Nan'yō (Japanese: 南海, South Seas) consisted of several groups of islands (modern-day Palau, Northern Mariana Islands, Caroline Islands and Marshall Islands) in the Pacific Ocean that came under sovereignty of the Empire of Japan after the defeat of the German Empire in Word War I. Japanese ownership was ratified by the Treaty of Versailles.
Japan mounted an aggressive economic development program, promoted immigration and cultural integration of the islands. Japanese, Okinawan and Korean immigrants eventually came to outnumber islanders by as much as two to one. The Imperial Japanese Navy (IJN) began construction of airfields, fortifications, ports, and other military projects in the islands.
After the Great Pacific War it was briefly administered by the Joint Allies Administration for the Pacific (JAAP 1945-1947). The peace terms of the Allies with Japan determined that it would become an independent state, Micronesia, associated with Japan (1946).
The Governor, designated by the Japanese Prime Minister, was usually a navy officer in active duty. the Governor had complete legislative and judicial authority. The Governor reported to Ministry of Colonial Affair. The Imperial Navy was in charge of the administration until 1925 when when the civil managed South Seas Government was established. It assumed administration of police, hospitals, schools, wharfs, research institutes and state companies. A judiciary, with a Court of Appeals and district courts existed. All judges where appointed by the Governor.
Nan'yō was divided in six administrative districts, in charge of a branch administrator.
- Jaluit Atoll
Initially the administration of villages and rural areas was left unchanged in the hands of traditional chiefs. However by the 1930s a series of regulations established a common administration responsible to Japanese authorities.
Cultural integration began strongly in the 1930s with language schools and compulsory schooling of all children and use of Japanese has the medium of teaching. In some places the placement of communal radio sets along the establishment of groceries and general stores managed by Japanese. Secondary schools where built and access opened to Japanese and native children. Approved printed Japanese media was allowed to be distributed for the general public, along a subsidy in its shipment.
Nan'yō produced significant quantities of sugarcane, bananas, pineapples, taro, coconuts, and other tropical farming products on par with Taiwan. The islands also provided bases for Japanese fishing fleets.
In terms of mineral products, many islands yielded phosphates for farming, especially from Angaur island, which produced some 60,000 tonnes per year. Bauxite was another segment of the colonial economic structure, although the mineral was only present in the Palau group.
Large quantities of pearls, both natural and cultured, were also extracted from the islands.
Nan’yo Boeki Kaisha (South Seas Trading Company, NBK or Nambo) exploited and exported, the main cash crop of the islands, copra. Nan’yo Kohatsu, KK (South Seas Development Company, NKK or Nako), became the biggest single commercial enterprise in Micronesia in sugarcane production. The Nan’yo Takushoku, KK (South Seas Colonization Corporation, Nantaku) was created to accelerated colonization with Japanese and Korean citizens. All economic activities where in hand of state-run companies or private monopolies. The South Seas Government was the main employer in the mining of phosphate and bauxite.
Sea ferry services where generally done by the IJN. Cargo and passenger sea shipping where hands of the Nippon Yusen Kabushiki Kaisha (NYK Line). Air services where provided by the Japan Air Transport Corporation, later Imperial Japanese Airways (DNKKK). The islands also allowed for regular flight links for long range seaplanes such as the Kawanishi H6K2-L ("Mavis") of DNKKK. Sea and Air transit where heavily regulated by the IJN in order to keep out non Japanese companies.
Mail and telegraphic services where in charge of Imperial Japanese Post. Radio services began in 1934 with the shortwave radio service of NHK, Radio Japan.