descended from Seiwa Genji.
The Satomi claimed descent from the Seiwa Genji clan via Nitta Yoshishige (d. 1202), whose son Yoshitoshi took "Satomi" as his surname.
https://en.m.wikipedia.org/wiki/Satomi_clan
Home province
- Kōzuke Province, Awa Province
Retainers to the 大久保氏 Ōkubo clan