Next one, a Semitransparent Snake. This was hardly worth constructing, since the competition puzzle was only worth 20 points. Also the type is somewhat dreadfully confusing. But, enjoy!
Rules Connect Start to Finish by a standard snake. Clues count the visible snake cells. Along any straight segment of snake cells (in the direction start to finish), every 4th cells is invisible (from both directions).
Or see the instruction booklet.
I’m starting to question my choice of posting all the linkable practice puzzles before the corresponding WPC review post… This is a great take on the standard Domino dissection puzzle that keeps the core while making it logically richer and less susceptible to uniqueness deductions.
Rules Partition the grid into areas of size three, such that each domino can be placed within one of the areas.
Or see the instruction booklet.
Next WPC preparation puzzle, this one from round 5, Variations. You might as well call it a First Seen No-Islands Tapa.
Inner coral
Rules Shade some empty cells to form a Coral, compare Puzzle 27. The clue cells count as empty cells for the coral and can not be shaded. They indicate the lengths of the first blocks seen in each of the up to four directions.
Or better see the instruction booklet.
The 27th WPC is over. Like the last time I did this, there’ll be some criticism (as there would have been for the two past years), so let me thank the authors and organizers right away for the terrific job they did. I’ll go through the competition round by round again, covering rounds 1 through 3 (morning of day 1) in this post.
Like last time, I’ll compare to the 10th best score of each round. That value is reasonably unaffected by the out-of-this-world scores at the very top.
Another WPC practice puzzle here, again from the Skyscraper themed round. It’s a pretty nice variant, though somewhat susceptible to uniqueness arguments. (Try it without, though!)
Skyscrapers with Mirrors
Rules Fill each row and column with numbers from 1 through 5 as well as a single diagonal mirror. Clues act as regular skyscraper clues, but follow the mirrors.
Or see the instruction booklet.
While I’m writing up some notes on the recent WPC (team gold yay!), here’s a practice puzzle I made, for the skyscrapers round. It’s quite a neat variant, called “first invisible”.
You can solve online (but be warned that the solution isn’t checked correctly).
Rules Fill the grid like a usual skyscrapers puzzle. However, instead of counting visible buildings, clues indicate the first non-visible building from that side.
Or see the instruction booklet.
Next weekend I’m running a pure Killer Sudoku contest at logic-masters.de. The idea was to give our Killer Sudoku experts a chance to shine. It’s 9 puzzles in 90 minutes from 6 authors, see the instruction booklet for further details. Thank you to Tom Collyer, Stefan Heine, DavidMcNeill, Eva Schuckert and Bernhard Seckinger for their contribution!
To get you in the mood, here’s one Killer Sudoku.
Rules Solve as a regular Sudoku. In addition, some cages are given. The cage clues indicate the sum of the digits within the cage. Digits can’t repeat within a cage.
Here’s another puzzle I made in preparation for the recent Logic Masters. It’s a Minesweeper Tapa, a type from the Tapa round on the contest.
In other news, results have now been posted: https://logic-masters.de/LM/2018_e_tabelle.php. (It seems linear time bonus really isn’t the right choice where players finish after a fraction of the round: On round 6 I took 3.5 minutes compared to the next player’s 5 minutes, for a factor 1.06 in points.)
Rules Solve as a regular Tapa, except the clues just specify the total number of shaded cells in the surrounding cells, as in Minesweeper.
Posting from the evening after the 2018 German Logic Masters. It went decently well for me, with a third place after the main rounds which means I’m on the A-team again. My results on the two Rätselportal-rounds were bad as expected. On the other hand, finishing that fences sprint round first with quite a margin after 3:15 of 20:00 minutes was great. An unfortunate marking mistake in the final playoffs saw me lose a couple of minutes of time double-checking my correct solution. With no good way to fix this, I ended up fourth with the knowledge that first place was possible.
I made a couple of puzzles to prepare, two of which I’ve published on the Rätselportal already: A Japanese Sums/Masyu hybrid and a hand-constructed (with the help of a friend, thank you!) unclued 5×5 skyscraper blocks that I’m very happy with!
Some more I’ll post here. To start, here’s a The Largest Number. The type was introduced at the 2017 WPC in India. I don’t think I’ve seen one without given numbers before.
Rules Fill the grid with numbers such that each room contains the numbers from 1 to the size of the room. Equal numbers can not be next to each other horizontally or vertically. Circle the largest number in each room. Then also circled numbers can not be next to each other horizontally or vertically.
Here’s a new (?) Sudoku variant. Inspired by Sudoku N from the upcoming Sudoku Mahabharat. The 6×6 example there also solves uniquely by these rules.
Rules Solve as a regular Sudoku. Some pairs of numbers are friends. Dots mark all spots where two friends are next to each other.
Maybe Puzzles 