Minamoto no Kunimasa (源国政)

MINAMOTO no Kunimasa (year of birth and death unknown) was a Busho (Japanese military commander) at the end of Heian period. He was the first son of MINAMOTO no Kuninao. His brothers included MINAMOTO no Kunimoto and MINAMOTO no Atsumitsu and his children included Kuninari HIDASE, Yorikiyo YAMAGATA, Kunitoki OCHIAI and Yorikane SHIMIZU. He called himself Yamagata sensei or Saburo YAMAGATA. He was also described as Kunimasa YAMAGATA.

He is understood to have been adopted to MINAMOTO no Yorimasa, his male cousin in the family tree. It is said that while he inherited Shoryo (territory) of Yamagata-gun, Mino-no-kuni (Gifu Prefecture) from his father, he served as Saiinshi no suke (Vice minister of Office of the High Priestess of Kamo-jinja Shrine) and so on in Kyoto and was promoted to Jugoinoge (Junior Fifth Rank, Lower Grade) ("Sonpi Bunmyaku", a text compiled in the fourteenth century that records the lineages of the aristocracy). Although the situation in details was unknown, there is a legend that the head of Yorimasa who killed himself during the Rising of Prince Mochihito was buried in the Mino territory of Kunimasa (present Renge-ji Temple, Seki City, Gifu Prefecture).

His four sons had their respective territories in Mino Province and exercised influence as Yamagata clan of Mino-Genji (Minamoto clan).