佐賀の乱
Following the establishment of the Imperial Japanese Army in 1872, Tani accepted the rank of major general. He became commander of the Kumamoto garrison the following year, and worked closely with Yamagata Aritomo to reform the army along French lines, over the opposition of Itagaki and Kirino Toshiaki, He personally led troops to suppress a number of "samurai" uprisings in Kyūshū, including the Saga Rebellion and Shimpūren Rebellion, and withstood a siege of 52 days in Kumamoto castle against Saigō Takamori during the Satsuma Rebellion.