Born in 1947, he is a graduate of the Tokyo University of Fine Arts and Music, winner of the Grand Prix at the Geneva International Composition Competition for Opera and Ballet, a Special Prize for Performing Arts from the Japan Agency for Cultural Affairs, and commissions from NHK, the National Theater, Suntory, Min-On, the City of Kyoto, and Salford College (U.K.). His orchestral works have been performed in Japan by the NHK Symphony Orchestra and others, and overseas by the Suisse Romande, Netherlands Radio, BBC Scottish, Radio France, Berlin, and Nurenberg. Niimi is currently a lecturer at the Toho Gakuen School of Music in Tokyo, and a member of the Board of Directors for the Japan Federation of Composers.