Foundations of T'ien T'ai Philosophy, p 166-167“[T]ranscendental” means that in whatever place, there the Lord of the Four Teachings distinctly exists in various bodies, with various words, and gives various sermons. [At some times and places] he hides his grand body of immeasurable virtues and is manifested as six feet tall, shining gold and purple. [At other times and places] he does not preach the sweet taste and eternal pleasure [of nirvāṇa] but the bitter taste of transiency. For him [as Śākyamuni] to reject the royal robes and pick up the dung pot is called an “expedient means” [upāya]. If he opens the gate of expedient means and reveals the aspects of true reality [as in the Lotus Sūtra], the body one faces is the perfect and eternal body; the Dharma one faces is the perfect Dharma; the practice and reality one faces are all true reality.
In this way, although these are all the shared teachings of one voice [of the one eternal Buddha], there are distinctions such as Hinayāna and Mahāyāna. Although there are long and short as to the capacity [of sentient beings] to receive, that which is revealed is ultimately only one. Various terms name one ultimate [reality]. Only one ultimate [reality] is given many names. To discuss the shared and distinct aspects of teaching, practice, and reality in this way makes it difficult to understand the [distinct] aspects, but easy to clarify [the one underlying principle of] reality.