Kuromasu

Kuromasu (from Japanese "kuromasu wa doko da", literally "Where is black cells?"; also known as "Kurodoko") is played on a rectangular grid. Some of these cells have numbers in them. Each cell may be either black or white. The object is to determine what type each cell is.

The following rules determine which cells are which:

Kuromasu

Cross+A can solve puzzles from 3 x 3 to 30 x 30.