South Seas Mandate in the context of "Imperial Japan"

The Empire of Japan, also known as the Japanese Empire or Imperial Japan, was the Japanese nation state that existed from the Meiji Restoration on January 3, 1868, until the Constitution of Japan took effect on May 3, 1947. From August 1910 to September 1945, it included the Japanese archipelago, the Kurils, Karafuto, Korea, and Taiwan. The South Seas Mandate and concessions such as the Kwantung Leased Territory were de jure not internal parts of the empire but dependent territories. In the closing stages of World War II, with Japan defeated alongside the rest of the Axis powers, the formalized surrender was issued on September 2, 1945, in compliance with the Potsdam Declaration of the Allies, and the empire's territory subsequently shrunk to cover only the Japanese archipelago resembling modern Japan.

Under the slogans of "Enrich the Country, Strengthen the Armed Forces" and "Promote Industry" which followed the Boshin War and the restoration of power to the emperor from the shogun, Japan underwent a period of large-scale industrialization and militarization, often regarded as the fastest modernization of any country to date. All of these aspects contributed to Japan's emergence as a great power following the First Sino-Japanese War, the Boxer Rebellion, the Russo-Japanese War, and World War I. Economic and political turmoil in the 1920s, including the Great Depression, led to the rise of militarism, nationalism, statism and authoritarianism, during which Japan joined the Axis alliance with Nazi Germany and Fascist Italy, conquering a large part of the Asia–Pacific; during this period, the Imperial Japanese Army (IJA) and the Imperial Japanese Navy (IJN) committed numerous atrocities and war crimes, including the Nanjing Massacre. There has been a debate over defining the political system of Japan as a dictatorship, which has been disputed due by the absence of a dictator, and over calling it fascist. The other suggested terms were para-fascism, militarism, corporatism, totalitarianism, and police state.

The colonial expansion of the Empire of Japan in the Western Pacific Ocean and East Asia began in 1895 with Japan's victory over the Chinese Qing dynasty in the First Sino-Japanese War. Subsequent victories over the Russian Empire (Russo-Japanese War of 1904-1905) and the German Empire (World War I) expanded Japanese rule. Taiwan came under Japanese control from 1895, Korea in 1905, Micronesia in 1914, Southern Sakhalin in 1905, several concessions in China from 1903 onwards, and the South Manchuria Railway from 1905. 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 what became known as the Greater East Asia Co-Prosperity Sphere from 1940. (The Co-Prosperity Sphere expanded to include much of China, Indo-China, Malaya, the Philippines, the East Indies, Burma and New Guinea by 1942.)

Including Mainland Japan, 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 km (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.

Saipan (/saɪˈpæn/) is the largest island and capital of the Northern Mariana Islands, an unincorporated territory of the United States in the western Pacific Ocean. According to 2020 estimates by the United States Census Bureau, the population of Saipan was 43,385. Its people have been United States citizens since the 1980s. Saipan is one of the main homes of the Chamorro, the indigenous people of the Mariana Islands.

From the 17th century, the island experienced Spanish occupation and rule until the Spanish–American War of 1898, when Saipan was briefly occupied by the United States, before being formally sold to Germany. About 15 years of German rule were followed by 30 years of Japanese rule, which was ended by the Battle of Saipan, as the United States began to take control of the Philippine Sea. Following World War II, Saipan became part of the Trust Territory of the Pacific Islands, and was administered by the United States, along with rest of the Northern Marianas. In 1978, Saipan formally joined the United States as part of the Commonwealth of the Northern Mariana Islands.

The Trust Territory of the Pacific Islands (TTPI) was a United Nations trust territory in Micronesia administered by the United States from 1947 to 1994. The Imperial Japanese South Seas Mandate had been seized by the US during the Pacific War, as Japan had administered the territory since the League of Nations gave Japan a mandate over the area from Imperial Germany after World War I. However, in the 1930s, Japan left the League of Nations and invaded additional lands. During World War II, military control of the islands was contested, but by the war's end, the islands had come under the Allies' control. The Trust Territory of the Pacific was created to administer the islands as part of the United States while still under the auspices of the United Nations. Most of the island groups in the territory became independent states, with some degree of association kept with the United States: the Federated States of Micronesia, the Republic of the Marshall Islands and Palau are independent states in a Compact of Free Association with the US, while the Northern Mariana Islands remain under US jurisdiction, as an unincorporated territory and commonwealth.

"Mainland Japan" (内地, naichi; lit. '"inner lands"') is a term used to distinguish Japan's core land area from its outlying territories. "Mainland Japan" was an official term in the pre-war period, distinguishing Japan proper from its overseas territories (外地, gaichi, lit. "outer lands") in the Far East, such as Japanese Taiwan, Japanese Korea, Karafuto, the South Seas Mandate, and the Kwantung Leased Territory. After the end of World War II, its usage became less common and lost its previous legal significance.

The term's literal Japanese meaning might best be translated as "inner Japan" or "inner lands". The term "mainland" is somewhat inaccurate since it usually refers to all or part of a continental landmass, rather than islands. In the pre-1945 period, the "inner lands" included the Japanese archipelago, itself including the Ryukyu Islands and other island chains to the south of Honshu. The "inner lands" also referred during 1875–1945 to the Japanese-controlled Kuril Islands and during 1943–1945 to Karafuto, the southern half of the island of Sakhalin.