Japanese interest in what it called the began in the 19th century, prior to its imperial expansion into
Korea and
China. By 1875, ships from the newly established
Imperial Japanese Navy (IJN) began to hold training missions in the area.
Shiga Shigetaka, a writer who accompanied a Navy cruise to the region in 1886, published his in 1887, marking the first time a Japanese civilian published a firsthand account of Micronesia. Three years later, Shiga advocated for annexation of the area by claiming that doing so would "excite an expeditionary spirit in the demoralized Japanese race." Despite the appeal imperialism had for the Japanese public at the time, neither the
Meiji government nor the Navy seized any pretexts to fulfill this popular aspiration. It was through the commercial operations of fisherman and traders that the Japanese first began to make a wider presence in the region, which continued to grow despite challenges from competing German commercial interests. Although the Japanese public's enthusiasm for southward expansion had abated by the turn of the century, a number of important intellectuals, businessmen, and military officials continued to advocate for it. Among them were Admiral
Satō Tetsutarō and
Diet member
Takekoshi Yosaburō. The latter declared that the future of Japan "lies not in the north, but in the south, not on the continent, but on the ocean" and that its "great task" was to "turn the Pacific into a Japanese lake." By the outbreak of
World War I the empire included
Taiwan,
Korea, the
Ryukyu Islands, the southern half of
Sakhalin island (
Karafuto Prefecture), the
Kuril Islands, and
Port Arthur (
Kwantung Leased Territory). The policy of
Nanshin-ron ("Southern Expansion Doctrine"), popular with the IJN, held that
Southeast Asia and the
Pacific Islands were the area of greatest potential value to the Japanese Empire for economic and territorial expansion. The
Anglo-Japanese Alliance of 1902 had been signed primarily to serve Britain's and Japan's common interest of opposing Russian expansion. Amongst other provisions the treaty called on each party to support the other in a war against more than one power, although it did not require a signatory state to go to war to aid the other. Within hours of Britain's declaration of war on Germany in 1914, Japan invoked the treaty and offered to declare war on the
German Empire if it could take German territories in China and the South Pacific. The British government officially asked Japan for assistance in destroying the raiders from the
Imperial German Navy in and around Chinese waters, and Japan sent Germany an ultimatum demanding that it vacate China and the
Marshall,
Marianas and
Caroline Islands. The ultimatum went unanswered and Japan formally declared war on Germany on 23 August 1914. and protection of the shipping lanes for
Allied commerce in the Pacific and
Indian Oceans. During the course of this operation, the Japanese Navy seized the German possessions in the Marianas, Carolines, Marshall Islands and
Palau groups by October 1914. After the end of World War I, the protectorate of German New Guinea was divided amongst the war's victors by the
Treaty of Versailles. The southern part of the protectorate was mandated to come under Australian administration as the
Territory of New Guinea, consisting of
Kaiser-Wilhelmsland (the German territory on the island of
New Guinea) and the German-controlled islands south of the equator. Meanwhile, Japanese occupation of the northern part of the protectorate, consisting of the
Micronesian islands north of the
equator, was formally recognized by the treaty. Japan was given a
League of Nations Class C mandate to govern them, the C Class being assigned because the Mandates Commission regarded the islands as having "low cultural, economic and political development". The terms of the Mandate specified that the islands should be demilitarized and Japan should not extend its influence further into the Pacific. The Mandate was initially subject to yearly scrutiny by the
Permanent Mandates Commission of the League of Nations in
Geneva, As there was no legal requirement for Japan to be a League member for it to have a mandate over the islands, it continued to administer them and submitted annual reports to the League until the outbreak of
World War II. The idea of reassigning the mandate was considered by the League and the
great powers but proved to be impractical. == Administration ==