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)