Wednesday, January 9, 2008

Hashiwokakero

or simple Hashi is another one of those wonderfuly addictive logic/math puzzles with a non-English name.

The Rules (from wikipedia):

Hashiwokakero is played on a rectangular grid with no standard size, although the grid itself is not usually drawn. Some cells start out with (usually encircled) numbers from 1 to 8 inclusive; these are the islands. The rest of the cells are empty. [Other sites report that there should be one and only one solution, a'la Sudoku]

The goal is to connect all of the islands into a single connected group by drawing a series of bridges between the islands. The bridges must follow certain criteria:

  • They must begin and end at distinct islands, travelling a straight line in between;
  • They must not cross any other bridges or islands;
  • They may only run orthogonally;
  • At most two bridges connect a pair of islands; and [so 0, 1, or 2 bridges may connect two islands, but no other number]
  • The number of bridges connected to each island must match the number on that island

[NOTE: I will post the site I got the puzzle later ... it has a nice interface that makes trying solutions a lot easier, but I didn't want to give it away before someone figures it out the old way. :-p I am a mean bugger aren't I?]

2 comments:

Benjamin P Lee said...

Here is the solution:

Jan 9 Hashi Solution

The site I found it on is here

Sadly you have to sign up, but its free and they have a fair number of these games on there and a pretty handy assistant that allows you to click on the connectors or islands to add bridges which makes solving things easier.

I tried to find a way to directly access a game, but it wouldn't let me without logging in.

Kudos to mrLee to solving it by hand.

Anonymous said...

I've been meaning to solve this for a long time now, and finally got a chance last night. I've never seen this game before and I wasn't clear on the rules so I went to wikipedia to see if there was anything else it could tell me. Man almighty, a picture really is worth a thousand words! There's an image of a solved puzzle, and it made the rules became so clear. It took me about 20 minutes to solve it, and I had Kevin double check it just to make sure.

Once I started solving it, I realized I've done this before, but never in this puzzle form. It finally occurred to me that I was thinking of chemistry class when you have to draw the molecules with a certain # of "bridges" (C=4, H=1).

Good puzzle!