On the 26th of August (Jishō calendar), Hatakeyama wanted to get back at the Miura for the Battle of Kotsubo, which he had lost.

He sent Shigeyori Kawagoe [jp] and Edo Shigenaga a message, telling them that they should gather an army from their provinces and come to meet him.

Soon after, in the hour of the rabbit (6:00), rumors of this mobilization spread to the Miura, and the entire family retreated, and set up camp in Kinugasa Castle.

[3] Exhausted from the previous battle in Kotsubo pass and running out of arrows, the Miura clan eventually abandoned Kinugasa Castle at night and escaped, heading for Awa Province to join Yoritomo's new call to arms,[1][3] after he had recovered from Ishibashiyama and his allies defeated the Taira at the Battle of Hashidayama.

[1][3] After the battle, the remaining Miura and Yoritomo forces regrouped into a large army, along with Chiba Tsunetane [jp] and Kazusa Hirotsune, the two major powers on the Bōsō Peninsula.

[7] Yoritomo told the present Miura forces not to hold grudges, or else the Minamoto clan will not achieve their goals.