On the basis of [ten suchnesses], Zhiyi formulated a grand, architectonic concept that came to be called the “single thought-moment entailing three thousand realms” (ichinen sanzen). In a famous passage, he writes: “Now a single thought [literally, “one mind”] comprises ten dharma-realms, and each dharma realm also comprises ten dharma-realms, giving a hundred dharma-realms. A single realm comprises thirty kinds of worlds; hence a hundred dharma-realms comprise three thousand kinds of worlds. These three thousand are contained in a single moment of thought. Where there is no thought, that is the end of the matter, but if there is even the slightest thought, it immediately contains the three thousand [realms].”