In the early summer of 1944, with blaring headlines making all the world aware of the Normandy invasion and its follow-up operations, public attention in the United States was focused on Europe. Campaigns in the Pacific were dwarfed by the tremendous scale of the Allied drive against Germany. The full significance of the capture of the Southern Marianas, with the American return to Guam, was overshadowed by the more voluminous accounts of the European conflict. Yet, in two short months on these islands, the Japanese lost their last chance for victory in the Pacific.
The Big Picture
By June of 1944 the outer island screen of Japanese defenses had been riddled by American attacks. New bases in the Marshalls had been seized in February at Kwajalein, Majuro, and Eniwetok by forces of the Pacific Ocean Areas. In March and April, landings in the South and Southwest Pacific theaters had added the Admiralties, Emirau, Hollandia, and Aitape to the rapidly growing chain of Allied installations. Shore-based Army, Navy, and Marine air squadrons harassed and pounded by-passed strong points into neutralization. With practiced ease planes of Fast Carrier Task Force 58 struck repeatedly at Truk, the Western Carolines, and Southern Marianas. The outlook for the Japanese was dark, indeed. A strangling noose was tightening around the inner perimeter guarding the path to their homeland.
Threatened at all points on an arc from the Southern Philippines to the Southern Marianas, the Japanese leaders were well aware that the decisive actions of the war were at hand. The fall of the outer zone of defense was not only a tactical loss; it meant the collapse of the entire strategic concept of Imperial Headquarters.1 Recognizing this, Admiral Soemu Toyoda, Commander-in-Chief, Combined Fleet, in a message to all of his commanding officers on 4 May 1944 warned:
The war is drawing close to the lines vital to our national defense. The issue of our national existence is unprecedentedly serious; an unprecedented opportunity exists for deciding who shall be victorious and who defeated.2
In preparation for the expected amphibious strike at the inner ring, the Japanese concentrated most of their remaining carrier strength at Tawi-Tawi, north of Borneo. The enemy's
strategy was simple; at the first definite indication of an American assault, naval forces would assemble, attack, and annihilate the invasion fleet. The Japanese hoped that the first blow would be struck at Palau within easy range of shore-based air, and close to their naval bases. The Americans, however, did not intend to accommodate; they planned to hit a target closer to the homeland.
To most American planners the islands of the Southern Marianas were essential in the drive to shorten the war. They occupy a central position dominating the Western Pacific on an arc from Tokyo through the Ryukus to Formosa, the Philippines, and northern New Guinea.
Their capture would cut the strategic line of communication from Japan to its island holdings in the South Pacific and effectively isolate the garrisons there and would, for the first time during the war, permit Americans to operate on interior rather than exterior lines.3 In addition, enemy planes could no longer stage through the airfields of Saipan, Tinian, and Guam to attack American forces hammering at the Japanese bases in the South and Central Pacific. But uppermost in the minds of the high-level strategists were three further considerations that made the target even more attractive. First, from the same airfields now being used by enemy planes and other sites selected for early development, B-29's of the Army Air Forces could initiate raids on Japan itself. Secondly, capture of Guam would permit the establishment of a submarine refueling point much closer to enemy areas. And finally, Apra Harbor offered a good anchorage for an advance naval base.
By first taking Saipan, headquarters of the defensive cordon in the Central Pacific, Americans could deal a fatal blow to Japanese hopes of retaining their dwindling island possessions. Furthermore, denial of the airstrips on this island to enemy planes would enable the Fifth Fleet to raise an effective air barrier over the Marianas and permit landings to be made on Guam and Tinian.
Guam's capture would return an important possession to American hands and provide a forward supply base for future operations in the Pacific. The flat terrain of Tinian would afford ideal heavy bomber strips from which round-the-clock strikes could be launched against Japan. If the Japanese accepted the challenge of an attack on these islands, a hoped-for showdown battle between the two fleets might take place.
The assault on Saipan,4 15 June 1944,5 brought an immediate Japanese naval reaction.
The enemy's carrier task force came out of hiding and steamed toward the Marianas to meet the American amphibious effort. On 19-20 June 1944, planes from Task Force 58 engaged the enemy fleet, and the action that followed, the Battle of the Philippine Sea, proved disastrous for the Nipponese naval air arm. United States planes destroyed 402 planes, sank one carrier (Hiyo) and two attack oilers, and damaged four carriers, a battleship, and an oiler. In addition, on 19 June, torpedoes from American submarine pickets sank two carriers, the Taiho and Shokaku.6 The badly mauled Japanese retired, but because of the shortage of fuel in destroyers and the disorganization caused by the necessity of taking planes on board during darkness, the U. S. Fifth Fleet could not press the attack further. Nevertheless, a crippling blow had been dealt to enemy naval air power and the danger of interference to the Marianas landings lessened. When Saipan fell on 9 July 1944, the Americans broke into the inner ring of the Japanese defenses and greatly reduced the enemy's potential for holding Guam.
Island of Guam
Guam and the Guamanians
Dominated for years by the Japanese, the Marianas group forms an arc over 400 miles long across the Central Pacific extending from 13° to 20° north latitude and with the center of the group at 144° east longitude. Of its 15 islands, only Saipan, Tinian, Rota, and Guam are inhabitated. The latter, with its 228 square miles, is the largest land mass in the group and approximates the total area of the remaining 14 islands. Long considered of great strategic importance, Guam was the only American territory in the Japanese Pacific stronghold.
