Tadaaki fought with Takauji, who had returned to Kyoto with an army he had formed in Kyushu, but was defeated and killed by Tadayoshi ASHIKAGA's forces in Nishi Sakamoto, Omi Province (Otsu City, Shiga Prefecture).
九州で勢力を整えて翌年に再び京都へ迫った足利方と戦い、近江国西坂本（滋賀県大津市）で足利直義の軍に敗れ戦死する。