Kosakai Mitsuji (Japanese: 小酒井 光次, 8 October 1890 – 1 April 1929), better known by the pen name Kosakai Fuboku (Japanese: 小酒井 不木), was a Japanese medical scientist and crime writer. A variant of the family name Kosakai is Kozakai.
Source: “Kosakai Fuboku”, English Wikipedia (CC BY-SA 4.0), excerpt