Overview

Nurikabe is a logic puzzle (-nurikabe- in Japanese folklore is an invisible wall that blocks roads and upon which delays in foot travel are blamed; other names for the puzzle: -Cell Structure-, -Islands in the Stream-). The puzzle is played on a grid, typically rectangular with no standard size. Some cells of the grid start containing numbers. The goal is to determine whether each of the cells of the grid is -black- or -white- according to the following rules: - All of the black cells must be connected. - Each numbered cell must be part of a white island of connected white cells. - Each island must have the same number of white cells as the number it contains (including the numbered cell). - Two islands may not be connected. - There cannot be any 2 x 2 blocks of black cells.