SAMUKAWA no Ama's visit to Yoritomo led the armed groups belonging to the Oyama clan holding the fort to take Yoritomo's side because of the custom in those days: while the family head is away, his wife is authorized to handle all affairs of the clan.
夫の不在中は妻が権限を持つのが慣習であり、これによって在地にあった小山氏の武士団は頼朝方に立つ事になる。