In the Battle of Mikatagahara (in 1572), Nobumori, together with Hirohide HIRATE, reinforced the 8,000 soldiers of Ieyasu TOKUGAWA with another 3,000 men, but he retreated without hardly any fighting as soon as he saw the 27,000 troops of the Takeda clan.
元亀3年（1572年）の三方ヶ原の戦いでは、平手汎秀と共に3,000の兵を率い、徳川家康8,000の援軍に赴くも、信盛は27,000の武田氏を目の当たりにし、ほとんど戦わずして退却。