The island's irregular shape defies glib description, but its narrow waist divides it roughly into two equal parts. (See Map 2, Map Section) The southern half, an oval about 8 by 16 miles, has its main axis north to south. Jutting to the northeast, the remainder is a rugged area approximately 7 by 14 miles. Fringing the entire island, except at the mouths of streams, is a coral reef shelf ranging from 20 to 700 yards wide.
Towering above the narrow coral sand beaches of the northern half are sheer cliffs 200 to 600 feet high that rim the shoreline from Fadian Point to Tumon Bay. Inland, a vast cascajo (coral limestone) plateau extends from the middle of the island to the northern tip and is broken by three mountain heights: in the south Mt. Barrigada (640 feet), in the east, Mt. Santa Rosa (840 feet), and in the extreme north, Mt. Machanao (576 feet). Growing through the thin layer of red topsoil that covers the cascajo is a tangled mass of tropical forest. Lianas, weeds, air plants, and dense undergrowth choke the space between the trees to form a virtually impassable barrier to cross-country movement. Marking the southern limit of the plateau is a 200-foot bluff that stretches across the island from the northwest slopes of Mt. Barrigada to the upper reaches of Agana7 Bay.
The central lowland belt, dividing the island, extends from Agana Bay on the west coast to Pago Bay on the east coast. It is generally 100-200 feet above sea level and has many small, abrupt changes in elevation near the Pago River. The area contains several springs, the largest of which is located a few feet above sea level on the southern edge of Agana swamp. In this extensive swamp lies the source of a small river which empties into the bay.
Immediately to the south the land begins to rise abruptly and culminates in a wide, long mountain range that parallels the west coast. Once a plateau, this range has been eroded into numerous ravines, valleys, and gorges. Of volcanic origin, it extends from the vicinity of Adelup Point near the waist of the island to Port Ajayan on the southern tip. Just inland from Apra Harbor, rising to a height of 1,082 feet, is the Chachao-Alutom-Tenjo massif, largely composed of sedimentary rock from which the superimposed lava has rotted and fallen away.
South of this mass the range descends to a 400-foot saddle opposite Agat Bay. Then it rises to the Alifan-Lamlam-Bolanos-Sasalaguan ridge line which contains the highest point
on the island, Mt. Lamlam (1,334 feet). The western slopes are steep and merge into low foothills and a narrow belt of rolling lowlands. On the other hand, the eastern slopes are more gradual, becoming, at an elevation of 400 feet a plateau that extends to the coast and ends in high bluffs above a narrow coastal flat. Covering this plateau is a carpet of sword, cogon, and bunch grass interspersed by short stretches of scrub forest.
The moist valleys of the numerous rivers and streams that rise in the central ridge are also heavily forested. Ravines and the lower mountain slopes are covered with the same type of jungle growth found in the northern part of the island. Rivers are all fordable by men afoot, but the steep banks in some cases prevent vehicles from making a crossing. As in the north, there is a large marsh area found in southern Guam; its treacherous depths border coral-jammed Apra Harbor and close most of the neck of Orote Peninsula. The peninsula itself is a cascajo formation with sheer cliffs ringing three-quarters of its perimeter. A matted tangle of low scrub growth stretches from Orote Point to the mangrove swamp on the shores of the harbor. Viewed as a whole, the terrain of Guam presents a formidable barrier to conquest, even without determined human defenders.
The island has another ally over which man has little control: the weather. From July to November, 20 to 25 days of every month are rainy, with more than two-thirds of the years' annual total of 90 inches of rain falling. Roads become quagmires and military operations are considerably hindered. Also from July to November a continuous succession of typhoons to the south and westward produce swells and rough landing conditions on the western beaches. The southern beaches are always bathed in surf from the prevailing trades. However, for the most part the climate is healthful and pleasant, with a constant, uniformly high temperature that varies little from the mean of 87 degrees. The Marianas area has often been called the "white man's tropics," and perhaps it was this beneficent climate that helped influence the original European colonization.8
The first white men to visit the Marianas were sailors of Magellan's globe-circling expedition who reached Guam in March of 1521. The natives actively resented the intrusion and made their displeasure so evident that the Spanish commander named their islands Islas de los Ladrones (Islands of the Thieves).
These original inhabitants, the Chamorros,9 were an imposing people with "a lighter skin, a fine physique, a keen intelligence, and an aggressive spirit,"10 who orignally came from the mainland of Asia. They were sufficiently independent and warlike to resist the Spaniards who returned in 1565 with the intention of colonizing the islands and converting the heathens. Some estimates place the population of the Ladrones at this time very near 75,000. More than a century of continuous resistance to the missionaries and foreign soldiery, crippling inroads by white men's diseases, and steady migration to the Caroline Islands reduced the Chamorros to a mere handful by the time they were ready to submit to church and crown. In 1710, the first recorded census of the natives, who had all been forced to settle on Guam, showed that only 3,539 remained of the once flourishing population.11
Until 1898, the Marianas (the islands had been renamed for the Spanish queen in 1668) remained out of the main stream of world events. In that year, the USS Charleston, accompanying an expeditionary force bound for the Philippines, stopped off at Guam, informed the governor that the United States and Spain
MARINES of the first garrison on Guam shown on the steps of their barracks in an old photograph taken in October 1899. (Photograph courtesy of Walter Patterson.)
were at war, and promptly received the surrender of the defenseless island.12 At the war's end the island became an American possession along with Puerto Rico and the Philippines for which a package price of 20 million dollars was paid. The rest of the Marianas, however, did not pass to control of the United States, and Spain sold them to Germany in 1899. Thus Guam became alien soil in a German sea. When World War I broke out, the Japanese seized the opportunity to expand and they occupied all the German territory north of the equator. The Versailles Treaty confirmed the seizure and the infant League of Nations gave Japan a mandate over these islands, effectively continuing the isolation of Guam.
