Sakuma was born in Abu District, Nagato Province, as the younger son of Okamura Magoshichi, a samurai of Chōshū Domain, and was later adopted into the Sakuma family. He studied Western military science under Ōmura Masujirō and was a company commander defending the domain against the Second Chōshū expedition mounted by the Tokugawa shogunate in 1866. He subsequently served in the Boshin War of the Meiji restoration with distinction at the Battle of Aizu. In 1872, he entered the fledgling Imperial Japanese Army as a captain. In February 1874, Sakuma participated in the suppression of the Saga Rebellion, during which time he led a column of troops from Kumamoto Castle. He then participated in the Taiwan Expedition of 1874, where on May 22 he commanded the 150 strong force of soldiers that was ambushed by aborigines, initiating the Battle of Stone Gate. During the Satsuma Rebellion, he was commander of the IJA 6th Infantry Regiment. He was promoted to colonel in 1878. In February 1881, Sakuma was promoted to major general in command of the Sendaimilitary district. In May 1885, Sakuma was given command of the IJA 10th Infantry Brigade and promoted to lieutenant general the following year. The same year, 1886, he was elevated to the title of danshaku under the kazoku peerage system. With the outbreak of the First Sino-Japanese War, Sakuma commanded the IJA 2nd Division at the Battle of Weihaiwei, and later served as Japanese military governor of Weihaiwei in Shandong Province, China. At the end of the war, he was awarded the Grand Cordon of Order of the Rising Sun, and elevated to shishaku. In 1898, Sakuma was appointed commander of the central division of the Imperial Guardss, and became a full general. After a brief period on leave, he then became commander of the Tokyo Garrison. In April 1906, after his appointment as 5th Governor-General of Taiwan, Sakuma was awarded the Order of the Rising Sun, and in 1907 was elevated to hakushaku. With the end of armed resistance by Taiwan's Han Chinese population, the colonial authorities turned their attention to the suppression of the mountain dwelling aboriginal tribes. One of the reasons Sakuma was selected to head the colonial government was due to his participation in Japan's previous 1874 campaign, and his mission extended Japanese control into the aboriginal regions. During his tenure, Sakuma led several armed campaigns against the Atayal, Bunun and Truku peoples. Sakuma was one of the longest-serving governor-generals of Taiwan, stepping down in 1915, after having successfully completed his pacification campaign. He was highly regarded for helping develop Taiwan's east coast, especially the port of Hualien, and the Taroko Gorge area. He is also credited with introducing baseball to Taiwan in 1910. After his death, he became a kami under State Shinto, and a shrine was erected in his honor in Sagamihara, Kanagawa Prefecture, and in Taihoku. The shrine in Japan still exists, and unsuccessful efforts have been made to reconstruct the one in Taiwan as well.
