Kazusa was a province of ancient Japan which is now the south-central part of Chiba Prefecture. It was held by several clans, including the Kazusa-Takeda, Sakai, Toki, and Awamasaki (under Satomi) Clans. Later the Takeda, Sakai, and Toki Clans submitted to the Houjou Clan, which continued fighting fierce battles with the Satomi Clan.