The Amakasu Incident (Amakasu jiken) was the murder of two prominent Japanese anarchists and a young boy by military police, led by Lieutenant Amakasu Masahiko, in September 1923. The victims were Ōsugi Sakae, an informal leader of the Japanese anarchist movement, together with the anarcha-feminist Itō Noe (his wife), and Ōsugi's child nephew.
Following the devastating Great Kantō earthquake in early September 1923, Japanese authorities massacred dissidents and ethnic Koreans in the Kantō Massacre in the subsequent chaos. Itō, Ōsugi, and his nephew were arrested on the 16th September. According to writer and activist Harumi Setouchi, Itō, Ōsugi, and his 6 year old nephew were arrested, beaten to death and thrown into an abandoned well by a squad of military police led by Lieutenant Masahiko Amakasu. According to literary scholar Patricia Morley, Itō and Ōsugi were strangled in their cells.
What both accounts agree on, however, is that both or all of the prisoners were brutally executed without even the formality of a trial, where conviction and death sentence would in the case of the two adults have probably been a foregone conclusion. This became known as the Amakasu Incident and it sparked much anger. The historian John Crump argued that "once again, the most able anarchist of his generation had been murdered," echoing the High Treason Incident just twelve years prior.
Following nationwide outcry, Amakasu was court-martialed and sentenced to 10 years in prison. When Hirohito became Emperor of Japan three years later, Amakasu was released. He studied in France and became a special agent for the Imperial Japanese Army in Manchuria. When Japan surrendered in August 1945 he killed himself with potassium cyanide.
- Crump, John (1993). Hatta Shūzō and Pure Anarchism in Interwar Japan. London: Palgrave Macmillan. p. 43. doi:10.1007/978-1-349-23038-9. ISBN 978-1-349-23040-2.
- Setouchi, Harumi (1993). Beauty in Disarray (1st ed.). Rutland, Vermont: Charles E. Tuttle Company. pp. 18–19. ISBN 0-8048-1866-5.
- Morley, Patricia (1999). The Mountain is Moving: Japanese Women's Lives. University of British Columbia Press. p. 19. ISBN 9780774806756.
- Cybriwsky, Roman (2011). Historical Dictionary of Tokyo. Scarecrow Press. p. 21. ISBN 978-0-8108-7489-3.