Ogasawara Nagamasa

Ogasawara Nagamasa was a Kamakura-period warrior and gokenin who succeeded his father Nagatada as head of the Ogasawara clan. Modern research holds that, far from ruling the family's Shinano lands, he may have held only an estate in Koma district, Kai Province, while the Tomono line controlled the Shinano holdings.

Appointed a councilor of the Rokuhara tandai, he appears to have been based in Kyoto. When the Tomono were destroyed in the Shimotsuki Incident of 1285, the clan's headship passed to his son Nagauji, ancestor of the later Shinano shugo house.