Sasaki Nariyori(佐々木 成頼) (976-1003) was the progenitor of the Sasaki clan, having taken the name from his domain in Ōmi Province. He was the great-grandson of Minamoto no Masanobu, progenitor of the Uda Genji.
References
Papinot, Edmond (1910). Historical and geographical dictionary of Japan. Tokyo: Librarie Sansaisha.