Mitsuo Terada (寺田 光男, born October 29, 1968), known by his stage name Tsunku (つんく, often written as つんく♂), is a Japanese record producer, songwriter, and vocalist. He is known for being very prolific. Total sales of the singles he has written exceed 37.9 million copies, making him the fifth best-selling lyricist in Japan.
Tsunku is best known for having two major roles in the Japanese music landscape: first as the lead singer of the popular rock group Sharam Q, and now as the producer, primary composer, lyricist, and (until 2014) primary studio backing vocalist for highly popular idol group Morning Musume, in addition to Aya Matsuura and other associated idols under the Hello! Project banner, for whom he has written and produced the vast majority of their chart-topping hits. He has also produced music for other Japanese artists, including Ayumi Hamasaki's first number one single. As his musical influences he cites The Beatles, Japanese popular music (especially kayōkyoku), American and European hits being played on the radio when he was a schoolboy, disco acts such as Chic, Kool & the Gang and Earth, Wind & Fire, and bands like Duran Duran and The Power Station. He is mostly known outside of Japan for creating the Nintendo video game series Rhythm Tengoku/Rhythm Heaven.