According to the genealogy in "Sonpi Bunmyaku (a Japanese genealogical text)"Kagemasa was the descendant of TAIRA no Yoshishige who was the youngest son of TAIRA no Takamochi or TAIRA no Yoshikane, the second son in the fourth generation; also the text says that Kageyoshi Oba, Kagechika Oba and Kagetoki KAJIWARA were all descendants of Kagemasa in the third generation.
『尊卑分脈』による系譜では、景政を平高望の末子平良茂もしくは次男平良兼の4世孫とし、大庭景義・大庭景親・梶原景時らはいずれも景政の3世孫とする。