He has composed songs for several artists, like AKB48, Hironobu Kageyama, Maho Suzuri, and Haruko Momoi. Masatoshi was worked as a day laborer at the Japan Break Industrial Company (日本ブレイク工業), a dismantling operator in Japan, and he has been known for composing and singing that company's song 日本ブレイク工業 社歌 in 2002. At that time, Masatoshi used his 萬Z(量産型) alias.