The Islands of the Japanese Mandate in 1937

Japanese Governance of the Mandated Islands
Economic Development
Military Development
The Japanese Mandate and Earhart


The Micronesian Islands – that is, the small islands scattered between the Polynesian triangle to the east and south and the large islands of Melanesia to the west, and occupied by people of the several ethnic stocks and language families collectively referred to as “Micronesian” – were with two exceptions held by the Japanese Empire in 1937. The two exceptions were what is now Kiribati – then known as the Gilbert Islands and administered by the British – and the island of Guam in the Marianas chain, administered by the United States. The islands administered by Japan, under a mandate from the League of Nations, comprised the Marshall Islands in the east, the Caroline Islands in the center-south, and the Mariana Islands in the northwest. These divisions and names are somewhat arbitrary.

The Marshalls were and are a fairly organized archipelago whose people share a common language and culture. The archipelago in turn is made up of two roughly parallel chains of islands – all coral atolls – running northwest-southeast and called the Ratak chain to the east, the Ralik chain to the west. They now constitute the Republic of the Marshall Islands.

The Caroline Islands include both high volcanic islands and atolls, whose people generally recognize themselves as constituting five more or less distinct cultural and political entities. Farthest to the east is the isolated high island of Kosrae, called Kusae in 1937. To the west is the larger high island of Pohnpei, called Ponape in 1937, with several small atoll outliers. Next comes a scattering of atolls centered on Chuuk – Truk in 1937 – a huge atoll with high islands inside its lagoon. The boundary between those atolls whose people relate to Chuuk and those that look toward the next high island, Yap, is rather indistinct culturally and geographically, though it has long been drawn clearly by administering authorities, and is a state boundary today. The people of Yap – actually a complex, compact group of raised limestone, volcanic, and metamorphic islands – are more distinct culturally and linguistically from their neighbors to the east than any of those neighbors are from one another. In the far west, the Palau archipelago, a chain of high, folded, and uplifted islands with several atolls, is culturally and linguistically distinct from Yap as well as from the islands farther east. Today the four island groups from Kosrae through Yap form the Federated States of Micronesia, while Palau is an independent republic. Palau, like the Federated States and the Republic of the Marshall Islands, are linked to the United States by a complex of treaties that collectively describe a condition known as “free association.” They, like the Marianas to the north, were administered by the U.S. after World War II under a United Nations trusteeship agreement as the Trust Territory of the Pacific Islands.

The Marianas form a chain running north toward Japan from Palau and Yap. They are raised limestone, metamorphic, and volcanic islands. The largest and most southerly, Guam, was seized by the U.S. from Spain during the Spanish-American War, and but for its occupation by Japan during World War II, has remained a U.S. territory ever since. The islands north of Guam, the best known being Saipan and Tinian, now comprise the Commonwealth of the Northern Mariana Islands, whose relationship to the U.S. is the same as Puerto Rico’s. The indigenous people of the Marianas, the Chamorro, have a somewhat ambiguous cultural and linguistic relationship to the people of the Carolines, obscured by centuries of Spanish administration and by considerable in-migration from the Carolines during the 19th century.

Occupied for several thousand years by a mosaic of complex cultures, most highly oriented toward the sea, the Marianas, Carolines, and Marshalls became known to the outside world at various times during the 16th through 18th centuries. By the late 19th century the Marianas and Carolines had become bones of contention between Germany and Spain, both of whom had significant economic interests in the area. Pope Leo XII was asked to arbitrate, and awarded the islands to Spain while reserving German rights to free trade.1 Germany annexed the Marshalls in 1885.2

Spain did not invest very heavily in its colonial holdings other than Guam, Saipan, and Pohnpei, and with a few exceptions its influence was not very strongly felt.

In 1898 the United States seized Guam and the Philippines as prizes of the Spanish-American War, but for a time it appeared that the U.S. would have to fight Germany to do so. In the end Germany backed away from a confrontation with America, but purchased Spain’s residual colonial holdings in Micronesia in 1899.3

Germany was a good deal more vigorous in its administration of Micronesia, though its attention like that of the Spanish was most concentrated on the Marianas. After Guam, the Spanish had established Saipan as the overall administrative center of its Micronesian colony, and the Germans maintained this status, putting considerable energy into economic and political development there.

Japanese merchants had already established a presence in Micronesia by the early 20th century, particularly in Chuuk, and many in Japan saw Micronesia as a natural part of the Japanese Empire. So it was no surprise when Japan, a late and not entirely welcome entry into World War I on the side of the Allies, sent an expeditionary force in 1914 to take possession of the islands. The badly outgunned German garrisons surrendered peacefully.4

Britain and the United States had serious reservations about Japanese intentions in Micronesia and in the Pacific generally, but after a good deal of diplomatic maneuvering the League of Nations gave Japan a mandate to administer the islands, subject to League oversight and specified rules.5 In 1937 the Japanese had exercised this mandate for eighteen years, and had had effective control of the islands for twenty.

