On June 4, 1244, Yasutsuna attended as a member of Council of State for the coming-of-age ceremony of FUJIWARA no Yoritsugu, who was a successor to the Shogun family, and offered Yoritsugu a cup of sake.
1244年6月4日（寛元2年4月21日(旧暦)）－将軍家の嫡子である藤原頼嗣の元服式に評定衆として参列、献杯する。