Following World War I the U. S. Navy Department laid ambitious but abortive plans to make the island into a fortress guarding the routes to the Philippines and the Far East. The tremendous cost of such a project and an almost universal apathy towards military schemes combined to block these hopes. Not until Japan walked out of the League of Nations in 1935 did the average American become aware that something was wrong in the Pacific. The obvious reluctance of Japan to permit League inspection of the islands she held in trust stood as a warning for the future.13 What little money the Navy had available in those depression years was spent to build up Pearl Harbor to insure that there would be at least one strong operating base in the Pacific. Guam remained virtually defenseless, a sitting duck waiting for the time the Japanese chose to strike.
While the military development of Guam had been held in abeyance, the lot of civilians on the island had improved considerably since the end of the Spanish rule. A presidential executive order of 23 December 1898 had placed the island under Navy administration and the
POWERFUL CARABAOS performed a wide variety of tasks for Guamanian farmers and townsmen and symbolize the prewar economy of Guam.
next year the first Marine garrison took up its duties there. A naval officer, usually a captain, was designated governor of Guam and exercised his powers directly under the Secretary of the Navy. For all practical purposes, although his staff of advisors included native leaders, the naval officer was the supreme executive with final legislative power, and the appointment and removal of all officials rested in his hands. Fortunately, this government, especially in its later stages, expressed itself as a form of benevolent paternalism that evidently suited the Guamanians, who by this time were a racial mixture of the original islanders, Spanish, and Filipino colonists. As one naval officer put it, ". . . the Chamorros never failed to show a kindly courtesy towards us. Their generous tolerance and compliance with our orders showed a most complaisant nature."14
By 1941 the native population had more than doubled from the original 9,000 that had been on the island when the Navy took over. About half of the people lived in the capital at Agana and another 3,000 in villages within ten miles' radius. The balance of the population was spread out in coastal villages and farming areas, with the greater percentage in the south. Fewer than 3,000 chose to live on the inhospitable northern plateau.
Although nominally townsmen, many of the Guamanians spent a great deal of their time working coconut plantations, rice fields, and garden plots in the interior. Those who lived on the farms tilled their own small areas and raised a few chickens, pigs, goats, and cattle. With the average ranch being small, cows and horses of the entire community often grazed on communal pastureland near the village. On the larger ranches, in addition to extensive cattle raising, the natives grew the main agricultural products. Vegetables, rice, tropical fruits, copra, and meat were transported to markets by the widely-used two-wheeled carabao carts. Only the most prosperous ranchers could afford motor vehicles to carry their products to town.
Population growth, improved economic and political status, and a vastly increased measure of tolerance on the part of the government were not the only benefits of American rule. The water supply had been augmented in 1940-41 to provide for the Apra Harbor area and garrison and island population in the vicinity of Piti and Sumay. The Navy supervised improvement and maintenance of 85 miles15 of two-way roads. They circled the southern half of the island except for a stretch from Agat to Umatac, where the beach furnished the best route for traveling. In the north, from Ritidian Point to Yigo, the jungle had blocked construction of the proposed Agana-Yigo coast road. Throughout the interior a web of trails and carabao-cart tracks connected the farming hamlets with the main coastal roads. Extensive efforts to make the island economically self-sufficient had been fostered by the naval governors who encouraged the development of local island industries and the export of copra, Guam's biggest money crop. The island's real prosperity, however, derived from the naval facilities maintained there. Piti Navy Yard, the Marine Barracks at Sumay, and the various government departments (schools, hospital,
courts, police) employed a large number of Guamanians. These activities provided a market for most of the native products.
Although in 1941 Guam was only a fueling station for ships making the long runs to the Orient, it did have considerable strategic importance for other reasons. The station of the trans-Pacific cable and the naval radio station at Agana made it a focal point of the communication network in the Pacific. The clippers of Pan American World Airways landing in Apra Harbor on the San Francisco-Manila-Hong Kong run provided an increasingly important link with the United States. Sites for airfields had been surveyed by late 1941, and plans were underway to initiate construction when the war broke out.16
The threatening situation in the Pacific had led the government to order the evacuation of all dependents from Guam, and the last of them left the island on 17 October 1941.17 All classified matter was destroyed on 6 December and the island waited, as did all American Pacific outposts, for word of the outcome of the negotiations in Washington. At 0545, 8 December 1941,18 the Governor, Captain George J. McMillin, USN, received word from the Commander-in-Chief, Asiatic Fleet, of the commencement of hostilities. Reinforcing the message were the first bombs from Saipan-based Japanese planes which fell at 0827.
