After the war, Moroi served in several positions. He served as a member of the Social Education Agency in the Ministry of Education, as the head of the Tokyo Metropolitan Symphony Orchestra, and as Dean of Senzoku Gakuen University of Music. At the same time, he also worked on the dissemination of logical and constructive compositions through writing and education. He wrote several books including “Functional Harmony” and “Musical Studies”. His students include Yoshirō Irino, Akio Yashiro, Ikuma Dan and Minao Shibata. Although he couldn’t compose a lot during this period, he continued to have a willingness to compose. In the “Symphony No. 4” (1951), he used Russian music for his musical material. In “Piano concerto No. 2” (1977) composed in his last year, he used the technique of twelve-tone music. He died at the age of 73 in 1977.
