In 2006 and 2007, Nishimura released two consecutive photo books, "Gekkan Rika 1" and "Gekkan Rika 2" (Monthly Rika 1 and 2). These books further solidified her reputation as a photographer who pushes the boundaries of self-representation and introspection. The images in these books showcase Nishimura's versatility and creativity, as she adopts different characters and scenarios, often incorporating elements of fantasy and surrealism.