Some people say that his too-long life and reign may have been brought by calculation methods such that a six-month period was counted as one year or the period of his reign included his father's period.
ただし、この長すぎる在位や高い年齢については半年を一年と数える半年暦や先代天皇との親子合算方式の在位年数を考慮すべきとの説もある。