The initial target was the mine sweeper USS Penguin, whose antiaircraft guns constituted the only weapons available to the garrison larger than .30 caliber machine guns. The attack continued throughout the daylight hours, with small flights of bombers hitting the various naval installations and strafing roads and villages. Agana was evacuated and the small number of enemy nationals rounded up and imprisoned. Among them were the Japanese who "owned the largest and most popular saloons, where the sailors and Marines liked best to hang out and argue the fine points of their professions."19 Any such pleasant memories were soon dispelled when the first casualties of the bombings arrived at the hospital near Agana. Damage to installations was fairly extensive with houses,20 barracks, fuel supplies, and roads being hit repeatedly. Enemy planes sank the Penguin after she put up a creditable fight, and her survivors joined the garrison ashore.
At daylight, 9 December, the bombers came again and repeated the pattern of attacks on naval installations. The Insular Force Guard, about 80 men who had been organized in early 1941 as an infantry unit to augment the native naval militia,21 mustered in Agana and made preparations to protect the government buildings. The rest of the Guam garrison, including the 28 Marines of the Insular Patrol (Police), remained at their posts throughout the island. On Orote Peninsula the complement of the Marine Barracks, Sumay (6 officers, 1 warrant officer, 118 enlisted Marines) under Lieutenant Colonel William K. MacNulty, took up positions in the butts of the rifle range on the Marine Reservation. The inadequate garrison of
Guam made all possible preparations and waited for the Japanese assault.
About 0400, 10 December, flares appeared near Dungcas Beach above Agana and soon rifle fire could be heard in the plaza of the town. A Japanese naval landing party of about 400 men from the 5th Defense Force based on Saipan had run into the Guamanians of the Insular Guard who engaged them in a fire fight. About the same time the enemy's main force, a reinforced brigade of about 5,500 men, landed below Agat.22
Captain McMillin, aware of the overwhelming superiority of the enemy, decided not to endanger the lives of civilians by holding out against such heavy odds. He surrendered the island to the Japanese naval commander shortly after 0600. Scattered fights continued throughout the day as the invaders spread out over the island, but the defenders could offer only token resistance against the conquerors. The bombings and the action after the enemy landing killed 21 civilian and military personnel and wounded many others. But the small loss suffered by the Americans and Japanese on 10 December 1941 gave little indication of the high price to be paid by both sides when United States forces retook the island two and a half years later.23
The enemy evacuated American members of the garrison to prison camps in Japan on 10 January 1942. Soon afterwards Japanese Army troops departed for Rabaul, and the Navy units that had been present at the surrender of the island remained to garrison and govern. At first, the yoke was light, with the Japanese making every effort to gain the good will of the natives. However, those regulations and changes put into effect seemed harsh to people accustomed to the easy-going American administration. Of great injury to the pride of the Guamanians was the changing of the name of their homeland to "Omiyajima" (Great Shrine Island) and that of their capital city to "Akashi" (Red or Bright Stone). In the same vein of keeping the populace always aware of the fact they no longer lived under American supervision, the military ordered schools to teach Japanese instead of English. Even with the institution of food rationing and a system of discipline whereby an entire family or community would receive punishment for the wrong-doings of an individual, the natives retained their attitude of watchful neutrality.
JAPANESE NAVAL TASK FORCE landing site at Dungcas Beach on 10 December 1941 and the route through Agana to Orote Peninsula is shown in this picture from an illustrated review of Japanese naval operations. (Army Photograph.)
They were not happy, but life was endurable.
When the Japanese began to build up Guam's defenses, forced labor supplemented the work of their own construction units. Men, women, and children worked with their hands, and little else, on the airfields being rushed to completion. The Japanese recognized the value of the preliminary work and surveys done by the Americans and proceeded to build airfields on the sites selected on Orote, at Tiyan, and in the vicinity of Dededo.24 But this activity was just the start of the work planned for the unhappy Guamanians, and the worst was yet to come.
When Japanese army units began returning to the island as reinforcements in the spring of 1944, the enemy dropped all pretense of getting along with the natives. The military closed schools, forbade church attendance, and took over all government functions. As the garrison grew larger, an acute shortage of food developed and the Japanese seized all available stockpiles. In addition, they drastically increased forced labor demands and further reduced the already small pittance of food supplies of the natives. A bare subsistence ration was issued to the worker, and those too sick or weak to produce had even this withheld.
Finally, the Japanese ordered all people living in the military areas to evacuate their homes, and herded them into concentration camps in the interior. Medical supplies were limited, sanitation non-existent, and food inadequate. Hundreds died, and small children who did survive became stunted and deformed from disease and malnutrition. Human bodies were beaten and broken, but within them the spirit remained alive. Every bow to a Japanese officer, every blow received for some real or fancied offense, every violation of native customs and traditions only served to heighten the resentment against Japanese rule.25
The Japanese Were Ready26
Heavy air strikes against the Gilbert Islands in September 1943 alerted Japanese Imperial Headquarters to a possible American advance through the Central Pacific. In an attempt to strengthen the island barrier against the advancing enemy, a veteran division, the 13th, was tapped for duty in the Marianas. In October an advance detachment, 300 strong, left Central China with the strongest element slated for the island of Guam. The division itself, which had been fighting in China since 1937, did not follow its advance guard to the Pacific outposts, but remained to take part in the Hengyang-Kweilin (South China) campaign of late 1944. Instead, a substitute division from the formidable Kwantung Army in Manchuria was selected to take its place. This unit, the 29th Division (Lieutenant General Takeshi Takashina), was reorganized early in February 1944 into an RCT-type (Regimental Combat Team) division27 for immediate duty in the Central Pacific.
