Ichiman

was the eldest son of the 2nd Kamakura shōgun Minamoto no Yoriie. His mother, Wakasa no Tsubone, was Hiki Yoshikazu's daughter, and the child was brought up by the Hiki clan. A year after he was born, his grandfather, Minamoto no Yoritomo, died. To avoid power falling into the hands of the Hiki clan, the Hōjō decided to get rid of the Hiki clan and their protégé.

On a pretext, regent Hōjō Tokimasa invited Hiki Yoshikazu to his home and assassinated him. A battle between the clans ensued; the Hiki were defeated by a coalition of the Hōjō, Wada, Miura and Hatakeyama clans and exterminated. Six-year-old Ichiman also died during the fight. The Hiki residence was destroyed by fire and in its place in the Hikigayatsu valley now lies the Buddhist temple of Myōhon-ji. In its cemetery still stands Ichiman's grave, next to the Hiki clan's cenotaph.

Ichiman's younger brother Kugyō was forced to become a Buddhist priest, and in 1219, he assassinated his uncle, Minamoto no Sanetomo. Kugyō was himself immediately executed for his crime, thus bringing the Minamoto clan to a sudden end.