It's been four years since I posted on my blog. It's also been four years since I wrote practice puzzles for anything. Most puzzles I've written in the last years have either appeared on the Dutch team website wcpn.nl, Sudoku and Puzzles Down Under on Facebook or in different national championships. This post will contain all practice puzzles I wrote for this year's World Puzzle Championship in Krakow, Poland.
The championship itself was a lot of fun. The puzzles were very nice. I was introduced to some fun new puzzle types. La Paz and Rail Pool were definitely my two favourite new types. Those puzzles were a lot of fun to solve. Pretty much every new type had something interesting though. The Nightmare in Krakow round was a fun combination of rule variants. The No Four In A Row concept led to some interesting puzzles. These two were my favourite two variant rounds.
The championship went better than I expected. I hadn't really gotten around to competing much in the last few years. I had lost my drive a bit during COVID to compete in the GP or other online competitions. I wasn't really sure how well my solving skills had kept up. At the championship it turned out that I was still able to compete with the best puzzlers. I had a good start to the championship and avoided errors through the first 4 rounds. I ended up in 4th place after 4 rounds, which was a lot better than I was expecting at the start. After this a few errors started sneaking in. I broke a couple puzzles in the Snake round and also made an error on a third puzzle, so I dropped off a bit after this round. The second day got worse over the day. I made some small errors that lost me some points in the morning, but the big errors came in round 11 and 12. A small error in round 11 cost me over 200 points for the puzzle and the time bonus. Round 12 just had a number of dumb errors in a couple of puzzles. In the end I managed to make it to the playoffs in 10th place (12th unofficial). Philipp Weiss just managed to edge me out in the playoffs because I broke the BACA on the first go and had to restart it. A good solve on the Star Battle Builder got me pretty close, but I couldn't find the solution in the bottom of the Shimaguni fast enough.
Overall I'm pretty happy with how the championship went. I'm still hoping to reach the podium one time and at least this championship shows I can still compete with the best in the world.
WPC Practice Puzzles
There's some nice puzzles in this set in my opinion. Not all turned out exactly as I wanted them, but there wasn't that much time to design them. I hope you enjoy them. All puzzles can also be found in this Google Doc. I also included Penpa links to all the puzzles. They're both in the file and underneath the images in this post. This is the first time I made them myself, so I hope they all work properly. If not, I'll try to fix them.
La Paz
I was looking to make an opening that didn't use any number over 3. I think this one turned out pretty well.
Rules: Shade some cells so that no two shaded cells are orthogonally adjacent and divide the remaining unshaded cells into two-cell regions. Clued cells cannot be shaded. A clue indicates the number of shaded cells which lie entirely within the same row or column as the region containing the clue.
Rail Pool
I still need to learn a bit about this genre. This was my first attempt. I made some symmetrical regions and blew up one side. Then I tried to avoid using the same number in symmetric regions, which turned out okay.
Rules: Draw a non-intersecting loop through the centers of all cells. Clues represent all of the different lengths of the straight line segments that are at least partially contained within the region. Each number within a region must be represented by at least one line segment. Each ? represents a positive integer, and numbers cannot repeat within a region.
Star Shaka
Clues with the number 2 are very powerful in this genre, so I tried to avoid them as much as possible. Clues with the number 0 are interesting as negative information can be very powerful in Star Battle puzzles as well.
Rules: Place a star into some empty cells so that every row and column contains exactly 2 stars. Stars must not be placed in cells which touch along an edge or at a corner. A numbered clue indicates how many stars are placed in the (up to) four cells sharing an edge with that clue.
https://tinyurl.com/2a3f76k9
Masyu Crossing
Designing puzzles from the Nightmare in Krakow round were good for headaches in general. It's hard to not get stuck in some simple logic from the normal genre. This Masyu turned out pretty good, although it took a few times to get right.
Rules: Draw a loop through the centers of some cells that passes through every circle. Two perpendicular line segments may intersect each other, but not turn at their intersection or otherwise overlap. The loop must turn on black circles and travel straight through the cells on either side. The loop must go straight through white circles, and turn in at least one of the cells on either side.
Star Battle Toroidal
This type is very restrictive. It would probably be more interesting in a larger size. You only need 5 of the regions to have a unique puzzle. You can probably figure out which ones.
Rules: Place stars into some cells such that each row, column, and outlined region contains exactly 2 stars. Stars may not touch one another, not even diagonally. The grid is toroidal, which means that the first and the last rows/columns are considered adjacent.
https://tinyurl.com/27calboh
Pentominous Liar
I really like how this puzzle turned out. I had an idea and managed to execute it exactly how I wanted to.
Rules: Divide the grid into regions of five orthogonally connected cells so that no two regions of the same shape share an edge, counting rotations and reflections as the same. Clued cells must belong to a region with the pentomino shape associated with that letter. In every row and column there is exactly one clue that’s incorrect.
Tapa-like Loop Crossing Toroidal
I had fun designing this puzzle. It has some nice logic for this genre. Most of it didn't really come back in the actual puzzle in the championship.
Rules: Draw a loop through the centers of some empty cells. Two perpendicular line segments may intersect each other, but not turn at their intersection or otherwise overlap. Clues represent the numbers of consecutive cells occupied by the loop each time it enters the (up to) eight cells surrounding the clue. The grid is toroidal, which means that the first and the last rows/columns are considered adjacent.
