In "Heiji Monogatari" it was described that he was called HIRAGA Shiro Yoshinobu and that Yoshitomo who saw Yoshinobu fighting in the battle at the Sanjo-gawara ordered roto (retainer) to relieve him saying 'Oh, there is no stupid warrior among Minamoto clan even in the Muchisashi class (a retainer who follows his master with a whip). Doesn't make a valuable soldier, Hiraga, killed.'
『平治物語』には平賀四郎義宣と記され、三条河原での戦いで奮戦する義宣（義信）を見た義朝が、「あぱれ、源氏は鞭さしまでも、をろかなる者はなき物かな。あたら兵、平賀うたすな。」と郎党達に救うように命じている様が記載されている。