Since then, Yoshitsune was called 'the son of Kamakura,' which means that he entered under the custody of Yoritomo as his adopted son, and as "Gyokuyo" describes, they were 'in a relation of father and son,' and therefore, Yoshitsune was thought to have a possibility to be the heir to Yoritomo (Yoritomo's legitimate son Yoriie had not been born at that time yet), and at the same time, he was meant to be placed in a subordinate position to Yoritomo.
以後、義経は「御曹司」と呼ばれるが、これは『玉葉』に両者は「父子之義」とあるように頼朝の養子としてその保護下に入ったことを意味し、場合によってはその後継者ともなり得る存在になった（当時、頼朝の嫡子頼家はまだ産まれていなかった）とともに、「父」頼朝に従属する立場に置かれたと考えられる。