FUJIWARA no Motonari (a brother of FUJIWARA no Nobuyori, a boss of Yoshitomo, Yoshitsune's father. His daughter gave birth to FUJIWAWA no Yasuhira), who was Hidehira's father-in-law, was a son of FUJIWARA no Tadataka, who was the maternal cousin of Naganari so that they were relatives.
秀衡の舅である藤原基成（義経の父義朝の上司藤原信頼の弟。娘が藤原泰衡を生む）は、長成の母方の従兄弟にあたる藤原忠隆の子であり、親戚関係にあった。