When Yoshitune found out that the fox's real priority was Shizuka Gozen's Tsuzumi (a hand drum) made from the skin of its parent, he gave the fox his own name and allowed the fox to call himself "Genkuro".
狐の意中の物は、親の皮で出来た御前の鼓であったが、それを知った義経は、自分の名を与えて「源九郎」と名乗ることを許した。