MAJOR GENERAL TOMITARA HORI, commander of the South Seas Detached Force, the main Japanese Army assault unit during the capture of Guam on 10 December 1941.
Men from the Nagoya District of Honshu Island, most of whom had been in service since 1941, formed the unit's combat teams, the 18th, 38th, and 50th. On 19 February, units of the 29th cleared their training areas near Liaoyang and entrained for Pusan, Korea on the first leg of their journey to Guam.
Even as the 29th left Manchuria, Imperial Headquarters ordered additional troops readied to reinforce the division. Elements of the 1st (Tokyo District) and 11th (Shikoku Island District) Divisions, also of the Kwantung Army, were formed into the 6th Expeditionary Force and sailed from Pusan early in March. They had an uneventful voyage, but such was not the case for their predecessors. Watchdog American submarines caught the 29th's convoy about 48 hours out of Saipan and torpedoed two of the transports, sinking one. This ship, the Sakito Maru, transporting the 18th RCT and eight of the division's tanks, carried to the bottom almost 1,400 men and all of the regiment's equipment. Accompanying destroyers picked up survivors and brought them into Saipan, where the unit was reorganized and partially re-equipped. The ship carrying the 50th RCT received orders to stop at Tinian where the regiment disembarked and took over the island's garrison. The rest of the convoy, carrying division headquarters and the 38th, continued on to Guam, reaching there on 4 March.
On landing, the division joined the 54th Keibitai, a naval guard unit which had garrisoned the island since its seizure by the Japanese on 10 December 1941. Until July 1944 additional naval antiaircraft (AA) and guard units moved to Guam to serve under the 54th's command, so that the total of naval combat troops had reached nearly 3,000 by the time of the American landing. In addition, two naval construction battalions, the 217th and 218th Setsueitai, came in during the occupation to work on Guam's airfields, and their 1,800 men were available as untrained combat troops. Ground remnants of the air groups that had been stationed on the island rounded out the total of available naval forces. Their planes were gone, some lost in attacks on carrier task forces, others shot down over Western New Guinea. To oppose General Douglas MacArthur's landing at Biak on 27 May approximately half of the available naval land-based aircraft had been shuttled down from the Palaus and Marianas.
Consequently, by the time the American assault force appeared off Saipan in June, the Japanese no longer possessed effective shore-based naval air in the Marianas. Tokyo watched intently the progress of the battle for Saipan, and loss of the island led to the decision of enemy Combined Fleet Headquarters that it "had no intention of trying to carry out large-scale attacks, having assumed that Guam and Tinian [also] would be lost."28
With the arrival of the 29th Division headquarters on Guam, command of Guam and Rota passed to an area group headquarters under General Takashina. At this time orders placed all Navy as well as Army forces under his operational control in case the island should be assaulted. On 20 March, the 5,100 men of the 6th Expeditionary Force (six infantry battalions, two artillery battalions, and two engineer companies), commanded by Major General Kiyoshi Shigematsu, arrived and completed the roster of major units charged with the defense of Guam. By 4 June, the depleted 18th Regiment,29 less the 1st Battalion left on Saipan, had rejoined the division, bringing with it two companies of the 9th Tank Regiment. This brought the military strength on the island to approximately 18,500. (See Appendix VII)
Shortly thereafter, Takashina reorganized the 6th Expeditionary Force into two tactical units for greater efficiency. The three infantry battalions of the 11th Division formed four battalions (319th to 322d) of the 48th Independent Mixed Brigade (IMB), while battalions
LIEUTENANT GENERAL TAKESHI TAKASHINA (right), Commanding General, 29th Infantry Division, inspects defenses along Agat Beach with Colonel Tsunetaro Suenaga, Commanding Officer, 38th Infantry. (Army Photograph)
20CM COAST DEFENSE GUN position located on Bangi Point illustrates the half-finished condition of many Japanese defensive installations at the time of the III Amphibious Corps landing. (Navy Photograph.)
