Yasuhiro Kasamatsu was born in 1960 in Fukui. Graduated from Tokyo University, Faculty of Literature, majored in aesthetics and philosophy and started the activity as classical music composer. His String Quartet No,4 was given the first performance by the Vienna string quartet and highly estimated. Besides classical works, composed a lot of music for theater performances and dances. Especially the collaboration with the director Ninagawa Yukio has won high estimation and several prizes in Japan and Europe. These days, especially concentrated on composing the works for music and words, including chamber opera "Elektra Trilogy", committed by Oji hall.