This is a Nikoli original.
Puzzle and Goal
An unsolved puzzle consists of a rectangular grid with rectangular regions. Some of the regions may contain numbers.
The goal is to color some of the cells.
The solved grid must satisfy the following conditions:
Clues represent the number of black cells in a particular region. Clues may be black.
Black cells cannot be orthogonal neighbors.
All white cells are orthogonally adjacent.
Ortogonally adjacent white cells in the same rank cannot cross into three regions.
Divide into Rooms