Futari Okajima is the pen name of two authors, Izumi Inoue (井上泉) and Junichi Tokuyama (徳山諄一). They have won the Edogawa Rampo Prize with 焦茶色のパステル and the Mystery Writers of Japan Award with チョコレートゲーム. Junichi Tokuyama mostly designed the plot while Izumi Inoue took care of the writing, but in the later period of their collaboration, Izumi Inoue participated more and more in the plot while still doing the writing.