The Takeda family, which is later to become the central force in the Kai-Genji clan, reportedly had the name first claimed by his father Yoshikiyo in Hitachi Province (according to "The History of Katsuta City" by Junichi SHIDA, although there is room for further study) and was used by Kiyomitsu's son Nobuyoshi, the founder of Kai-Takeda clan, to mark his genpuku, the attainment of manhood ceremony, which was held at Takeda Hachimangu Shrine (Nirasaki City, Yamanashi Prefecture).
武田氏は後に甲斐源氏の中心氏族となるが、武田姓の名乗りに関しては父の義清は常陸国において既に名乗っていたと言われ（志田諄一『勝田市史』、検討の余地も指摘される）、甲斐武田氏の祖となる清光の子信義が武田八幡宮（山梨県韮崎市）において元服した際に称したと言われる。