Because Ujikuni HOJO, a family member of the Gohojo clan, deprived the property of the Fujita clan, Nobuyoshi broke away from the Hojo clan and served as a vassal of Katsuyori TAKEDA.
藤田氏も後北条氏の一族北条氏邦に家督を奪われていたため、信吉は北条氏を離反し、武田勝頼の家臣として仕えた。