Understanding of the Musa sanjin in the Myōgyō shin’yōshū

Abstract

The term Musa sanjin 無作三身 indicating the idea that one does not obtain the three Buddha bodies through practice, but rather that one is originally awakened, was used by Saichō 最澄 when he explained that the reward body exists forever. But it started to be used as the theoretical basis by which we assume that all living things are really Buddha according to the idea of original enlightenment which developed after the mid-Heian period. The Myōgyō shin’yōshū 妙行心要集 is one of the oldest documents in which the meaning of Musa sanjin can be seen evolving, and so by considering its presentation, I conclude that this evolution underwent the influence of Yogācāra thought.