Tuesday 22 November 2011

Puzzle #56: Yajilin

As might be expected, I also put in a few Loop based puzzles as those are my favourites.As my small Yajilin puzzles have all gotten a lot of positive feedback, I thought it would be good to put one in the set as well. I was really happy with the way this puzzle worked out. I started as I start all my Yajilin puzzles by defining the squares that will contain clues. Along the way I got to a nice unique puzzle, but hadn't used the 2 corner squares. I couldn't place clues in them, without ruining the logic I had built in. So I decided to keep those as empty clue squares and not let the loop run through them.
I think this puzzle is a little bit harder than the previous 2 10x10 Yajilin puzzles I have posted.

Rules for Yajilin

There's an additional rule, that no black bordered square can be used by the loop.


  1. So I guess this is something I must have subconsciously picked up on from seeing yajilin on your blog before, but this week I'm planning on putting together some fairly tricky yajilin together with the idea of thickening the border of "clued" cells. I've played around with various notions of shading the cells in question, but I think this one is a winner - not least because it remains essentially faithful to the "classic" presentation.

    I've made puzzles which I find are more interesting when you add more of a simple loop flavour to proceedings, but obviously having to clue each one of these unused squares makes it pretty challenging to ensure your intended logic doesn't get short-cutted by something more trivial.

    Nevertheless, with this grid what I might have been inclined to do if I was feeling particularly "purist" about things (indeed I've done so in the past) is to have arrows in those corner squares clued 0 and pointing off the grid!

    Incidentally, thanks for a typically challenging puzzle!

  2. I hadn't realised at first bordering the squares wasn't common. I'm not a Nikoli member, so don't have very much exposure to the genre. I just made this puzzle right after I made the Castle Wall puzzles. So I used the same lay out as Palmer uses for Castle Wall.

    I hadn't actually considered putting 0's pointing out in. Maybe it happens more often in Nikoli puzzles, I don't know. It seems somewhat useless to me.