It is said that the reason was that Toshihisa had no child of his own, and that because he had a sickly constitution, he was in the situation that "it is rather a long time since he served as a musha (warrior) last" (Memoranda of Shigeyori MURAI).
理由は利久に実子がなく、病弱のため「武者道少御無沙汰」の状態にあったからだという（村井重頼覚書）。