Seiwa had six sons who bore the surname Minamoto - a name granted as an honor by the Imperial court. The Seiwa Genji - including first Kamakura shogun Minamoto no Yoritomo and his brother, the famous Minamoto no Yoshitsune - claimed descent from Seiwa's sixth son, Minamoto no Sadazumi, through Sadazumi's son Minamoto no Tsunemoto.
|Emperor of Japan
- Karl Friday, Samurai Warfare and the State in Early Medieval Japan, Routledge (2004), 9.
- Evelyn Rawski, Early Modern China and Northeast Asia: Cross-Border Perspectives, Cambridge University Press (2015), 155.