Some of family trees made according to this theory have a description which says that Norinaga's grandfather Shigenori served Yoritomo MINAMOTO, and because of his great achievement, he was appointed Jito shiki (manager and lord of a private estate) in Kojima, Bizen Province.
この説の流れを汲んだ系図には、範長の祖父・重範は源頼朝に従い、功があって備前国児島の地頭職に就いたと記述されたものもある。