In 1550, when he was a senior vassal of the Shiomatsu Ishibashi clan, he took over the reins of his lord, Hisayoshi ISHIBASHI by confining him in Ninomaru (outer citadel) of Shiomatsu-jo Castle.
当初は塩松石橋氏の重臣であったが、天文(日本)11年（1550年）に主君の石橋尚義を塩松城二の丸に幽閉して石橋氏の実権を掌握した。