Japanese Governance of the Mandated Islands

There were several classes of League mandates, each carrying specific rules about trade, military uses, and reporting. Japan was given a “Class C” mandate, authorizing it to administer the mandated islands under its own laws as though they were parts of Japan, but requiring it not to fortify them.6 By the time the mandate was confirmed, Japan had already set up a substantial governmental structure in the islands, and begun investing in their economic development. The seat of government was established at Koror in Palau,7 with district headquarters at Yap, Saipan, Chuuk, Pohnpei, Kosrae, and Jaluit in the Marshalls.8 Competent administrators were assigned, and a vigorous program was begun to train Micronesians to staff the lower rungs of the bureaucracy. As Mark Peattie, an expert on the period, puts it:

Where the Spanish had neglected, and occasionally tyrannized, the islands, and the Germans had seen them as little more than remote trading stations where Pacific breezes might lift the Kaiser’s flag, the new rulers, after some initial miscues, set about administering their mandate with an intensity of attention, purpose, and industry unrivaled elsewhere in the Pacific.9
The Navy administered the islands from 1914 until shortly after the mandate was sealed, withdrawing in 1920 in favor of a civilian colonial government, the Nan’yo-cho.10 Earhart conspiracy theorists sometimes portray the Nan’yo-cho as a mere front for the military, but Peattie’s detailed history suggests a complex, highly nuanced, and not always cordial relationship between the two elements of the Japanese government. The Nan’yo-cho was a multi-layered bureaucracy in which substantial on-the-ground authority was vested in a Japanese-led indigenous police force with broad powers and responsibilities; Peattie compares the Japanese policeman in Micronesia with the district officer in the British island colonies.11 In the district centers and at Koror, however, other administrative levels and specialties were represented, whose representatives
... earnestly and diligently collected statistics, drew up laws and regulations, and drafted reports to the ministries in far-off Tokyo. Pith-helmeted, they presided over a host of public works and programs involving health and sanitation, fisheries, agriculture, harbor improvement, road construction, and land surveys; regularly making the rounds by schooner and launch, they maintained their emperor's writ on the remoter atolls of his tropical domain.12
Despite some protestations to the contrary, the Japanese bureaucracy consistently treated indigenous Micronesians as inferior beings who were expected to serve the Japanese. The Nan’yo-cho promulgated and enforced rules and regulations that undercut and eroded the authorities of the traditional island leadership,13 and established an educational system for Micronesian youth that emphasized diligence, honesty, obedience, and mindfulness of obligations – all excellent qualities to be sure, but all promoted at the expense of qualities like independence of thought and leadership ability.14

Still, many older Micronesians today – and younger Micronesian political theorists – look back on the “Japanese time” as a good time in their islands’ history, largely because of its orderliness and the economic advancement it brought.

Economic Development

Japanese economic involvement in Micronesia had begun in the late 19th century, and by 1908 had led to the creation of the Nan’yo Boeki Kaisha (South Seas Trading Company), generally known as Nambo or NBK. The great cash crop of the islands was copra, of course – the dried meat of coconuts, used in a host of commercial products at the time. The NBK exercised a virtual monopoly over copra production and trade in the mandated islands, and for that matter over trade in general, though shipping between Micronesia and Japan was in the hands of the Nippon Yusen Kaisha (Japan Mail Steamship Company).15 Efforts to develop another important crop, sugar, floundered until the arrival of Matsue Haruji on Saipan in 1920. A man of remarkable energy and determination, Matsue came to be known as the “Sugar King.” Importing workers from Okinawa, he formed the Nan’yo Kohatsu, KK (South Seas Development Company), commonly known as “Nanko” or “NKK.” The NKK was to become the biggest single commercial enterprise in Micronesia,16 and its agribusiness transformed the social and physical face of Saipan.17 In the spirit of what would decades later be known as “Japan, Inc.,” the Nan’yo-cho worked hand in hand with the NKK to advance the latter’s prosperity for the greater good of the Empire. The government also played an active role in operating phosphate mines on Angaur in Palau, and supported a range of other economic development activities. By 1936 it had given birth to the Nan’yo Takushoku, KK (South Seas Colonization Corporation), or “Nantaku,” whose purpose it was to accelerate Japanese colonization and settlement of the islands, intensify exploitation of their resources, and promote industry.18

Among the most profitable of Japanese industries in Micronesia was fishing. Both NBK and NKK put large fleets of fishing boats to sea, and ran substantial fish processing plants on many islands.19 As the industry grew, the need developed for improved ports; though there were and are many excellent harbors throughout Micronesia, their use by more and more, larger and larger fishing boats and other craft required their ongoing improvement. By the late 1920s the Nan'yo-cho was dredging channels and making other improvements to the harbors at Tanapag in Saipan and Malakal in Palau.20 As the 1920s closed, regular scheduled service was being provided to Micronesia from Japan by 4500-ton cargo liners, and immigration to the islands was accelerating.21 Increased colonization and shipping created the need for more port and infrastructure improvements.

They also inevitably created interest in air travel between the mandated islands and Japan, particularly in view of the development of trans-Pacific air service by the British and Americans (exemplified by the British-American conflicts over the Phoenix Islands). The Navy took the lead in developing aviation in Micronesia, flying two flying boats to Saipan in 1929. By 1933 Dai Nippon Koku (Great Japan Airways) had been created, and in that year made a flight to Palau from Yokohama in a Kawanishi flying boat. Although organized as a civilian company, Dai Nippon initially had close links to the military; the Kawanishi was leased from the Navy and flown by a Navy pilot.22 The development of air travel in Micronesia was not hasty; it was 1939 before Dai Nippon established regular scheduled service to Palau, and 1940 before it began to fly east to the Marshalls via Yap, Chuuk, and Pohnpei. The aircraft used on these routes were exclusively flying boats, notably the huge Kawasaki 97.

By 1937, then, economic development in Micronesia was well underway, and with it the development of harbors, railroads, and factories. Immigration from Japan was also proceeding apace, particularly on Saipan where by 1937 almost 90 percent of the population (42,547 out of 46,748) was Japanese.23 Garapan, the major city on Saipan, had become a thoroughly Japanese town,24 as had Koror in Palau. The pace of development increased in Koror, and Palau in general, in 1937 when the pearl and mother-of-pearl industry became lucrative; at this point many people relocated to Palau from the Marianas.25 A significant Japanese population also grew in Pohnpei, in and near the capital town of Kolonia.26 The Japanese were a less dominating presence elsewhere in Micronesia, but their economic and governmental structures were pervasive.

Military Development

While Japan had essentially cornered the market on trade with Micronesia, notwithstanding its mandate obligation to permit free trade, there is no evidence that it had violated the mandate’s strictures against fortifying the islands. The strictures, however, were rather ambiguous; Japan was to refrain from building “fortifications” in the mandate, and from constructing “military or naval bases.”27These terms were left undefined, and obviously many improvements that facilitated economic development could have military uses as well. And as early as 1921, the military began making surveys and plans for rapid deployment into the mandate in the event of hostilities.28

Very soon after seizing the islands in 1914, Japan placed serious restrictions on visits there by ships of other nations. Concern on the part of Britain and the U.S. over this development – both because it restricted trade by their merchants and because it could permit the Japanese to fortify the islands in secret – may have led the U.S. to instigate a diplomatic conflict over a cable relay station on Yap in 1921. In settling its dispute with the U.S. over this station Japan in 1922 agreed to unrestricted access to Micronesian territorial waters by U.S. commercial vessels, and to the extension of an existing free trade agreement, the Treaty of Commerce and Navigation, to the mandated islands.29 Port visits could be carried out only in accordance with complex regulations, however – so complex and restrictive, in fact, that they had the effect of excluding foreign shipping. These regulations were probably intended to support the creation of a Japanese economic monopoly, but their existence and implementation also served to keep other nations in the dark about just what the Empire was up to in its mandated islands.30 The result was suspicion on the part of nations like the U.S., which initiated intelligence operations to find out what was going on.

Dirk Ballendorf, based largely on study of declassified U.S. Office of Naval Intelligence (ONI) documents, sees three sequential phases to pre-War U.S. intelligence gathering in Micronesia. Between 1915 and 1922, most intelligence work involved interviewing people who had traveled to or through the islands for commercial or other reasons. The period from 1922 through 1929 saw the active if not always very effective use of spies operating under cover of commercial and scientific activities. The third, during the 1930s and 1940-41, emphasized monitoring radio transmissions, censoring mails, the continuing use of agents and, in 1941, aerial overflights.31

The observations collected by ONI during the first phase of intelligence gathering document more suspicions than fact. Mr. Wood of the Atkins Kroll commercial company, on a “health trip” through the mandate, visits Jaluit and opines that it is “military.” A German missionary in China reports dry docks and coal piles at Chuuk. German Catholic priests on several islands report radios capable of reaching Japan, “small military forces,” but “no fortifications in place yet.”32 The second phase was apparently not much more informative. One of the best U.S. agents, for example, the naturalist/archaeologist Hans Hornbostel, reported what he thought were unusually large amounts of oil and gasoline coming ashore on Saipan, and thought the island of Rota would make a good airfield.33

By the time U.S. intelligence entered its third phase, there was more to be discovered, and heightened urgency to discovering it. In 1933 Japan announced that it was withdrawing from the League of Nations, while making it clear that it in no way intended to give up the mandated islands. In 1935 its representatives marched out of a conference on naval arms control and it announced its intention to abrogate existing treaties on the subject by the end of 1936. The first day of January 1937 brought the great naval powers into a “treatyless era,” and the Japanese began construction of the giant battleships Yamato and Musashi.34 Japan continued to insist that it was not fortifying the mandated islands, however, and several tours through the islands by objective outside observers, permitted and even sponsored by the Nan’yo-cho, confirmed these assurances.35 Construction of airfields and improved port facilities was underway, but these, it was argued, were being built purely in the interests of economic development. Considering the pace of economic growth and change in Micronesia at the time, this argument made sense and was doubtless in some measure true. Although widely disbelieved at the time, Japan’s assurances have been rather widely accepted by post-War historians.36 Some have been more cautious in their interpretations, however. The historian Mark Peattie notes that between 1934 and 1937 the balance of power in facilities location and design shifted steadily from the Nan’yo-cho to the Navy, and that however justifiable many of the facilities constructed were in the interests of economic development, they could be, and eventually were, used for military purposes.37 And archaeologist D. Colt Denfeld, writing of facilities like Aslito Airfield on Saipan, whose construction began in 1934, says:

Japanese officials interrogated after World War II argued that these were facilities but building plans indicated that they were constructed for military use. Most buildings were of bombproof design and some included functions (such as torpedo assembly) which were relevant exclusively to military activities.38

The Japanese Mandate and Earhart

The most popular of the “conspiracy theories” about the disappearance of Earhart and Noonan has them secretly acting on behalf of the U.S. government to spy on Japanese fortification of the Micronesian islands, leading to their capture and execution. There are several versions of this hypothesis that have them come down on Saipan, in the Marshalls, and in Chuuk. In almost all versions they are eventually imprisoned on Saipan where they either die of natural causes or are executed.

In evaluating these hypotheses from the standpoint of known Japanese activities in Micronesia, there are two major questions. First, would the U.S. have had any reason to organize such a spy mission, and second, would the Japanese, had they discovered it, have had any reason to keep the matter secret and execute the spies?

As we have seen, by 1937 Japan had begun building facilities in Micronesia that certainly had military uses, and almost certainly were explicitly designed with such uses in mind. Certainly the U.S. was suspicious of Japanese intentions in the islands, and its suspicions had to be heightened by Japan’s withdrawal from the League of Nations and its abrogation of the naval treaties. Certainly, too, the U.S. was actively involved in gathering intelligence about what the Japanese were doing in the mandate.

Under these circumstances it is not unreasonable to think that U.S. intelligence would have been interested in having someone fly over key islands in the mandate (though the middle of the night seems a curious time to fly an observation mission), or in justifying an inspection in force in search of an ostensibly lost aircrew (which, however, the U.S. made no vigorous effort to undertake when Earhart and Noonan were lost). Peattie points out that an overflight would have provided little if any useful data,39 but the U.S. had no way of knowing this.

But had Earhart and Noonan actually been commissioned to fly over any of the mandated islands, and wound up landing or crashing there, would the Japanese have had any reason to react by capturing and executing the spies? Here Peattie's observation is relevant:

Had Amelia Earhart flown over any of the Marianas or Carolines ... she would have seen only the same sort of facilities available to Pan-American Airways at its new commercial base at Guam; had she flown over the Marshalls ... she might have seen Japanese warships at Jaluit Atoll (not forbidden by any of the agreements of the 1920s), but no sign of improvements for even commercial aviation.40
But of course, what Earhart and Noonan actually saw or could have seen may not be the relevant variable. No one who has worked in a bureaucracy or read Kafka can have much trouble imagining a situation in which someone makes a stupid mistake – a local military official or police official overreacts to the crash landing of what he thinks is a spy plane – and things spiral out of control, to the point at which there is nothing to do but execute the supposed spies and hide the evidence that it ever happened. It could happen; whether it did happen is another matter entirely.


In summary, then, at the time of the World Flight the Japanese were engaged in fairly aggressive economic development throughout Micronesia, and were beginning serious and surreptitious work on facilities that could be used for military purposes. These projects looked sufficiently innocent, however, that there was little for airborne spies to spy on, and little reason for Japan to react to the discovery of downed flyers by treating them as spies and secretly executing them. This does not mean that the U.S. was not interested in intelligence about Micronesia, however, nor does it mean that the Japanese might not have gotten themselves into a situation from which execution of downed flyers was the only discernible option. There is nothing about the economic, political, or military situation in the mandated islands in 1937 that could preclude this sort of thing from happening, but equally, there was nothing that would make it inevitable or even particularly likely.


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