The Tathāgataguhyasūtra (TG) is a Mahāyāna sūtra frequently cited by śāstras, e.g., the Prasannapadā, Mahāyānasūtrālaṃkāra, etc., for its theory (A) that the Buddha never said a single word during the period from his enlightenment to his death. In this paper, firstly I shall discuss the relationship between this theory and the early Buddhist canons, and show briefly how TG used old ideas to construct its theory of “not saying a single word.” I would also like to discuss the theory (B) that Buddha’s voice (śabda) originated from the ether (ākāśa) in TG, and illustrate that theory (B) is adopted by TG mainly for the purpose of reconciling the Buddha’s not saying a single word with Buddha’s exposition of the teachings.
