The Fan wang precepts could not be understood as Perfect precepts until they had been interpreted according to the teachings of the Lotus Sūtra and the Tendai School. Such a view is not surprising since Saichō was defending the Lotus Sūtra in works such as the Shugo kokkaishō at the same time he was composing the Kenkairon. Saichō emphasized the role of the Lotus Sūtra by naming Śākyamuni Buddha the preceptor in the ordination ceremony and by asserting that the Ryōzen lineage was valid for the precepts. Five years after his death, Saichō’s disciples constructed a precepts platform with Śākyamuni and a Tahōtō (stūpa for Prabhūtaratna Tathāgata) occupying the central places on it.

The Fan wang Ching played the key role in the practice and interpretation of the Perfect precepts. However, the interpretation of the precepts was not complete until the Perfect sense of the Lotus Sūtra had been applied to them. This did not mean, however, that the Fan wang Ching could be ignored. Rather the Fan wang Ching specified the contents of the precepts. Saichō did not elaborate on the relative value of the two sūtras because he believed that the two texts contained Perfect teachings preached by Buddhas who were essentially the same. Elements from the Lotus Sūtra and its capping sūtra, the Kuan p’u hsien Ching, could be harmoniously combined with precepts from the Fan wang Ching because the Perfect purport of all three works was the same.