from the 1st Division made up the 10th Independent Mixed Regiment (IMR).30 On 23 June 1/10 with an artillery battery and an engineer platoon attached moved to Rota to garrison that island. A few days later, a task force composed of the 3d Battalion, 18th Regiment plus supporting engineers and amphibious transport units followed. According to Lieutenant Colonel Hideyuki Takeda (Operations Officer of the 29th Division) the mission of the force:
. . . was to move to Rota for the purpose of conducting a counter-landing on Saipan, upon suitable opportunity, in order to reinforce the Saipan defense forces. . . . [However,] since the condition of the sea made the plan impossible, it returned to Guam on 29 June. In the course of the amphibious movement a boat accident occurred and two boats and 100 men were lost.31
Surviving troops were immediately assigned defensive positions and started to strengthen their areas as rapidly as possible. Although the remainder of the 29th Division had made intensive efforts to build up beach and airfield defenses, time began to run out. When Japanese commanders found they could not complete all the work that had been planned, they concentrated on strengthening the high ground inland and to the flanks of the most likely landing beaches. From Tumon Bay to Facpi Point obstacles and mines studded the fringing reef, while machine guns, mortars, artillery, and coast defense guns were laid to cover the obstacles and beaches. Small but adequate dumps containing ammunition, rations, and medical supplies were scattered at points throughout the island where area defense forces might make a stand. That the build-up was progressing at a rapid pace is borne out by the fact that late in May American photo reconnaissance planes added 70 new targets to the III Amphibious Corps intelligence maps. On 6 June pilots reported 51 more enemy positions.32
With the capture of 31st Army Headquarters on Saipan, a vast quantity of documents dealing with unit dispositions and strengths throughout the Central Pacific islands fell into American hands. Using this information, intelligence officers drastically revised their estimate of Japanese strength on Guam. An indication of the value of this find is shown in the revisions in order of battle: 8 May, 6,900-9,300 troops; 27 May, 10,100-11,800; 9 July, 27,618-28,118; 18 July, 18,657 (plus aviation ground troops).33 This last figure, accompanied by a detailed breakdown of units present on the island, agreed with very few exceptions with the final order of battle compiled by III Amphibious Corps after contact had been made with the defending forces.34 One item of information not available to corps was the fact that the 31st Army's commander, Lieutenant General Hideyoshi Obata, was on Guam. He had been forced to stop there when the American landing at Saipan caught him returning from an inspection tour of the Palau Islands. From an improvised headquarters, he supervised the defense of the Marianas, leaving the immediate defense of Guam, however, to General Takashina.35
With the help of Saipan information, IIIAC plotted Takashina's main defensive dispositions and distributed a sketch map to units showing the enemy situation at the end of June. Guam had been divided into two major defense sectors: the area from Facpi Point to Agat Bay, including Orote Peninsula, was under the commanding officer of the 38th RCT, Colonel Tsunetaro Suenaga, who had his headquarters in the vicinity of Mt. Alifan; the rest of the island came under the 48th IMB's general, Shigematsu, with local sectors under the commanders of the 10th IMR and the 18th Regiment. (See Map 3) In the Agat sector, 1/38 and 2/38 defended the area from Bangi Point to Agat Village. Naval infantry, antiaircraft, and coast defense36 units mainly from the 54th Keibitai covered Orote Peninsula with its airfield. A battery of mountain artillery37 and the 1st Company, 9th Tank Regiment supported the 38th Infantry.
General Shigematsu's dispositions included the 2d and 3d Battalions of the 10th IMR spread out from Umatac to Yona in southern Guam, with the regimental headquarters at Inarajan. The extreme northern portion of the island was assigned to 2/18 while the headquarters of the regiment was near Mt. Chachao
Japanese Infantry &
21 July 1944
SIX-INCH GUN, part of a three-gun battery on Chonito Cliff, whose fortification was halted by the preliminary bombardment of the Southern Attack Force. Notice the commanding field of fire this gun had over the Asan beachhead. (Navy Photograph.)
and the 3d Battalion in the vicinity of Tepungan. The infantry battalions of the 48th IMB were located as follows: the 320th behind the Asan beaches, the 321st spread out from Agana to the Tiyan airfield, and the 322d at Tumon Bay in the vicinity of the incomplete Dededo airstrip. Two battalions of artillery and the 2d Company, 9th Tank Regiment backed up the beach defenses.
In addition to its headquarters troops, the 29th Division held a substantial mobile reserve in the hills behind Agana. Included in it were the 3d Battalion of the 38th RCT, the 319th Battalion of the 48th IMB, and the 24th Tank Company. Located at the airfields and along the beaches were scattered elements of naval ground and air units manning AA and coast defense gun positions under control of local Army sector commanders.
The preliminary bombardment in June and the long prelanding preparation in July opened the eyes of the Japanese to the beaches selected by the Americans for their landing.38 An artillery officer of the 38th RCT noted the impact area of the "all-day bombings and bombardment" and logically concluded that the landings would take place near Gaan Point.39 Even the privates had the right idea: one from 2/10 noted in his diary on 11 July that "the chances seem to be that the enemy main force plans to
land in the Agana-Piti area."40 Division headquarters acted on the tell-tale information furnished by American bombs and shells and began maneuvering the outlying elements of its command into positions to repulse the expected landings.
Starting on 8 July, the 10th IMR began withdrawing from southern Guam to an assembly area near Yona where it could back up the Asan beaches. The 9th Company of the 10th IMR was assigned on 11 July to reserve positions near Mt. Alifan directly supporting the 38th RCT. Infantry units in the north started moving later in July to the Ordot area to reinforce the 320th Battalion at Asan. Repeated Japanese diary entries for this period indicate that fire from American ships and planes severely handicapped all these movements. One engineer squad leader summed up the general feeling when he wrote, "On this island no matter where one goes the shells follow."41
Even while Japanese units moved into position to cut off the landing areas, the 29th Division maintained effective communication with them by wire42 or radio. The disruptive effect of the continual American pounding slowed, but did not stop the concentration of the enemy. Moving mostly at night, the battalions gradually assembled in their assigned areas. An order signed by General Shigematsu on 15 July indicated he was moving to his battle command post in the Fonte hill mass overlooking the Asan Beach. With final preparations made, the defending Japanese were ordered to "seek certain victory at the beginning of the battle . . . to utterly destroy the landing enemy at the water's edge."43 The Japanese were ready.
