The territorial conquests of the Empire of Japan in the Western Pacific and East Asia regions began in 1895 with its victory over Qing China in the First Sino-Japanese War. Subsequent victories over the Russian and German Empires expanded Japanese rule to Taiwan, Korea, Micronesia, and southern Sakhalin. In 1931, Japan invaded Manchuria, resulting in the establishment of the puppet state of Manchukuo the following year; thereafter, Japan adopted a policy of founding and supporting puppet states in conquered regions. These conquered territories became the basis for the Greater East Asia Co-Prosperity Sphere in 1940.
Including the naichi, colonies, occupied territories, and puppet states, the Empire of Japan at its apex was one of the largest empires in history. The total amount of land under Japanese sovereignty reached 8,510,000 km2 (3,300,000 sq mi) in 1942. By 1943, it accounted for more than 20% of the world’s population at the time with 463 million people in its occupied regions and territories.
Colonial control over the far-flung territories from Tokyo ended after the Allies defeated Japan in 1945. The extent of Japanese governance was restricted to the naichi (excepting Karafuto Prefecture, which was annexed by the Soviet Union); the Nanpō and Ryūkyū Islands were returned to Japan in 1968 and 1972 respectively.
The first overseas territories that Japan acquired were the islands of its surrounding seas. During the early Meiji era, Japan established control over the Nanpō, Ryukyu, and Kuril Islands; it also strengthened control of the naichi. But this effort was less an initial step toward colonial expansion than it was a reassertion of national authority over territories traditionally within the Japanese cultural sphere.
At the start of the twentieth century the rate of population increase in Japan was seen as a potential problem for the Japanese government, and colonial expansion into Korea and Manchuria was seen as a possible solution.
Between 1895 and 1945, Taiwan, including the Pescadores, was a colony of the Empire of Japan; following the defeat of Qing China in the First Sino-Japanese War, it ceded Taiwan to Japan under the terms of the Treaty of Shimonoseki. The short-lived Republic of Formosa resistance movement was quickly suppressed by the Japanese military. The fall of Tainan ended organized resistance to Japanese occupation and inaugurated five decades of Japanese rule.
Since Taiwan was Japan’s first overseas colony, the central and colonial governments turned their efforts into making the island a “model colony”. These resulted in the modernization of the island’s economy, infrastructure, industry, public works, and assimilation of its population.
In 1945, after the defeat of the Empire of Japan in World War II, Taiwan was placed under the control of the Republic of China with the signing of the Japanese Instrument of Surrender. The experience of Japanese rule, Kuomintang rule, and the February 28 Incident (1947) continues to affect issues such as Retrocession Day, national and ethnic identity, and the Taiwan independence movement.