Monday 31 December 2012

Puzzle #145: Regional Yajilin

The higher numbers are always a bit trickier to find genres for. Last year's Island puzzle was a rare spark of genius as a choice, in my opinion. This year it's a Regional Yajilin. I spend a while looking for a good opening for this genre with the number 8. A few options didn't really lead to any good puzzles, but I think this one really worked very well.
I'm really happy with how it turned out. It's probably a bit challenging, because people aren't as used to how the black squares can be placed in this genre.

8 - Regional Yajilin

Rules for Regional Yajilin

Click to enlarge


  1. There is something inherently wrong about "a bit challenging" if my solution path includes proving that a certain part cannot have 5 black squares, so another part must have at least 2 black squares. (Only "a bit" challenging? It's "very" challenging.) But it might be only me missing something less insane.

    But great puzzle. I learned a few new tricks (3x2 rectangle can only have at most 2 black squares, for example), and how to apply it in such huge regions.

    1. Maybe that's true. I guess it's a matter of perspective. It's clear to me that there is only one way to colour 4 squares in the bottom 2 rows of that region, and seeing that neither of the remaining 2 squares there could possibly be coloured with that configuration is not too hard.
      I guess it's similar to large numbers in Heyawake, with which I have problems, except because I'm far more familiar with Yajilin, this comes much easier to me.
      But no, I'm not aware of another way to solve it.