Komyo means luminosity, light, or brightness. Such light has been revered in Buddhism since ancient times, and has both a physical and a mental or spiritual side. Generally speaking, idealistic people believe in spiritual light whereas materialistic people only believe in physical light, but according to Buddhist theory, brightness has both a physical side and a mental side. In this chapter Master Dogen explained this brightness. He explained that the Universe is our own brightness, that the Universe is just brightness, that our behavior in the Universe is brightness, and that there is nothing other than brightness.