third doctrine ［第三の法門］ ( daisan-no-hōmon): The doctrine revealed by the third part of the threefold comparison known as the threefold secret teaching, i.e., the comparison of the “surface” (text) and the “depths” (implicit principle) of the “Life Span” (sixteenth) chapter of the Lotus Sutra. It is Nam-myoho-renge-kyo. In his writing The Third Doctrine, Nichiren states: “Nichiren’s teaching represents the third doctrine. Though the first and second doctrines have been spoken of in the world rather vaguely, like a dream, the third has never been spoken of at all. Though T’ien-t’ai and Dengyō explained it to some extent, they did not clarify it fully. In the end, they left it for now, the Latter Day of the Law” (855).
  In explaining this, Nichikan (1665–1726), the twenty-sixth chief priest of Taiseki-ji temple, cites the three standards of comparison of T’ien-t’ai from his Profound Meaning of the Lotus Sutra: The first standard is whether people of all capacities can attain Buddhahood through a particular sutra. The sutras other than the Lotus Sutra do not reveal that all people have the potential for enlightenment, because, according to the sutras, people’s individual capacities are fixed. In contrast, the Lotus Sutra clarifies that all people are capable of attaining enlightenment because all of the Ten Worlds, including Buddhahood, are mutually inclusive and inherent in their lives. This is explained in the “Expedient Means” (second) and “Simile and Parable” (third) chapters of the theoretical teaching (first half) of the Lotus Sutra.
  The second standard is whether the process of teaching, i.e., the process of planting the seed of Buddhahood in people’s lives and finally harvesting its fruit by leading them to Buddhahood, is revealed in full. In contrast to the Lotus Sutra, which makes clear when Shakyamuni’s instruction of the people began and ended, other sutras do not reveal this. This is explained in the “Parable of the Phantom City” (seventh) chapter in the theoretical teaching of the Lotus Sutra.
  The above two standards show the superiority of the Lotus Sutra over the other sutras.
  The third standard is whether the original relationship between teacher and disciple is revealed. “Teacher” refers to the Buddha. The “Life Span” chapter of the essential teaching (latter half) of the Lotus Sutra reveals that Shakyamuni originally attained enlightenment numberless major world system dust particle kalpas in the past, and that ever since then he has been teaching his disciples. The other sutras say that Shakyamuni attained enlightenment in this life in India, and that his disciples first became his followers in this life.
  This third standard is used to demonstrate the superiority of the essential teaching of the Lotus Sutra over the theoretical teaching.
  T’ien-t’ai’s first and second standards, Nichikan says, correspond to the first part of the threefold secret teaching, or the theoretical teaching of the Lotus Sutra. T’ien-t’ai’s third standard corresponds to the second part of the threefold secret teaching, or the essential teaching of the sutra. When compared with the threefold secret teaching, T’ien-t’ai’s three standards of comparison fall into two categories. Thus Nichikan concludes that the third part of the threefold secret teaching, Nam-myoho-renge-kyo hidden in the depths of the “Life Span” chapter, is the third teaching, or third doctrine.