OtsuichiOtsuichi.

Otsuichi (乙一, Otsuichi) is the pen name of Hirotaka Adachi (安達 寛高, Adachi Hirotaka; born October 21, 1978), a Japanese writer and filmmaker. He is a member of the Mystery Writers of Japan and the Honkaku Mystery Writers Club of Japan. He made his debut with Summer, Fireworks and My Corpse while still in high school.