Nurikabe (puzzle)

Two same-color cells are considered "connected" if they are adjacent vertically or horizontally, but not diagonally.

Nurikabe was first developed by "renin (れーにん)," whose pen name is the Japanese pronunciation of "Lenin" and whose autonym can be read as such, in the 33rd issue of (Puzzle Communication) Nikoli at March 1991.

Rather, a series of simple procedures and rules can be developed and followed, assuming the solver is sufficiently observant to find where to apply them.

The greatest mistake made by beginning solvers is to concentrate solely on determining black or white and not the other; most Nurikabe puzzles require going back and forth.

(Those familiar with Go can think of undetermined cells next to various regions as "liberties" and apply "atari" logic to determine how they must grow.)

Example of a moderately difficult 10x9 Nurikabe puzzle
Solution to the example puzzle given above
A Nurikabe puzzle being solved by a human. Dots represent the cells that are known to be white.
An example of the third advanced strategy. The cell diagonally between the two islands has to be black.
An example 8x8 Mochikoro puzzle.
Solution to the previous puzzle.