essential teaching ［本門］ ( hommon): Also, original teaching. (1) The teaching expounded by Shakyamuni from the perspective of his true identity as the Buddha who attained enlightenment countless kalpas ago. It consists of the latter fourteen chapters of the Lotus Sutra, from the “Emerging from the Earth” (fifteenth) through the “Universal Worthy” (twenty-eighth) chapter. In The Words and Phrases of the Lotus Sutra, T’ien-t’ai (538–597) classifies the content of the sutra into two parts—the first fourteen chapters, or theoretical teaching (also known as trace teaching), and the latter fourteen chapters, or essential teaching (original teaching). He further explains that Shakyamuni expounded these two teachings from two respectively different identities: The Shakyamuni Buddha who attained enlightenment in India expounded the theoretical teaching, while the Shakyamuni who cast off his transient identity as the Buddha enlightened in that lifetime in India and revealed his true identity as the Buddha who attained enlightenment in the remote past expounded the essential teaching. T’ien-t’ai identified the Buddha of the essential teaching as the true Buddha, and the Buddha of the theoretical teaching as the true Buddha’s provisional manifestation, or a provisional Buddha. He respectively compared the relationship between them and between their teachings to that of the moon in the sky and its reflection on the surface of a pond. In contrast with the theoretical teaching, which presents Buddhahood as a potential in the lives of all people, the essential teaching describes it as a reality manifest in the eternal life of the true Buddha. The core of the essential teaching is the “Life Span” (sixteenth) chapter, which reveals Shakyamuni’s enlightenment in the distant past. Moreover, it reveals the three mystic principles: the true effect (the original enlightenment that Shakyamuni Buddha attained in the remote past), the true cause (the practice he carried out to attain that enlightenment), and the true land (where the Buddha lives and teaches); together they clarify the reality of the Buddha’s enlightenment.
  (2) In his writings, Nichiren (1222–1282) sometimes uses the term essential teaching to indicate the essential teaching of the Latter Day of the Law; that is, the teaching of Nam-myoho-renge-kyo. The Object of Devotion for Observing the Mind reads: “The essential teaching of Shakyamuni’s lifetime and that revealed [by Nichiren] at the beginning of the Latter Day are both pure and perfect [in that both lead directly to Buddhahood]. Shakyamuni’s, however, is the Buddhism of the harvest, and this is the Buddhism of sowing. The core of his teaching is one chapter and two halves, and the core of mine is the five characters of the daimoku alone” (370). Nichiren thus identified Nam-myoho-renge-kyo, the teaching he revealed at the “beginning of the Latter Day,” as the essential teaching for that age. From this viewpoint, in the same treatise, Nichiren states: “The difference between the theoretical and the essential teachings is as great as that between heaven and earth. . . . Nevertheless, even the difference between the doctrine of three thousand realms in a single moment of life of the theoretical teaching and that of the essential teaching pales into insignificance” (368). That “difference . . . pales into insignificance” when it is compared with the difference between the essential teaching that is the latter half of the Lotus Sutra, and the essential teaching revealed by Nichiren at the beginning of the Latter Day of the Law, or Nam-myoho-renge-kyo. Hence he termed his essential teaching “the unique essential teaching” ( dokuichi-hommon) in On the Mystic Principle of the True Cause, a writing he gave his immediate successor, Nikkō. See also fivefold view of revelation.