don't think there is any other way through it.

Rules for Tapa

In this Tapa, you must be able to divide the wall into the given triominos.

Example

Puzzle



Puzzle #177: Nurikabe; Domino

This is the fifth practise puzzle for this year's UKPA Open.

This section came about because I wanted to include some common types, while still falling within the theme. I was familiar with three variants of common type that required division into polyominos. So this was easily collected.
I haven't seen that many Domino Nurikabes, so my first go was just checking out what I could do with the genre. The opening was pretty quickly set up. The middle and end game was where it gets tricky. It all works out logically, but it's not too obvious on first sight. It took a while to get the wall to behave properly.

Rules for Nurikabe

In this Nurikabe, you must be able to partition the stream into non-overlapping dominoes.

Example

Puzzle