Nurikabe is a boardgame implementation of the Japanese puzzle game by the same name. The object of the game is to build up walls (black stones) and gardens (white stones) until the board is filled. The final configuration which the player must discover is determined by two constraints, inspired by the game of go:

1. The Gardens

All the white pieces are attached to the initial white stones on the board. The number of stones in each cluster is equal to the number on the starting stone. No two starting stones may be connected.

2. The Walls

All of the black stones are attached to a single wall surrounding the white gardens. The walls are single-thickness, so no 2-by-2 set of points may contain four black stones.