Created by Kyotaro Nishimura, 30-year-old Inspector Shozo Totsugawa (十津川省三) first appeared in 赤い帆船 (1973). Later promoted Chief Inspector, Totsugawa is often paired with detective Sadao Kamei (亀井定雄). Even though he appeared in other novels as well, Totsugawa is mainly associated with the railway mystery novels, a series of murder mysteries where the stations and trains are the main setting.