Myopia Crossing Liar
This took a lot of effort to design. After I was done with this design, I had enough of design for this round. There's some interesting things in this puzzle, but I did have to add some extra clues to make it unique. If I'd had more time, I would have probably tried to make some changes.
Rules: Connect some pairs of orthogonally adjacent dots to form a single loop. Two perpendicular line segments may intersect each other, but not turn at their intersection or otherwise overlap. Clued cells contain arrows indicating all of the orthogonal directions in which a loop segment appears closest to the clued cell. In every row and column there is exactly one clue that’s incorrect.
https://tinyurl.com/2bhxb4rw
Aqre Borders
This is only the second Aqre puzzle I've desgined. I'm still trying to understand this genre. IT takes me a lot longer than many others to make my way through any Aqre puzzle. This was definitely noticable in the tournament against Ken Endo, who was done with his Aqre puzzle before I was even really starting my solve.
Rules: Shade some cells so that all shaded cells form one orthogonally connected area. A pair of cells separated by a bold border must contain one shaded cell and one unshaded cell. There may not exist a run of more than three consecutive shaded or unshaded cells horizontally or vertically anywhere in the grid.
https://tinyurl.com/24h9z2h3
Tapa No Four In A Row
The fact that this genre keeps its no 2x2 rule, makes the wall much more restrictive. I had the idea of just keeping the centre completely open and that worked out nicely.
Rules: Shade some cells so that all shaded cells form one orthogonally connected area. Clues cannot be shaded, and represent the lengths of the blocks of consecutive shaded cells in the (up to) eight cells surrounding the clue. No 2x2 region may be entirely shaded. In addition, there may not exist a run of more than three consecutive shaded or unshaded cells horizontally or vertically anywhere in the grid. Clued cells are considered unshaded.
Nurikabe No Four In A Row
As the rules mentioned question mark clues, I expected the puzzle to have as many question mark clues as possible. So I decided to make a puzzle with as few numbered clues as possible. I think it worked out pretty well. The same wall restrictions as in Tapa were in play here as well.
Rules: Shade some cells so that all shaded cells form one orthogonally connected area. Clues cannot be shaded, and every orthogonally connected area of unshaded cells contains exactly one clue, the value of which represents the size of the area. No 2x2 region may be entirely shaded. Each ? represents a positive integer. In addition, there may not exist a run of more than three consecutive shaded or unshaded cells horizontally or vertically anywhere in the grid. Clued cells are considered unshaded.
Nurimisaki No Four In A Row
This is the first Nurimisaki puzzle I've designed. As there are only two valid number clues in this puzzle variant, I wasn't expecting any numbered clues.
Rules: Shade some cells so that the remaining unshaded cells form one orthogonally connected area. No 2x2 region may be entirely shaded or unshaded. Circles mark every instance of a cell which is unshaded and orthogonally adjacent to exactly one other unshaded cell. If a circle contains a number, it indicates how many cells are in the straight line of unshaded cells coming out of the cell with the circle, including itself. In addition, there may not exist a run of more than three consecutive shaded or unshaded cells horizontally or vertically anywhere in the grid.
Mochinyoro No Four In A Row
I thought the No Four In A Row rule worked really nicely with this genre. This was the first puzzle I designed in this type, but I thought the variant helped the design a lot. The 3 clue in this puzzle appeared in the exact same place in the championship puzzle, so that was nice to not have to think about it there.
Rules: Shade some cells so that all areas of orthogonally connected unshaded cells are rectangular and all areas of orthogonally connected shaded cells are not rectangular. The unshaded rectangles must all be connected diagonally. Clues cannot be shaded, and represent the number of cells in the unshaded area they belong to. An unshaded area of cells cannot contain more than one clue. No 2x2 region may be entirely shaded. In addition, there may not exist a run of more than three consecutive shaded or unshaded cells horizontally or vertically anywhere in the grid.
Fillomino No Four In A Row
This variant really called for some larger Fillomino regions. I don't usually design my Fillomino puzzles with very large numbers. This puzzle is very much a packing problem, which you don't see very often in Fillomino.
Rules: Divide the grid into regions of orthogonally connected cells. Two regions of the same size may not share an edge. Clued cells must belong to a region containing the indicated number of cells. In addition, no region may contain a run of more than three consecutive cells horizontally or vertically.
Cave No Four In A Row
Cave clues in this variant only have four options. I liked the opening I created and tried really hard to avoid the one misplaced clue. I couldn't figure it out though and the championship was almost starting so I settled on this. It's a nice puzzle to solve.
Rules: Shade some cells so that the shaded cells are all connected orthogonally by other shaded cells to the edge of the grid, and the remaining unshaded cells form one orthogonally connected area. Clues cannot be shaded, and represent the total number of unshaded cells that can be seen in a straight line vertically or horizontally, including itself. In addition, there may not exist a run of more than three consecutive shaded or unshaded cells horizontally or vertically anywhere in the grid.
Hey Bram, thought I’d show a bit of old-fashioned blog love and appreciation! Good to see you in Krakow and very interested to read your thoughts on how it went - the no four in a row/disconnect four/whatever else were calling it certainly seems to have captured the collective imagination. As ever I’m impressed by both quality and quantity of preparation material you put together in the small window between IB release and the competition itself.
ReplyDeleteI enjoy all puzzles. Thank you for creating and publishing them!
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