This name change took place around the same time another Minamoto scion took the clan name Takeda.
Minamoto no Mitsuyuki
His great-grandfather won Kai Province during the Gosannen War.
Nanbu Mitsuyuki
nan (南): (Japanese) south
bu (部): (Japanese) division
The new clan name derived from the location of his estates in Kai Province.
Sources
- (Image Attribution) 663highland. \”Nanbu-jinja02s3200.\” Wikipedia. 24 August 2007. CC BY-SA 3.0.
- \”Nanbu-shi\” on Harimaya.com
- \”Nanbu clan.\” Wikipedia.