He received the title of Prince by Imperial order when he was seven months and eleven days old (two years old by counting in the old Japanese way) and became Crown Prince, he then succeeded to the throne on the same day. (the youngest Emperor in the history)
生後7ヶ月と11日（数え年で2歳）で親王宣下・立太子し、その日のうちに践祚（歴代最年少即位）。