太上皇
The incident was originally viewed as having been precipitated by Kusuko herself, and thus was called the "Kusuko Incident". In recent years, the view that the incident was caused by the division of power between the emperor of Japan and retired emperor under the Ritsuryō system has taken root. Since 2003, some Japanese high school textbooks have begun to refer to the incident as the "Retired Emperor Heizei Incident".