It is believed that he was originally the Daikan (local governor) for the Hara clan, but he later used the Kogane region as his own base and built Otanikuchi-jo Castle (as known as Kogane-jo Castle).
当初は原氏の代官的な地位にあったと推定されるが、後に小金を自分の本拠として大谷口城（小金城）を築城したとされる。