Like them, the Ishikawa clan of Mutsu Province including Takanobu ISHIKAWA belonged to another clan, the Nanbu clan of the Yoshimitsu line (Kai-Genji [the Minamoto clan of Kai Province) of Seiwa-Genji.
同じく、陸奥の石川高信の石川氏も清和源氏義光流（甲斐源氏）南部氏族。