上総国
In 1564, he took Kōnodai in Shimōsa Province following a battle against Satomi Yoshihiro (里見 義弘) (Battle of Kōnodai (1564)). Following this victory, Ujiyasu pushed on into Shimosa Province and Kazusa Province, but was never able to destroy the Satomi clan, who remained a thorn in the Hôjô's side right up until 1590.