# Puzzle 154: The Largest Number

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.

# Puzzle 152: Masyu No-Touch

Another one for the GP. This is a Masyu with the extra rule that unused cells can’t touch by edge.

Solve and check your solution here, or use PZV (but that doesn’t verify the no-touch rule).

# Puzzles 145, 146: Masyu

Towards the end of last year Grant Fikes ran a puzzle construction contest on his blog: instructions, results. With the aid of random.org, I managed to defend the title from the previous Logicsmith Exhibition, tied by score with Nikola Zivanovic.

The objective was to construct a 10×10 Masyu puzzle that leaves over a battle ship fleet of empty cells while minimizing the number of clues. That turned out to be quite a fun challenge, and led to some rather nice puzzles, which I didn’t quite expect. I was a bit worried the contest would be won by optimal computer-generated submissions, but it seems no one went to that effort. Instead, I’m left curious as to how close to the optimimum we got with 8+7 clues.

Here are my two submissions (rules).(solve on pzv.jp)

# Puzzle 36: Masyu Reconstruction

Second to last in the series, this is a Masyu Reconstruction. The one on the contest turned out to be pretty similar in style. The type could also go another way, with a heavier focus on making a puzzle unique with few givens.

Rules Place black and white pearls in some cells to form a valid Masyu puzzle, such that the clues in a row or column are equal to the outside givens in that order.

# Walkthrough: Puzzle 20, Masyu

Here’s a walkthrough for puzzle 20, a small but tricky Masyu that hinges on an obscure technique that I’ve recently failed to explain well. Of course, I encourage everyone to try to figure it out on their own, maybe using the hints from the comments on the original post. Here’s the puzzle, spoilers after the break. Continue reading

# Puzzle 20: Masyu

Another one from the Masyu series. This one I’m happy with. It just wouldn’t have made a good contest puzzle since no one would take the time to find the logical path.

EDIT: Solve at pzv.jp.