Problem of the Week 1077
The March 21 New York Times had a nice article by Will Shortz on several new types of puzzles originating in Japan: Inside Japan's Puzzle Palace (requires registration with nytimes.com).
I found nurikabe (also known as Islands in the Stream), invented by Nikoli, to be particularly pleasing.
This diagram gives a simple nurikabe, along with its solution:
The idea is to color each square black or white, subject to the following rules, where "connected" always means in a horizontal or vertical direction, not diagonal.
So in this 9×10 nurikabe -- Problem 1077 -- one knows immediately that the three squares connected to the "1" are black.
© Copyright 2007 Stan Wagon. Reproduced with permission.