Saichō’s view of the Perfect faculties of the Japanese people was partly based on statements in the Lotus Sūtra that the Buddha’s supreme teaching could be preached during the “latter evil age.” Saichō believed that the faculties of the Japanese people had matured and that they were ready to hear him expound the Buddha’s ultimate teaching found in the Lotus Sūtra. Although the Sanron and Hossō interpretations of the Lotus Sūtra had been studied previously in Japan, Saichō argued that they did not represent the correct interpretation of the Lotus Sūtra. The Tendai teachings concerning the Lotus Sūtra, transmitted directly to Saichō by Chinese T’ien-t’ai masters, were the only explanations of the sūtra which fully revealed it as the Buddha’s ultimate teaching. In order to stress this point, Saichō often referred to his school as the Tendai Hokkeshū (Lotus School), and thus closely linked the terms Tendai and Lotus Sūtra.

Chien-chen had brought the first T’ien-t’ai texts to Japan, but had not actively attempted to spread Tien-t’ai teachings. Instead, he had devoted himself to conducting Ssufen lü ordinations. As a result T’ien t’ai teachings were virtually forgotten several decades after Chien-chen’s death. In contrast, Saichō succeeded in spreading T’ien-t’ai teachings throughout Japan. By Saichō’s time the faculties of the Japanese people had matured. They were ready to listen to the Tendai interpretation of the Lotus Sūtra.