South Seas Mandate
The South Seas Mandate, officially the Mandate for the German Possessions in the Pacific Ocean Lying North of the Equator,[2] was a League of Nations mandate in the "South Seas" given to the Empire of Japan by the League of Nations following World War I. The mandate consisted of islands in the north Pacific Ocean that had been part of German New Guinea within the German colonial empire until they were occupied by Japan during World War I. Japan governed the islands under the mandate as part of the Japanese colonial empire until World War II, when the United States captured the islands. The islands then became the United Nations–established Trust Territory of the Pacific Islands governed by the United States. The islands are now part of Palau, the Northern Mariana Islands, the Federated States of Micronesia, and the Marshall Islands.[3]
Not to be confused with Trust Territory of the Pacific Islands.
Japanese Mandate for the Governance of the South Seas Islands
Mandate of the League of Nations (colony) under Japanese administration
Japanese (official)
Austronesian languages
28 June 1919
18 July 1947
In Japan, the territory is known as "Japanese Mandate for the Governance of the South Seas Islands" (委任統治地域南洋群島, Nippon Inin Tōchi-ryō Nan'yō Guntō)[4] and was governed by the Nan'yō Government (南洋廳, Nan'yō-chō).
Significance[edit]
The population of the South Seas Mandate was too small to provide significant markets and the indigenous people had very limited financial resources for the purchase of imported goods. The major significance of the territory to the Empire of Japan was its strategic location, which dominated sea lanes across the Pacific Ocean and provided convenient provisioning locations for sailing vessels in need of water, fresh fruit, vegetables and meat.
As a signatory of the 1922 Washington Naval Treaty, Japan agreed not to build new naval and air stations on the islands and it did not begin direct military preparations in the Mandate until the late 1930s.[25] Nevertheless, the territory provided important coaling stations for steam-powered vessels[26] and its possession gave an impetus to the Nanshin-ron doctrine of "southward advance".[25]
The terms of the mandate required Japan not to fortify the islands. However, these terms were ambiguous and poorly-defined, specifying only that Japan should not build "fortifications" or construct "military or naval bases". From 1921 the Japanese military began making surveys and plans so that rapid military deployment to the islands would be possible in case of war.[31]
During the 1930s, the IJN began construction of airfields, fortifications, ports, and other military projects in the islands controlled under the mandate,[20][40] viewing the islands as "unsinkable aircraft carriers" with a critical role to play in the defense of the Japanese home islands against potential US invasion. These became important staging grounds for Japanese air and naval offensives in the Pacific War.[40][45]
The Imperial Japanese Army also utilized the islands to support air and land detachments.
In order to capture the islands from Japan, the United States military employed a "leapfrogging" strategy which involved conducting amphibious assaults on selected Japanese island fortresses, subjecting some to air attack only and entirely skipping over others.[47] This strategy caused the Japanese Empire to lose control of its Pacific possessions between 1943 and 1945.[48]
The League of Nations mandate was formally revoked by the United Nations on 18 July 1947 pursuant to Security Council Resolution 21, making the United States responsible for administration of the islands under the terms of a United Nations trusteeship agreement which established the Trust Territory of the Pacific Islands.[49] Most of the islands subsequently became part of independent states.[25]
