Kuroshuto ("Kurochute"; from Japanese, literally "black shot") is a logic puzzle invented by Nikoli. A rectangular or square grid contains numbers in some cells. The goal is to blacken some empty cells. A cell with a number indicates that only one of the cells with such distance must be blackened. Two black cells must not be orthogonally adjacent. All of the white cells must be connected.
Cross+A can solve puzzles from 3 x 3 to 30 x 30.