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1. Dr. Herbert Rosinski, a noted military analyst, states the basic Japanese plan was one of fighting a "limited war" and called for activities to be restricted to the occupation and defense of Southeast Asia. The attack on Pearl Harbor was only to cripple the American fleet, allowing the Japanese time to prepare outpost defenses. They would then wear out the Americans and finally cause them to "throw [in] the sponge." For a complete discussion of the Japanese strategic concept see Dr. H. Rosinski, "The Strategy of Japan," Brassey's Naval Annual, 1946, (New York, 1946), 99-113.
2. USSBS (Pac), NavAnalysisDiv, The Campaigns of the Pacific War, (Washington, 1946), 223, hereinafter cited as Campaigns.
3. Ltr Adm R. A. Spruance to CMC, 3Dec52.
4. See Maj C. W. Hoffman, Saipan: The Beginning of the End, MC Historical Monograph, (Washington, 1950), hereinafter cited as Saipan.
5. A consistent effort has been made throughout the monograph to standardize dates and times. For the most part these are adjusted local times taken from the action reports of units involved in the operation.
6. Campaigns, 213-215.
7. In the spelling of Agana and other Spanish proper names the anglicized usage of American reports has been used throughout the monograph.
8. The geographical description above was taken from intelligence bulletins prepared for the Guam operation. It furnishes a picture of the island as it was in July 1944 before the bulldozers, graders, and dredges of the Seabees and engineers completely changed the topography. Especially helpful in compiling the description have been: ONI-99, Strategic Study of Guam, 1Feb44, hereinafter cited as ONI-99, and MIS, WD, Survey of Guam, 1943, hereinafter cited as WD Survey.
9. The word "Chamorro" is considered obsolete at the present. "Guamanian" is considered the official designation of the peoples of Guam and is preferred by the natives of the island. Ltr 2dLt V. T. Blaz to author, 26Sept52.
10. R. W. Robson, The Pacific Islands Handbook-1944, (New York, 1945), 136.
11. L. Thompson, Guam and its People, (Princeton, 1947), 34.
12. The instructions to Capt Henry Glass, USN, commanding the Charleston, were to seize Guam, since information indicated that it was the only inhabited island of the group at that time. Consequently, the Spanish retained the rest of the Marianas at the conclusion of the war and were able to place them on the trading block. Lt F. J. Nelson, "Why Guam Alone Is American," USNI Proceedings, August 1936.
13. At the Washington Naval Conference of 1922 both Japan and the U. S. agreed not to fortify their holdings in the Central Pacific.
14. Capt L. W. Johnson, (MC), "Guam--Before December 1941," USNI Proceedings, July 1942, 991, hereinafter cited as Johnson.
15. According to RAdm G. J. McMillin, Governor of Guam at the time of the Japanese attack on 10Dec41, most of the 85 miles of road were built and maintained by Island Government funds, raised by local taxation. U. S. Government funds from the Navy Department were available for the so-called Federal roads, which were principally from Marine Barracks, Sumay to Agana. Ltr RAdm G. J. McMillin to CMC, 3Nov52, hereinafter cited as McMillin.
16. The foregoing historical background is a synthesis of information contained in Thompson, op. cit.; Robson, op. cit.; T. Yanaihara, The Pacific Islands Under Japanese Mandate, (London, 1940); RAdm G. J. Rowcliff, "Guam," USNI Proceedings, July 1945; LCdr F. J. Nelson, "Guam--Our Western Outpost," USNI Proceedings, January 1940.
17. One woman, Mrs. J. A. Hellmers, wife of a Navy CPO, who was too far along in pregnancy to be evacuated stayed on the island. She and her newborn daughter were taken prisoner when the Japanese occupied the island. They were both repatriated, together with the naval nurses taken on Guam, on the exchange ship Asamu Maru in June 1942.
18. Capt G. J. McMillin, Surrender of Guam to the Japanese, official report to CNO, 11Sept45, hereinafter cited as Surrender Report to CNO.
19. Johnson, 998.
20. One of the houses demolished in Agana on 8Dec41 was that of RM 1/C George R. Tweed, USN. Tweed fled to the hills after the Japanese landing and with the help of loyal Guamanians managed to survive the entire period the Americans were gone from Guam. He was the only member of the garrison not killed or captured. Keeping him alive caused many natives to be beaten and robbed of their scarce food supplies, but his continued safety became a symbol of resistance against the Japanese.
21. The members of the Insular Force Guard were in U. S. Government service and received 50 percent of the pay of corresponding ratings in the U. S. Navy. The native militia was a volunteer organization serving without pay or allowances and with no equipment except obsolete and condemned rifles. McMillin.
22. This unit was the South Seas Detached Force under MajGen Tomitara Horii, organized in November 1941 for the purpose of assaulting Pacific bases. It was built around the 114th Inf Regt and reinforced by units of the Japanese 55th Div. MID, WD, Order of Battle for the Japanese Armed Forces, 1Mar45, hereinafter cited as OB for Japanese.
