precept of the diamond chalice ［金剛宝器戒］ ( kongō-hōki-kai): Also, diamond precept or diamond-treasure precept. The precept that, like a diamond chalice, is impossible to break. The term appears in the Brahmā Net Sutra, which states, “This precept of the diamond chalice is the source of all Buddhas, the source of all bodhisattvas, and the seed of the Buddha nature.” In The Secret Commentary on the Aspect of the Diamond Precept, Dengyō (767–822) interpreted the Buddha nature, or the true aspect of all phenomena mentioned in the Lotus Sutra, as the diamond chalice. The precept of the diamond chalice thus means to embrace the Lotus Sutra. Nichiren (1222–1282) interpreted the embracing of the Law of Myoho-renge-kyo, the essence of the Lotus Sutra, as the precept of the diamond chalice and taught that, by observing this single precept, one can manifest the three bodies of a Buddha—the Dharma body, the reward body, and the manifested body—and receive benefit equal to that of observing all other good precepts. In The Teaching, Practice, and Proof, Nichiren writes: “The five characters of Myoho-renge-kyo, the heart of the essential teaching of the Lotus Sutra, contain the benefit amassed through the countless practices and meritorious deeds of all Buddhas throughout the three existences. Then, how can these five characters not include the benefits obtained by observing all of the Buddhas’ precepts? Once the practitioner embraces this perfectly endowed wonderful precept, he cannot break it, even if he should try. It is therefore called the precept of the diamond chalice” (481).