The Tripitaka Teaching this corresponds to pre-Mahāyāna teachings as found in the Chinese Āgamas or the Pāli Canon and is directed to the śrāvakas (voice-hearers) who strive to become arhats (those who escape from this world of birth and death and do not return). It emphasizes emptiness and approaches it through analysis of the aggregates and the links of dependent origination. In other words, this teaching aims to reveal the emptiness of the self by examining the components of existence such as the five aggregates of form, feeling, perception, mental formations, and consciousness. It is shown that each of these is impermanent, subject to suffering, and cannot be the basis of an abiding independent self either alone or together. The links of dependent origination reveal the succession of causes and effects that make up existence and likewise reveal that an abiding self cannot be found therein. By doing this, the śrāvakas will realize the contingent nature of the self and thereby extinguish greed for what could satisfy the “self,” anger in regard to what threatens such a “self,” and ignorance regarding the selfless nature of the aggregates. In this way they will realize nirvāṇa and free themselves from birth and death. It might be asked: “What are the aggregates if they are not a self?” Do they somehow exist in their own right in some manner? And who is it that is free of birth and death and who enters nirvāṇa if there is no self? These are questions that are taken up in the following teachings.

The Shared Teaching — this corresponds to the Perfection of Wisdom sūtras and is directed to the more advanced śrāvakas and those just starting out on the bodhisattva path. Because these teachings are directed at both śrāvakas and bodhisattvas it is called the teaching they share in common. This level of discourse approaches emptiness more immediately or intuitively because it does not involve analysis. Rather, one learns not to impute substance or a fixed nature onto things in the first place. It is also more thoroughgoing in its application of emptiness in that it applies it not just to the self but also to all dharmas (phenomena). In answer to the above question, the aggregates not only do not provide a self either together or in part to an individual, but they themselves have no abiding substance or fixed nature. Each aggregate depends upon causes and conditions, which are also dependent on causes and conditions and so on ad infinitum. Emptiness in this teaching is the emptiness of any fixed nature or substance whatsoever. In response to the question as to who is saved, this teaching asserts that the bodhisattvas vow to save all sentient beings but do not cling to the idea that there are beings at all. It is all an empty show, but a show manifesting suffering or liberation depending upon the flow of causes and conditions. The question might then be asked: “How should bodhisattvas deal with causes and conditions if they know that they are all ultimately empty and have no basis, origin, or goal and no real self or entity abides anywhere?”

The Distinct Teaching — this corresponds to the Flower Garland Sūtra that is directed specifically to those who are firmly established bodhisattvas, so it is distinct from the teachings for śrāvakas. At this point, one needs to see that emptiness is not a dead-end but just the beginning. This requires an appreciation for contingent phenomena and thus the truth of provisional existence. While continuing to recognize that all things are empty, the bodhisattvas also see that this emptiness is not a blank void or nothingness. Rather, the lack of a fixed or independent nature is what allows all things to flow and move, change and grow, and ultimately interrelate so thoroughly that all things affect all other things like a web that quivers all at once when any one strand is touched. All things, all beings, are provisional manifestations of this interpenetrating dynamic process. Realizing this, bodhisattvas negate the negation of emptiness. They are free to reengage the world and appreciate all things without clinging or attachment. Gradually they realize the Middle Way that integrates peaceful detachment with compassionate involvement. Zhiyi called the empty, the provisional, and the Middle Way aspects of reality the threefold truth. In this teaching they are approached dialectically. Emptiness is the thesis, provisional existence is the antithesis, and the synthesis is the Middle Way. This is not the final teaching however, because an even greater integration lies ahead. Finally, one might ask: “If the tripiṭaka and shared teachings negate the self and all phenomena, and the distinct teaching negates that negation, is there any explicitly affirmative teaching in Buddhism at all?”

The Perfect Teaching — this corresponds to the Lotus Sūtra and the Nirvāṇa Sūtra and it is considered perfect or well rounded (the Chinese character used for this teaching holds both meanings) because it presents the integration of all three truths — the empty, the provisional, and the Middle Way — into a seamless whole. Each of these, if properly understood, immediately leads to an understanding of the other two in this teaching. For instance, what is empty is provisionally existent and therefore exemplifies the Middle Way. While the earlier teachings negate the world of birth and death through an analytical or intuitive approach to emptiness or negate a one-sided emptiness by affirming the provisional existence of all things; the perfect teaching affirms the total unity of the threefold truth of the empty, the provisional, and the Middle Way. In this teaching, the affirmative aspects of the earlier negations are made explicit. Negative and limiting aspects are emptied, positive and boundless phenomena are provisionally affirmed, and all manifests the liberation of the Middle Way. For instance, previously the vehicles of the śrāvakas and pratyekabuddhas (privately awakened ones) were condemned in favor of the bodhisattva vehicle, but now all the provisional vehicles are shown to be none other than the unfolding of the One Vehicle leading all to buddhahood. In previous teachings the historical Śākyamuni Buddha was shown to be a finite provisional manifestation of the cosmic principle of buddhahood that is sometimes personified as a cosmic buddha named Vairocana who is said to transcend birth or death. The Lotus Sūtra, however, portrays Śākyamuni Buddha himself as the one who reveals the unborn and deathless nature of buddhahood through his timeless spiritual presence and skillful activity. Previous teachings compared and contrasted the empty, the provisional and the Middle Way, but here the intrinsic unity of the freedom of emptiness, the creative responsiveness of the provisional, and the sublimity of the Middle Way is fully revealed.

Before Zhiyi there had been a lot of debate about the true meaning of the Buddha’s teachings due to the contradictions found between the various sūtras and commentaries coming from India. Starting in the late fifth century, various attempts were made to reconcile the many teachings that were being translated. By Zhiyi’s time there were the so-called three schools of the south and seven schools of the north that each presented a different system for classifying the sūtras. These were not schools in the sense of sects or monastic orders, but rather differing schools of thought propounded by different monks. These schools arranged the sūtras into such categories as sudden, gradual, and indeterminate. Many of these schools favored the Flower Garland Sūtra or the Nirvāṇa Sūtra as the ultimate teaching of the Buddha.

Zhiyi critiqued these systems and presented his own system in the Profound Meaning of the Lotus Sūtra of the five flavors and eight teachings that showed how the teaching and practice of the other sūtras all led up to the Lotus Sūtra as the definitive expression of the Buddha’s ultimate teaching. This is what Nichiren is referring to in the following passage of the Kaimoku-shō:

The Buddhist texts, however, created three sects in South China and seven sects in North China. The controversies among them were furious. In the end, they were defeated by [T’ien-t’ai] Chih-che in the Ch’en (Chi) and Sui (Zui) dynasties. Accordingly, the priests of the ten sects stopped quarreling and resumed their mission to save the people. (Murano 2000, p. 16)