Puzzle No. 411-414 : UKPC 2013 Puzzles

Edit: Congratulations to Neil Zussman from UK, the overall winner.

Following up from my non-puzzle post before this, I’m still not well folks. And my laptop’s still not fixed. Overall, not a good time. I’m just hoping everything becomes fine by the time the Championships come along.

Speaking of Championships, the UK Puzzle Championship was held recently, around the same time as the IPC. I contributed 4 puzzles to the UKPC. Two of these were fairly common types, Nurikabe and Corral. I had been doing many Kurotto and Yosenabe puzzles around this time, Yosenabe in particular seemed fresh, so I used that and themed a UK into it, adding to my other UK themed puzzle, the Corral. For the other puzzle, I actually wanted to do either a snake variant or a true-false type puzzle. As is usually the cases with me I just ended up combining both and we have True-False Snake.

Anyway, to the puzzles, (with points as they were awarded to each during the UKPC).

P411: Nurikabe. 15 points.

P412: Yosenabe – Move all circles, vertically or horizontally, so they enter the grey areas. Show the movement of a circle by an arrow, with the tip of the arrow in the first cell it enters of its grey area. Arrows can cross through grey areas if they need to reach a grey area beyond. The arrows do not bend, and do not cross other white circles or lines of other arrows. The number in a grey area must be equal to the sum of the numbers of the circles which enter the area. Empty grey areas may have any sum total, but at least one circle must enter each grey area. Example with solution. 20 points.

P413: Corral. 20 points.

P414: True-False Snake – Draw a snake in the grid of unknown length. The head and tail of the snake are given. The body of the snake cannot touch itself, not even diagonally. The numbers indicate the number of cells the snake visits in the direction of the arrow. If the snake does not pass through a clue cell, then that clue is true, otherwise, it is false. Example with solution. 40 points.

Enjoy!

P411

P412

P413

P414

4 comments on “Puzzle No. 411-414 : UKPC 2013 Puzzles”

1. I liked all of them. I particularly enjoyed the Corral, both the aligned clues execution and corner cleanup were neat.
Yosenabe resulted in a lot of bad karma towards the organisers though. My understanding of standard Yosenabe rules does NOT include ”with the tip of the arrow in the first cell it enters of its grey area”. This bit I’d have liked to see highlighted, given its variant nature and how dependent speed solving is on its absence.

• I basically just made the rules based on solving the puz-pre version of the ones from http://nikolikeipuzzle.blog.fc2.com/ , where the tip of the arrow entering the first cell marks it as correct. I saw some confusion in the rules as a possibility in general, but had no idea it was a variant rule, since even for the ones I solved in my Nikoli book I just assumed that rule and they went fine.

I don’t see how the rule changes anything anyway, because at most you can probably extend the tip to some more cells in the same area. Was the key dependent on this perhaps? I participated in the UKPC but didn’t solve my own puzzles.

2. The aforementioned blog’s puzzles don’t actually require it. They consistently block arrows from possible extension by using other arrows to force uniqueness. And after solving a few, I developed an eye for uniqueness requirements, then came to rely on those for speed, and, worse, for sanity checking solutions in progress. As you can imagine, this modus operandi didn’t mesh all that well with lackadaisical reading of instructions.
None of which is to say the puzzle wasn’t rather nice. Heck, the example was nice too once I came round to it – after the contest.

• Well, fair enough, I must have missed the other arrows forcing uniqueness bit. Its my bad, should do more research before adding a newer type in. The organizers just worded the rules as I gave them. Apologies for the confusion caused.
Thanks for the feedback, and I’m glad the puzzles were nice even in the midst of all the confusion.