Ryuson was appointed Risshi (the second highest grade that can be held by one who has reached the third highest rank in the hierarchy of Buddhist priests) in 751, and on the occasion of the ceremony to consecrate the Great Buddha at Todai-ji Temple in 752, he acted as Kegon Lecturer, but he resigned the position of Risshi in 755.
751年（天平勝宝3年）律師に任じられ、翌752年（天平勝宝4年）の東大寺大仏開眼供養では華厳講師をつとめたが、755年（天平勝宝7年）律師を辞任している。