It is believed that, while he served in Shinano Province as Governor, he established Uenodaira-jo Castle in Ina County, Shinano Province, and that he established the foundation for his descendents to have political power over the Minamishinano region.
信濃守として任国に下向した際、同国伊那郡に上ノ平城を築城し、後に為公の後裔が南信濃に勢力を張る地盤を築いたと云われる。