23. The account of the defense and capture of Guam was taken from Surrender Report to CNO. The garrison of the island at the time of its capture was composed of 30 naval officers, six warrant officers, five naval nurses, 230 regular naval enlisted men; seven Marine officers, one warrant officer, 145 Marine enlisted men, and 246 members of the native Insular Force.
24. Only the airfield at Dededo was not operational at the time of the American landing. American surveys had shown that Guam had terrain suitable for a minimum of six long-range bomber strips, 11 medium bomber runways, six fighter, and four emergency airfields. ONI-99.
25. The story of Japanese rule on Guam is taken from Maj F. 0. Hough, The Island War, (Philadelphia, 1947), 282-284, hereinafter cited as The Island War; PFC S. Fink, "Co-Prosperity on Guam," MC Gazette, October 1944, 43-47; interrogations of Guamanians contained in IIIAC C-2 Jnl.
26. In preparing the story of the Japanese buildup on Guam American intelligence journals, reports, and operation plan annexes of IIIAC units have been consulted. In addition, several important Japanese documents have been used extensively to check American findings and insure an accurate narrative. Among them is a study from the files of the OCMH, USA written by officers from Imperial General Headquarters giving the Tokyo view of the Guam campaign, hereinafter cited as Japanese Defense of Guam. The former operations officer of the Japanese 29th Division, LtCol Hideyuki Takeda, who came out of the Guam jungle to surrender following the end of the war, wrote an outline in October 1946 of the Japanese defense plan and operations on the island which is hereinafter cited as Takeda. In February 1952 Col Takeda answered a series of questions from the DirMCHistory that sought to clear up many important disputed points of Japanese strategy and tactics during the defense of the island. This document, probably the most important single enemy source on the Guam operation, will be hereinafter cited as Takeda Letter.
27. The 29th had been a standard triangular division in Manchuria, and upon reorganization dropped its engineer, cavalry, and transport regiments and gained a tank unit. Each of its infantry regiments was assigned an artillery battalion and an engineer company. Transportation was now handled by a motor transport company and a sea transport unit. OB for Japanese, 71-72.
28. USSBS(Pac), NavAnalysisDlv, Interrogations of Japanese Officials, (Washington, 1946), Interrogation No. 448 of Capt Mitsuo Fushida, IJN: Senior Staff Officer, 1st Air Fleet, Sept43-Apr44; Air Staff Officer to CinC, Combined Fleet, Apr44-Sept45. This work will be cited hereinafter by USSBS(Pac) interrogation numbers and descriptions.
29. Infantry battalions of the 18th Regt were understrength because of the sinking of the Sakito Maru, and their organization on Guam included only a headquarters, three rifle companies, and a trench mortar company (seven 90mm's).
30. Infantry battalions of the 48th IMB and 10th IMR were organized into a headquarters, three rifle companies, a machine-gun company, and an infantry gun company (two 47mm AT guns and either two or four howitzers). The 38th RCT's battalions had the same organization, except the gun company had four 37mm AT guns and two howitzers.
31. Takeda Letter.
32. IIIAC OpPlan 1-44, 11May44.
33. Ibid., and TF 56 G-2 Rpt, Appendix H.
34. See Appendix VII, Japanese Order of Battle on Guam. The remarkably accurate order of battle compiled by IIIAC was principally the work of Capt R. H. Beckwith according to the former C-2. Ltr Col W. F. Coleman to author, 23Sept52.
35. Takeda; Japanese Defense of Guam.
36. A tabulation by IIIAC on 10Aug44 showed that 19 8-inch, eight 6-inch, 22 5-inch, and six 3-inch coast defense guns had been destroyed or captured on Guam. IIIAC C-2 Periodic Rpt 21.
37. A document captured on Saipan lists the following Army artillery pieces as being on Guam on 1Jun44:
TF 56 G-2 Rpt, Appendix H.
14 105mm Howitzers 18 75mm Guns 40 75mm Pack Howitzers 8 75mm AA Guns 9 70mm Pack Howitzers 9 57mm AT Guns 30 47mm AT Guns 47 37mm AT Guns 6 20mm AA Guns
38. CruDiv-6 (RAdm C. T. Joy) of the preliminary bombardment group of TF 53 commanded by RAdm W. L. Ainsworth started working over the beaches on Guam as scheduled at 0815, 16 June (W-minus 2). This shelling continued for two hours before Adm Spruance ordered cancellation of 18 June as W-Day because of an imminent fleet engagement. This preliminary bombardment was a clear tip-off to the Japanese as to the exact landing beaches to be used by the Americans. ComFifthFlt WD, June 1944, 12; ltr VAdm W. L. Ainsworth to author, 3Oct52.
39. CinCPac-CinCPOA Item 11,943--Diary of 2dLt Kanemitsu Kurukowa.
40. CinCPac-CinCPOA Item 10,996--Diary of Leading Pvt Murano Kaki.
41. CinCPac-CinCPOA Item 10,410--Diary of unidentified soldier.
42. Wire lines from division to sector defense headquarters were always laid in two and sometimes three separate routes through defiladed areas. Within the sectors, since the Japanese knew the landing areas, they were able to lay their lines in ring shape through protected ravines and gullies on the flanks of the beaches. Takeda Letter.
43. CinCPac-CinCPOA Item 10,377--Agana Sector Garrison Order A-127, 15Jul44.