Nippon is a System of uninhabitable planets, that have been made habitable by their owners. The system is currently ruled by Emperor Karahito.
The industrious people of old Japan would not be deterred by a System of dead worlds. They took all of these atmosphere-less worlds, and built warrens within them, and domed cities on their surfaces. The three main planets of the Nippon system now hold a collective total of 40 Billion people, with another 300 million working the Gas Giants and Asteroid belts in the system.
The System specializes in the mining of raw materials, and the manufacturing of goods through heavy industrial capacity. With a system that can mine, refine, and manufacture all in one location, Nippon should be an economic powerhouse. However the System barely scrapes by financially. They have more bad luck, and difficulty with space travel than most, many believe this to be due to their secular leanings, but officially they have just had a 500 year string of bad luck.