While his father Yoshimitsu was establishing his power in Hitachi Province, he was assigned to control Takeda-go (Takeda village) in the province (Takeda, Hitachinaka City, Ibaraki Prefecture) and called himself 'Takeda Kaja.'
父の義光が常陸国に勢力を扶植する過程で、同国武田郷（茨城県ひたちなか市武田）の支配を任され「武田冠者」を名乗る。