The founder of the Suino family was Motokuni (or Nagakane) HIRATA, a son of NAKAHARA no Sukeyasu (the younger brother of KIYOHARA no Yorinari, an adopted son of NAKAHARA no Moromoto).
中原祐安（清原頼業弟・中原師元養子）の子・平田職国（長兼）を祖とする。