## June 03, 2010

### Friday Puzzles #54

Again, I find myself in two minds as to how this puzzle ought to be classified. You see, the problem is most Hashi that I do are fairly generic, and probably require a solving set of about five moves applied with various degrees of imagination. With this Hashi, there are two polarised solving experiences that I can envisage you, dearest reader, having. Either something clicks, and everything gets pretty standard pretty quickly, or else you’ll struggle a little bit and the solve will turn into something of a slog.

It seems to me that the best case scenario for me as the author is that everyone manages to click. In which case there seems to be only a minor pay-off before everything gets standard. Still, having steadfastly argued earlier this week that an otherwise unspectacular puzzle still had some merit to it based on a novel and interesting move to finish it off, I suppose I should be happy with this. Enjoy!

Update: My thanks to Bryce Herd who pointed out that an earlier version of this puzzle failed to satisfy a basic theorem of graph theory!

#064 Hashiwokakero – rated hard

All puzzles © Tom Collyer 2009-10

### 3 comments by 1 or more people

1. #### Jack

Sure enough, there was a very satisfying a-ha moment where the puzzle went from “omg how is this possibly going to be unique?” to fairly smooth sailing. I like the fact (not to spoil too much) that it’s a Hashi where the center is more important/useful than the edges/corners to getting going, and where once you see the logic it feels like its been hidden in plain sight all along.

04 Jun 2010, 19:06

2. #### Bryce Herdt

I’m having a problem. I think there’s a parity issue; I count five rows where the sum of the clues is odd.

12 Jun 2010, 05:25

3. That’s a really interesting point that you raise, and a nice exercise in graph theory. I think that’s a silly mistake resulting from my trying to disguise the clues, and one that I can only assume I missed is because it only becomes apparent once you have connected up all the components, and assume that you are done!

Anyhow, it’s fixed now!

12 Jun 2010, 12:04

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## Information

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.

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## Search

• 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