The Ssu fen lü precepts had been formulated by the historical Buddha, Śākyamuni, in response to specific situations. The Fan wang precepts, in contrast, were said to be eternal and universal, the precepts of a thousand Buddhas. Saichō considered them to be the source from which all Buddhas and bodhisattvas proceeded. Moreover, they were based in the Buddha-nature which everyone possessed and thus were called the Busshōkai (Buddha-nature precepts). Everyone could and should follow these precepts. Holding the precepts made one a true disciple of the Buddha and allowed him to enter the ranks of the Buddhas. Thus the Fan wang precepts were considered to be the ultimate teaching, not a provisional one. The Fan wang precepts enabled the practitioner to enter the Direct Path (jikidō) to enlightenment without any danger of backsliding.

The Perfect precepts were much more than mere rules of conduct. All elements of the Perfect threefold learning were essentially expressions of the Buddha. They were grounded in one’s own inherently pure nature (jishō shōjō). Complete adherence to the precepts would result in complete mastery of meditation and wisdom. Perfect observance of the precepts in which the practitioner would never even be tempted to violate a rule would necessarily entail a profound understanding of the nonsubstantiality of all things. In such a case the practitioner’s observance of all three elements of the threefold learning would be immovable and unhindered (kokū fudō) by any obstacle.

[T]he precepts could be practiced by anyone. Even people who were too slow witted to understand doctrine or who did not have enough time to practice meditation could observe the precepts. Saichō repeatedly argued in the Kenkairon that the Fan wang precepts and the Anrakugyō [Peaceful Practices chapter of Lotus Sutra] were for everyone, including monks and nuns, laymen and laywomen. They could even be conferred between husband and wife. If people with Perfect faculties (enki) would follow Perfect practices, then they would be able to ameliorate the calamities which might befall the state. Conferring the Perfect precepts would protect the nation (denkai gokoku).

Saichō was clearly dissatisfied with the traditional T’ien-t’ai position that monks should be ordained with the Ssu fen lü precepts, but practice them with a Mahāyāna spirit. The precepts needed to be reformed as thoroughly as meditation and wisdom had been. For Saichō the Perfect threefold teaching consisted of the Fan wang precepts as the Perfect precepts, the four types of Tendai meditation (shishu sanmai) as Perfect meditation, and the study of the Perfect teachings expounded in such texts as the Lotus Sūtra as Perfect wisdom. By following Perfect practices Saichō claimed that “even a person with the dullest faculties would surely receive some sign (from the Buddha that his efforts were effective) after spending twelve years (on Mount Hie).”

Chinese T’ien-t’ai masters such as Chih-i and Chan-jan were more interested in meditation and doctrinal issues than in the precepts. In the Mo ho Chih kuan, Chih-i discussed the precepts as a preliminary practice for meditation, a position which was consistent with traditional theories of the threefold learning. He also applied the Tendai kaie (reveal and harmonize) mode of exegesis to the Ssu fen lü precepts in order to explain their significance for Mahāyāna practice. Chan-jan argued that the attitude of the practitioner, not the Hinayāna origin of the precepts, was the crucial factor in the interpretation of Ssu fen lü ordinations.

Saichō was deeply dissatisfied with these interpretations. Previous efforts to interpret the Ssu fen lü precepts as a form of Mahāyāna monastic discipline or to supplement them with the bodhisattva precepts were unconvincing to Saichō. What was needed, he argued, was a set of precepts which were exclusively Mahāyāna. He stated his position in the Kenkairon:

Although the ten major precepts (of the Fan wang Ching) have been transmitted before, this was in name only; their (true) meaning was not transmitted. How do I know that their (true) meaning was not transmitted? Because their Perfect meaning has not yet been understood and because they have been followed together with the Hinayāna precepts.

Saichō explained his reasons for stressing that the Fan wang precepts must be practiced without reference to the Ssu fen lü precepts in the following passage:

The monastic leaders (sōtō) state: The Lotus Sūtra teaches that one should not consort with anyone who seeks Hinayāna goals, but in Japan there are no monks who seek Hinayāna goals.

Saichō replies: Although (those who board) the sheep vehicle or elephant vehicle do not seek Hinayāna rewards, still they backslide to the realms of the two (Hinayāna) vehicles and take 80,000 kalpas to recover (and attain Buddhahood). Although no monks in this country seek Hinayāna goals, they do follow the Hinayāna rules of conduct and thus follow Hinayāna practices. How can this not lead to a Hinayāna result (in the end)?

What were the practices for the Perfect Teaching which enabled a person to follow the Direct Path to enlightenment? One of the earliest and most common classifications of Buddhist practice was the threefold learning (sangaku) or the practices of precepts, meditation, and wisdom. In Hinayāna Buddhism the threefold learning was usually regarded as a progression of practices which led to the final goal of liberation. The precepts provided the moral basis for meditation; meditation provided the basis for wisdom; and wisdom led to liberation. Although the precepts served as the basis for the entire structure, they were ranked lower than the other two types of learning.

The Chinese Ssu fen lü master Daoxuan (596-667) had used the classification of Buddhism into three types of learning to argue that the precepts were the basis of all Buddhist practice. He criticized the tendency of many Chinese monks to concentrate on meditation or lecturing on the sūtras (wisdom) while they ignored monastic discipline (precepts). Such one-sided practice could not succeed because it overlooked the most basic practice of all, the observance of the precepts.

Daoxuan also criticized monks who ignored the Ssu fen lü precepts because of their Hinayāna origins. These monks argued that they were Mahāyāna monks and should not be bound by Hinayāna precepts. Daoxuan defended the Ssu fen lü precepts by arguing that they were, in fact, partially Mahāyāna (buntsū daijō). T’ien-t’ai monks such as Chan-jan (711-782) noted that the attitude of the practitioner, not the origin of the precepts, determinined whether a person’s practice was Hinayāna or Mahāyāna. Thus T’ien-t’ai monks almost always advocated adherence to the Ssu fen lü precepts.

Saichō argued that Hinayāna and Hossō practices all required eons, but that the Japanese could not actually follow them because they were not suited to their faculties. In contrast, the Lotus Sūtra taught a direct path; instead of walking (hogyō) upon the path, the practitioner flew (higyō) directly to his goal. The path requiring eons was descriptive of Mahāyāna doctrines and practices ranging from those of the Sanron and Hossō Schools to those of the Kegon School. In the Hokke shūku, Saichō characterized the differences between Kegon and Tendai One-vehicle teachings in terms of their efficacy in leading to enlightenment. Kegon practice was described as leading to sudden enlightenment only after eons of training (ryakukō shugyō tongo). Kegon doctrines had not yet fully revealed the ultimate teaching of the Buddha, nor had they been purged of provisional teachings. The teachings of the Lotus Sūtra, however, led directly to sudden enlightenment (jikishi dōjō tongo). An adherent of the Lotus Sūtra had no need for eons of preparatory practice and provisional teachings.