Minamoto no Ichiman (源 一幡, 1198 – October 8, 1203) was the eldest son of the 2nd Kamakura shōgun Minamoto no Yoriie.^[1] 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.^[1] The child was murdered at the age of 6. His father would later be murdered a year later.

When in 1203 Yoriie became seriously ill, the Hōjō clan supported his brother Senman (future third shōgun Minamoto no Sanetomo) as a future successor, while the Hiki supported son Ichiman.^[1][2] To avoid power falling into the hands of the Hiki clan, the Hōjō decided to get rid of the Hiki clan and their protégé.^[1]

On a pretext, Hōjō Tokimasa invited Hiki Yoshikazu to his home and assassinated him.^[1] A battle between the clans ensued; the Hiki were defeated by a coalition of the Hōjō, Wada, Miura and Hatakeyama clans and exterminated.^[1] Six-year-old Ichiman also died during the fight.^[1] 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.