The Japan Self-Defence Forces are the unified military forces of Japan that were established in 1954, and are controlled by the Ministry of Defence.

In the novel number9dream, Eiji Miyake thinks about the Japan Self-Defence Forces while having coffee at the Jupiter Café in Tokyo. He is mentally preparing to go to PanOpticon to meet his father's lawyer, Akiko Katō, but he is nervous. He recalls that "a recruitment officer of the Self-Defence Forces came to my high school last year, and said that no fighting unit wants people who are immune to fear – soldiers who don't feel fear get their platoon killed in the first five minutes on the battlefield. A good soldier controls and uses his fear to sharpen his senses."