World Puzzle Championship 2023

This post is a bit late. I never really got around to posting these puzzles. There's some nice puzzle in the set, so I figured I'd still share all of them.

I focussed my writing mostly on Rounds 7 and 20. They contained the most types I hadn't seen before.  I also played around a bit with round 13. I think I got the most out of writing puzzles for round 7 as I could actually keep up pretty well with Ken Endo, finishing in second place only slightly behind.

Puzzles can be found below.

World Puzzle Championship 2022

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

World Puzzle Championship Puzzles - Round 12

The last set of puzzles are from round 12. This was the innovative round. There were a few types in there that were interesting to write. My favourite two types were Inner ABC and Coral with Letters. I think those are also the nicest puzzles in this set. One rule that popped up a lot in this championship was the "Worms" rule of alternating higher and lower digits within a path of numbers. It's probably not a rule that will be used much in the future. It didn't really strike me as a rule that added much to any of the puzzles.

World Puzzle Championship Puzzles - Round 6

Round 6 had puzzles that were all combinations of different types of puzzles. There were some interesting ideas, but I doubt many of these will be seen more often again in future puzzle sets.

There's a few puzzles in here that I'm pretty happy with. The Starwacky puzzle is a nice solve. Snail on Snake worked out pretty well because it didn't need any extra given numbers, except for the head and tail. Galaxies and Tetrominoes is my favourite in the set, because it really forces the two types to work together.
The other puzzles should also be nice to solve.

World Puzzle Championship Puzzles - Round 3

I wrote a number of practice puzzles for myself, to help prepare for the World Puzzle Championships this year. I didn't have as much time to prepare, but it helped in the long run. Some people wanted to see them afterwards, so I promised to post them all on my blog.

I only really made puzzles for three rounds on the championship: Round 3, Round 6 and Round 12. This post contains puzzles from Round 3.
Most puzzles were overall a bit harder than the puzzles at the actual championship, because I took a bit more liberty with the design of most puzzles, especially in the amount of clues given. One puzzle ended up being broken, but I guess it still helped in a way to find out the logic in the genre.
For examples, please check the WPC instruction booklet.

WSC Practice #9: Round 12 - What Is It?

This is the 9th practice puzzle for the 2017 WSC.

These are the last 2 practice puzzles for the WSC. I'll be focussing on the WPC a bit for the next week. That's the championship where I'm actually competitive. I don't know whether I'll be posting puzzles yet for the WPC, but they might show up.
Nine posts also seems the appropriate number for a Sudoku competition. This time they are two practice puzzles for the instructionless round.
If someone has any specific request for a puzzle type, I might be persuaded to make another. Let me know.

I figured this is a round that might need some practice too. I don't think for either puzzle the rules are too hard to figure out. It's possible that both ideas have been done before. I can't remember seeing them before, but my memory isn't perfect. They're not exactly innovative ideas.
I think the first puzzle is probably more like a puzzle in the actual test. It's a just simple addition to a Sudoku grid. I had fun writing them, but with a bit more time I could have made them a bit nicer.
The second puzzle I'm not sure whether it qualifies as a Sudoku puzzle. It has all the rules of a normal Sudoku puzzle but it doesn't uses numbers like most Sudoku puzzles. I think the rules are pretty simple. I had a lot of fun writing them, so they should be fun to solve, I think.
Try the examples too. They're both fun puzzles too.

Rules for Sudoku

In this Sudoku the additional rules are not given. An example and solution are given of the Sudoku variant. Figure out the additional rule from the example and solve the puzzle.

Rules Puzzle #1 (highlight if needed): Each marked 2-cell area contains a 2-digit number, read left to right or top to bottom. The first marked 2-cell area seen by an arrow must contain a larger 2-digit number than the arrow.
Rules Puzzle #2 (highlight if needed): Place 8 arrows (fghimlkj) once in every row, column and marked 3x3 area. Numbers in the grid indicate how many arrows are pointing at that cell.

Puzzle #1

Puzzle #2

 

WSC Practice #8: Round 13 - Puzzle 7: Joker Product Sudoku

This is the 8th practice puzzle for the 2017 WSC.

The Joker round is going to be a tricky one. I made an error in the construction of the previous Joker puzzle. Hopefully There are none in these. It's easier to make an error in these puzzles if you just fall back into your standard deductions.
This type actually appears twice in the championship as it also appears in the final team round.
The first puzzle should be a nice solve. I put in a few things that can be done with the Joker in this genre. I'm pretty sure they were easily figured out by yourself, but I think they're nice to see in a puzzle. There's still a few key deductions to find, but it should work well.
The second puzzle is much harder. It relies on a lot of clue interactions, without giving much direct information. It takes a long chain of interactions to place a few digits and consequently figure out the Joker. Even then it's not exactly easy.
I had to check a possible error. I realised I might have forgotten something, but it didn't really influence the puzzle as the deductions still held true. The dumb construction errors really don't allay my fears of making errors in this round by accidentally forgetting a Joker interaction.

Rules for Sudoku

In this Sudoku, numbers on the borders of two cells indicate the product of the digits in those 2 cells. Additionally, there is a Joker digit in the grid. This digit can take on any integer value from 1 to 9 necessary to comply with the rules. It can even take multiple different values within a single cell to satisfy different clues.

Puzzle #1

Puzzle #2