Container Division (Yokibunkatsu) grid contains stars in some cells. The goal is to divide the grid into regions of exactly five cells. Each region contains a star. The cells of the region must be foldable to a cube, with the star at the bottom and without the top side ("roof"). Some sections of borders between regions have already been given. The grid may contain cells that belong to no one region.
The primary goal is to partition the grid into distinct regions, each comprising exactly five cells. An essential rule is that every region must include a single star. The most intriguing aspect of this puzzle is the spatial reasoning involved: the five cells within each region must be arranged in such a way that they can be folded into a three-dimensional, open-topped cube, with the star positioned at the cube's base.
The following is a common structure diagram of the five cells and stars: