Truk, A Brief History2

Preparations for War

Japan's secretiveness about the islands, even after the approval of its League of Nations Mandate, did little to abate the suspicions of the Western powers that Japan had sinister plans for the use of the islands. From the very first, Japan did everything possible to discourage foreign visitors to the islands. Within a few years of its taking the islands in 1914. Japanese naval authorities expelled all the foreign missionaries who had been residing there, in some cases for many years. When Catholic missionaries were readmitted in 1921, it was on the condition they be nationals of a neutral nation (Spain). The United States mounted furtive intelligence operations in Micronesia through the 1920's, making use of archaeologists, natural scientists, and such luminaries as the renowned Marine Colonel Earl H. Ellis. Such cloak and dagger operations produced little information of importance and nothing to suggest that Japan was violating the terms of its mandate in the area. Japan's more aggressive stance in Asia during the 1930's, particularly in Manchuria and China, only made the Western powers all the more suspicious. Japan's withdrawal from the League of Nations in 1935, as criticism of its expansionism in Asia mounted, reinforced speculation that the Japanese were secretly fortifying the island.

In fact, Japan had little to hide up to the time of its withdrawal from the League of Nations and continued to submit its annual reports on the Mandate until the beginning of the war. From 1935 Japan began a limited program of airfield construction in the mandate that included the field on Eten, a small island to the south of Dublon. Communications centers and fuel storage facilities were also constructed at this time. Although such improvements could not flatly be called military fortifications, they could clearly serve as such in the event of hostilities. By 1937 the navy, not the civilian administration, took over the responsibility for the construction of these and other projects in the islands. Japan took pains to conceal this from the outside world as the nation drifted ever closer to war with the US. Even so, Japan was careful not to undertake construction projects that were unambiguously of a military nature.

It was in 1939 that military fortification began in earnest. The famous Fourth Fleet was organized and became the first Japanese naval unit assigned to the island Pacific since World War I. With the passage of legislation to mobilize manpower throughout the empire, Korean laborers began to arrive in Truk and other islands to help in the construction of airfields and other facilities. In that year, too, the government began to conscript Micronesians for heavy construction. Even Japanese prisoners were organized into construction battalions and brought to Truk, among other places, where they helped build a new runway on Moen Island.

In February 1942, the commander of the Fourth Fleet arrived in Truk to establish fleet headquarters there. Barracks were built to quarter the naval forces that were arriving in ever greater number, and the athletic field on Dublon was expropriated as a navy drill ground. On all the high islands of Truk, tunnels were blasted with dynamite and gun emplacements were readied. The pace of work hastened as war with the United States became more imminent. The labor force of a year or two earlier was enlarged to 10,000 by the end of 1941. In addition, a defense force of some 850 men were brought in to man the guns that were installed in the final months before the outbreak of the Pacific war.

The Truk Naval Fortress

Known as the "Gibralter of the Pacific", Truk was regarded as the strongest naval base in the Pacific outside of Pearl Harbor. It was an object of dread to Americans in those first months afer the United States entered the war. "To U.S. sailors the word Truk brought visions of a formidable bastion bristling with turreted long-range guns. To airmen the word stirred visions of AA batteries too numerous to count and Zeros by the score swarming from airfields hewn from solid rock. To those who read the Sunday supplements to prewar American newspapers, Truk was a mysterious place in the Central Pacific that Japan had carefully sealed off to preserve its secrets." The reality, however, was quite different.

Japanese policy from the beginning had been to put its limited budget into a large and mobile fleet rather than defensive installations. At the outbreak of the war, Truk had only four anti-aircraft guns, six five-inch coastal guns that were aptly described as "relics of the nineteenth century and the Sino-Japanese War", and eleven 80-millimeter guns to guard the entrance to the lagoon. Only in 1943, when the Allies began their counter-offensive across the Pacific did the Japanese command reinforce the Truk defenses, but even then the island group remained under-equipped. Japan relied largely on the excellent natural assets that Truk offered. The anchorage, one of the best in the world, was protected by a 140-mile long barrier reef that offered four narrow passes through which ships could pass. The ship berths were located near Dublon and the other nearby high islands, far enough from the reef that naval gunfire from outside the lagoon could not reach them. Any attacking force would have to enter the lagoon through one of the passes or rely entirely on its air power to penetrate the natural defenses.

Within a few months of Pearl Harbor, Kwajalein became the advance base for the Japanese thrust eastward, while Rabaul on the northern tip of New Britain became the forward base for the offensive to the south. Equidistant from Rabaul and Kwajalein, Truk became a key staging area for communications between Japan and its two advance bases in the South Pacific. Planes and ships were shuttled to Truk for refueling, repair and deployment to one of the forward bases. With the heightened strategic importance of Truk, theJapanese Combined Fleet soon made this base their rear area headquarters. In July 1942, the fleet steamed into Truk with Admiral Isoroku Yamamoto commanding from the bridge of his flagship Yamato, one of the largest battleships of the day. The Combined Fleet was so called because it was composed of elements of the First, Second and Third Fleets in addition to the Sixth Submarine Fleet all to be deployed in the Pacific as needed and to be called on in the single decisive battle. As the Japanese envisioned it, which would determine the outcome of the war.

Even as the mighty Japanese armada rode anchor at Truk, the support structure there remained grossly inadequate. Repair facilities were too few to handle wartime repairs; only six or seven smaller naval vessels could be repaired at a time. There was but one 2500-ton floating drydock. There were no piers that could provide for large ships, so these had to off-loaded on crude sampans and small craft. To serve this purpose, there was a small support fleet of dozens of small vessels:50 sampans, 15 tugs, three water lighters, three fuel barges and nearly 20 other small craft, Even cranes and warehouses were in short supply. Truk may have been a first-class anchorage, but it was a very poor repair and support base.

Truk did, however, have a number of good airfields. Besides the seaplane base on Dublon that had been constructed before the war, Truk had four other fields ranging in length from 1000 to 1400 meters. The best and most accessible was the field on Eten, which was well-surfaced and equipped with a taxi loop and a modern administration building. There were also two airfields on Moen Island, one of them a seaplane base at the southern tip of the island, and another on Parem. These fields and the 200 or so planes assigned to Truk were to become the key to Truk's defense, such as it was.

As the allies regained the offensive in the Pacific in the Solomons and New Guinea, the Japanese high command was forced to reconsider its strategy. In the fall of 1943, Tokyo decided that it would abandon its offensives and consolidate its defense perimeter. The army was to be sent to reinforce the garrisons in Japan's island possessions against the Allied assault that now seemed inevitable. In January 1944 the first large detachment of army troops was moved into Truk. The second arrived a month later, shortly after the carrier-based air attacks against Truk. Although sources give varying numbers, it appears that, in addition to the 3,000 to 4,000 sailors, there were 10,000 army troops in Truk by march 1944. Army detachments were placed on all the major islands in the eastern part of the lagoon Dublon, Moen, Fefan and Uman and a very small unit was stationed on Tol.

With the army units serving as the core of the labor brigades, the Japanese intensified their efforts to strengthen the defenses of this naval base. The maze of tunnels that ran through the heights of the main islands was extended, and heavy guns were hauled to the peaks of hills to fire on enemy naval vessels. Beach defenses were also prepared against a possible enemy landing. The gun batteries on reef islands were relocated to better sites, additional 120-millimeter and 155-millimeter guns were brought in for the beach areas, and a general plan for the defense of the area was drawn up. Anti-aircraft batteries, which numbered only four at the beginning of the war, were now increased to 40. Yet, even with such improvements, the defenses in Truk remained far too thin to be effective against an all-out assault. Japan was by this time feeling shortages in war materials of all kinds, and even those items that could be spared by Tokyo were often lost to US submarines that cordoned off the islands ever more tightly.

Continued - Brief3