Like many detective fiction practitioners, Rampo also created a series based on one detective figure: Akechi Kogorō. This detective which has enjoyed long-lasting popularity up until now appears in 21 works that are oriented toward the adult reader, together with the Boy Detective Club series which are oriented toward children. “The Case of the Murder on D. Hill” (D-zaka satsujin jiken;「D坂殺人事件」) was the very first story featuring Akechi as an amateur detective.
Akechi was depicted as an eccentric, smart intellectual who looked like no more than 25-year-olds. He wore a loud, striped yukata that was unusual and stood out in the crowd, which in one aspect reflects his eccentricity. Rampo mentioned that Akechi’s appearance was largely taken from the crippled storyteller Kanda Hakuryū 神田伯龍（五代目） but with longer and more tangled hair .Footnote: