1. Concerning Zhiyi’s 智顗 theory of practice, the conventional view is that there was a turn from chan 禅 to zhiguan 止観. This is based on the view of Shindai Sekiguchi 関口真大, but there are two problems.
2. The first point is that he viewed the transition from chan to zhiguan as a “turning point.” Considering Zhiyi’s theory of practice, it is possible to contrast the chan in his youth with the zhiguan of his later years, but this should be recognized as a development, not a turn from chan to zhiguan. Certainly it is possible to confirm a strong awareness of the problems of “Chan masters” at that time, but as long as chan itself as a theory of practice is not denied, zhiguan should be considered as an extension of chan. The directions of chan and zhiguan are by no means different.
3. The second point is that Zhiyi’s theory of practice is based solely on three texts: the Shi chan boluomi cidi famen 釈禅波羅蜜次第法門 （T. 1916）, Tiantai xiao zhiguan 天台小止観 （T. 1915）, and Mohe zhiguan 摩訶止観 （T. 1911）. There are various discourses in common between the Shi chan boluomi cidi famen and Mohe zhiguan, as well as the Tiantai xiao zhiguan. In all of them, there is a common attitude of trying to summarize all the Buddha Dharma with a specific concept. Taking them all together, it is clear that the development from chan to zhiguan did not take place suddenly. Therefore, it would be inadequate to simply assume that Zhiyi’s theory of practice began with chan and culminated in zhiguan. Both chan and zhiguan need to be considered in the context of an attempt to summarize all the Buddha Dharma through a single word.
