Birth year of 1082: it is described that Yoshikuni was 18 when Yoshitada died, according to 'Nitta Ashikaga Ryo-kakeizu' (genealogies of both Nitta and Ashikaga families) owned by Ashikaga Banna-ji Temple.
永保2（1082年）説　足利鑁阿寺所蔵の「新田足利両家系図」に、義忠没時の義国の年齢を18歳と記している。