Nobukiyo was a grandson of Nobukoto OISHI, a younger brother of Yoshikatsu OISHI, who was a great-grandfather of Yoshio OISHI, that is, Nobukiyo belonged to a branch family of the Oishi clan.
信清は、大石良雄の曽祖父大石良勝の弟大石信云の孫にあたり、要するに信清は大石家の分家である。