Born June 9, 1952 in Shizuoka Prefecture, Totsuka Osamu is a pianist, keyboardist, composer, and arranger. He studied at Keio University's Department of Politics before pursuing music seriously, training under Hayashi Masahiko, Kitagawa Yuu, Watanabe Sadao, and Fujii Sadayasu.

He's best known for his early work in the '70s arranging for J-pop singer Yagami Junko, with whom he created the hit "Omoida wa Utsukushisugite." Later, throughout the '90s, Totsuka worked as an accompanist and collaborator with various chanteuses and jazz singers, including Graciela Susana, Amano Noriko, and Katou Kunihiko.

He's a member of the Japan Composers & Arrangers Association (JCAA) and holds regular membership in the Japanese Society for Rights of Authors, Composers and Publishers (JASRAC).