(There were cases in which the ceremonial investiture of the Crown Prince was not performed, like Emperor Koko, Emperor Goshirakawa, and Emperor Gohorikawa, before the Northern and Southern Dynasties, because they were enthroned suddenly.
（なお南北朝以前にも光孝天皇・後白河天皇・後堀河天皇などのように立太子されない例もあるが、いずれも急遽擁立された例である）。