Ryucho ISHII, an adopted child of Rikisaburo held positions such as Director of Interior Bureau, Taiwan Sotoku-fu, Director of Industry Bureau, Taiwan Sotoku-fu, Taipei City Governor, Tainan-shu Prefectural Governor.
力三郎の養子石井龍猪は、台湾総督府内務局長、殖産局長、台北市長、台南州知事等を歴任している。