There is a dominant theory which states that he was born in 684, but there is another theory which states that he was born in 676 based on the articles of Kaifusou (Fond Recollections of Poetry).
天武天皇13年（684年）誕生説が有力であるが、懐風藻の記事にもとづき天武天皇5年（676年）とする説もある。