Generally, confronted by the many diverse schools of Buddhist thought from India, Chinese Buddhist thinkers tried to synthesize the various teachings into a comprehensive system.
And so, Zhiyi accordingly said that the Buddha’s four methods of teaching corresponded to four Buddhist doctrines, each geared towards a different kind of audience. They were:
(1) The Tripitaka Teaching: sutra or scripture, vinaya or monastic rules, and Abhidamma, the basic teachings. These correspond to the essential Theravada doctrine.
In this first kind of teaching, one renounces the everyday world and aims for nirvana. At this level of understanding, people are only interested in their own salvation.