Here’s an Angle Loop puzzle. As seen for instance on this weekend’s Toketa? Selection contest that you should all take part in.
Puzzle 76: Angle Loop
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Author Archives: rob
Puzzle 75: Tapa LITS
The next Tapa Variations Contest is coming up: TVC XVIII. Once again, Bram is kindly sharing a set of practice puzzles (intro, part 1). To give a little bit back, here’s one more Tapa LITS.
One other of the types that will show up is Different Tapa, so solve the one from this blog if you haven’t: Puzzle 70: Different Tapa.
Rules Solve as a standard Tapa. In addition, the shaded cells must form a valid LITS solution (minus the rooms), i.e., the wall consists of tetrominos, and similar tetrominos can’t touch by edge.
Puzzle 74: Tapa knapp-daneben
To welcome the new year, here’s a Tapa “knapp-daneben”, i.e., all clues are off by one. The type features on Tapa Variations Contest XVII which takes place on the week-end. I’m really looking forward to that! For a more thorough preparation, check the practice puzzles on Bram’s blog. 
Rules Increase or decrease each digit by one, then solve as a regular Tapa. Digits may become zero, even multiple, but not negative.
Florian
Most of you have probably hear the sad news: Florian Kirch passed away last week. I can’t claim to have known him well; a little better after preparing for and competing at the WPC this year with him. That was a great experience, I’m glad I had the opportunity. The whole thing is quite a shock, more so since he seemed full of plans: He’s behind the first German youth sudoku championship that is being held this year, and was actively working towards a WPC hosted in Germany, besides a variety of activities in other fields.
If you’d like to solve some of the puzzles he constructed, I’ve collected what I was able to find. I’d be happy to extend the list. The 2015 Logic Masters certainly stands out, my favourite of his rounds there being “Vorsicht klebrig”, a set of Tapa, Fillomino and Slitherlink puzzles that had to be matched to normal, cylindrical and Klein bottle topologies.
- Rätselportal
- Logic Masters 2015
- LM qualification 2013, 2010, 2009
I’ll close by reposting a puzzle dedicated to Florian’s memory that I first published here on the portal.
Rules Glue the grid to form a Klein bottle, by identifying one pair of opposing edges directly, the other pair after flipping. Then solve as an ordinary Tapa.
Puzzle 73: Mochikoro
Here’s a Mochikoro puzzle. The type features on next weekend’s WCPN contest.
Solve at pzv.jp.
Rules Shade some empty cells, such that the unshaded cells form rectangles. Each clue is contained within an unshaded rectangle of the given area, and each rectangle contains at most one clue. Furthermore, all unshaded cells must be connected by corner, and shaded cells can’t form 2-by-2 squares.
Elsewhere
Nothing original, but a few links.
- More WPC reports: world champion Ken Endo’s report, and a behind-the-scenes look by one of the authors, Andrey Bogdanov.
- My Different Star Battle on croco-puzzle is now publicly solvable. I’m really rather pleased with how that one came out.
- I posted a somewhat different puzzle, based on the game Tic-Tac-Toe, to the puzzle portal: Tic-tac-toe reconstruction. (Click the UK flag for English instructions.) Some of you might enjoy that.
WPC 2015 retrospective: day 2, mostly
Below, continuing the story of day 1, I’ve collected some thoughts on the rest of the WPC in Bulgaria. And as before, failed to cut down the length.
Puzzle 72: Different Magic Summer
Here’s another WPC practice puzzle, a Magic Summer from the round of puzzles with different areas, just like the recent Different Tapa.
While on the topic of WPC puzzles: There’s a WPC series starting today on croco-puzzle. It’s authored by Silke and me, with a selection of puzzle types from Sofia. These are all “Ü2”, so you can solve them with no Java applet worries.
Rules Place digits in some cells, so that each row and column contains exactly digits 1 through 5.
Connected blocks of digits in a row or column form numbers by reading left to right or downwards, respectively. Clues outside the grid are equal to the sum of all such numbers within the corresponding row or column.
In addition, the gray cells must all have different content.
Puzzle 71: Color Akari
Here’s a practice puzzle that I made for the color-themed team round at the WPC. Some of the intended logic may have been lost in getting it correct, but enjoy nonetheless.
Rules Place some red, green and blue light bulbs. These shine in vertical and horizontal direction until they hit a black cell. Every white cell must be illuminated, and no two bulbs may illuminate each other. Colored clues indicate the composite color of the bulbs that illuminate it: pure red, green or blue, cyan (green+blue), magenta (red+blue) or yellow (red+green).
Or see the WPC instructions.
WPC 2015 retrospective: day 1 mostly
Below I’ve collected some thoughts on the first half of the WPC 2015 in Sofia, mostly about the puzzles and how they went for me. The second half is still to come (here), but this is getting and taking so long I think I’d better post now. I’ve collected some information from the full result table at http://www.wscwpc2015.org/wpc2015_results.xlsx, particularly the 10th best score of each round, which seems like a good point of comparison. Especially for my personal analysis, since I was hoping to take a shot at the top 10 this year.
Since this doesn’t come with any summary yet to put the inevitable criticism into perspective, I’d like to start by thanking everyone involved, but particularly the puzzle authors. While there were some issues with puzzle formatting and point allocation, and general organizational problems, the puzzles themselves were of consistently high quality; I’m not aware of a single broken puzzle.
Edit: Here’s a link to the instruction booklet.
Maybe Puzzles 