With the act, Itagaki intended to gain support from Kai people, by reminding them that he was a member of the Inui clan succeeding the Itagaki clan that derived from Kai-Genji (Minamoto clan).
甲斐源氏の流れを汲む板垣氏の後継であるとの乾氏を示して甲斐国の民衆の支持を得るためである。