A massive space craft created by Washu and stolen by Kagato.
The Soja was a large spaceship created by Washu 5,000 years before the start of Tenchi Muyo. The ship would be stolen by her assistant, Kagato, and used as his means of traveling the universe in search of the ultimate power he sought. It is a powerful ship, easily capable of taking out an entire fleet of Galaxy Police fighter ships and has the power to destroy a planet. The inside of the ship has a reverse world that Washu was sealed in that no one can break free from so long as Kagato was alive.
Within the main chamber of the Soja are Kagato's gems. Because of their large size, Kagato is incapable of using them outside the confines of his ship. However, they serve as a powerful defense for his chamber as they can create a force field that neutralizes outside energy sources and can even absorb their power to further increase the power of Kagato and the Soja.