In Nihonshoki, all years, months and dates were written in the Oriental zodiac, and it is recorded that the date of his enthronement was "kanototorinotoshi harusyogatsu kanoetatunotuitachi."
『日本書紀』は年月日は全て干支で記しており、即位年月日は「辛酉年春正月庚辰朔」とある。