Yoritomo arrived at Awa Province on September 27, 1180 (August 29, 1180 in old lunar calendar), he called on Hirotsune KAZUSA and Tsunetane CHIBA, who had influence in Boso Peninsula, for support and also sent Tokimasa HOJO to call on Nobuyoshi TAKEDA of Kai-Genji (Minamoto clan) for reinforcements.
治承4年（1180年）8月29日、安房国へ上陸した頼朝は、房総半島に勢力を持つ上総広常と千葉常胤に参上を命じ、北条時政を甲斐源氏の武田信義に加勢させるべく送る。