Yoritomo created his base and capital at Kamakura, in Izu. Hōjō Tokimasa became his de facto advisor. The Genpei War between Minamoto and Taira had begun. In 1181, Taira no Kiyomori died, leaving the Taira family in the hands of Taira no Munemori, his son and a hothead who had no knowledge of military matters. In 1182, Tokimasa's son, Yoshitoki, wed. That same year, Masako and Yoritomo had a son, Minamoto no Yoriie, Yoritomo's heir. This would also become Tokimasa's first male grandchild. The next year, Yoshitoki and his wife had their first child, a son, Hōjō Yasutoki, who would become heir to the Hōjō after Yoshitoki's death.