Saturday, 31 December 2011

Puzzle #78: Nurikabe; No Repeat.

Happy New Years Samoa and New Zealand.

I am almost 100% sure people aren't reading my blog there, but as they are the first, I figured i'd include them.

I don't think there is much of a surprise that this puzzle incorporates pentominos. I've always liked pentomino based puzzles. I think it is because the logic puzzles allow me to actually pack all 12 pentominos. This was one simple puzzle that stumped me a lot when I was young.
At first this was going to be a Shape Nurikabe, which Thomas Snyder used in his 20/10 Decathlon. Except I ran into the problem that it is pretty hard to fit 12 pentominos in a grid and create a valid Nurikabe grid. As I didn't manage to even create a valid grid, I changed the puzzle a bit. Instead I just went for no 2 islands having the same shape. this made things easier for me. The puzzle is of medium difficulty.
Also, if someone has a good suggestion for a name, I'm completely open for it.

5. Nurikabe; No Repeat

Determine for each cell if it's part of the stream or an island. Each number is part of a single island of horizontally and vertically connected cells, which size is equal to that number. Islands can't touch eachother horizontally or vertically. The cells not part of an island form the stream. The stream is a single connected area, which doesn't cover any 2x2 areas anywhere.
Additionally, no 2 islands have the same shape. Rotations and reflections are considered the same shape.


  1. Nurikabe being my favourite puzzle,i am glad to see one here.

  2. Happy New Years from New Zealand Bram!
    Thanks for the great puzzles.
    You can never be 100% sure about anything...

    James McGowan

  3. Oh, is that where the kiwi part comes from? I've always seen you listed as UK and you did win the UK championship, so you can't blame me from missing that.

  4. I live in NZ but I'm also a UK citizen. UK has a WPC team but NZ doesn't have any puzzlers, so when online I list myself as UK and will hopefully join their team to Croatia this year. I also recently lived in Amstelveen for 2 years so maybe I'm a little bit Dutch too...? ;)