All entries for Friday 03 September 2010

September 03, 2010

Friday Puzzles #68

For this week’s puzzle, I’ve decided to have a little play with Yajilin, and its presentation.

A problem I quickly ran into was with how the clues have an effect on the puzzle. It wasn’t too long into making this that I had a nice symmetric pattern laid out in the grid, and a few clues in place. As I continued putting in more and more clues, it became increasingly obvious that I wasn’t going to need all the marked squares for clues that I’d set aside. However, I also realised that I couldn’t simply throw them away (for one thing, think of the symmetry!). But more importantly, because the rules of Yajilin say that you have to use every square in the grid, these as yet clueless squares were still playing a crucial role in the solving process.

As such I’m going to throw you two versions of the same puzzle, presented slightly differently. For the first, I filled in the the clue squares I needed, sometimes ridiculously, and sometimes a little more obscurely, all the time trying not to introduce too many logical short-cuts into the puzzle.

I am not sure then, that despite having more information in the first version, whether actually the second is a nicer solve.

#083a Yajilin – rated hard

Note in this version that you can shade in a square directly adjacent to a blank grey square, although the loop definitely cannot enter these squares. Also note that the the grey squares aren’t included in the count of the to-be-shaded squares.

I’m hoping I’ve deleted the right clues, although I suppose it’s not the end of the world If I’ve gone too far. I think it should work out that there are probably still one or two technically surplus clues hiding in there.

#083b Yajilin – rated hard

All puzzles © Tom Collyer 2009-10


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Welcome to the blog of current UKPA sudoku champion, two-time Times national sudoku champion and general logic puzzle fan Tom Collyer.



Home of the original Friday Puzzles, each Friday I publish a 100% original and handmade logic puzzle, inspired by the world-famous Nikoli company.


How to play:
AkariFillominoHashiHeyawakeHitoriKakuroLITSMasyuNumberlinkNurikabeRipple EffectShikakuSlitherlinkSudokuSuraromuYajilin.

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Latest comments

  • I like the appearance of the solution. :P Nice one. by Prasanna Seshadri on this entry
  • I think I've seen something vaguely similar in some of Palmer's puzzles as well. To be honest I've a… by on this entry
  • That's two puzzles in a row where I find something I had used before. I know, not plagiarism; just g… by Bram on this entry
  • Kota, that's not really true. I had made my puzzle before going to the WPC already. Also I don't hav… by Bram on this entry
  • About 20 minutes, after restarting from a mistaken conclusion. by Bryce Herdt on this entry

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