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Part One: Introduction

Chapter 1: Background of Strategy

On 15 June 1944 American forces invaded the island of Saipan thus piercing the first hole in the inner line of island fortifications that the Japanese had laboriously constructed in order to defend their homeland, their empire, and their recent conquests in the western Pacific and in Asia. Saipan is 1,270 nautical miles from Tokyo, 1,430 from Manila, 1,640 from Shanghai, and 3,350 from Honolulu. Located in the southern portion of the Marianas chain, it was the most heavily fortified of that group of islands and was considered by the Japanese to be a keystone in the defensive system for the homeland.

After twenty-four days of strenuous battle and much bloodletting on the part of both victor and vanquished, Saipan was conquered. On 1 August the little island of Tinian, just a few miles to the south, fell to U.S. forces, and in the same month Guam, the southernmost of the Marianas chain, was recaptured from the Japanese, who had wrested it from the Americans during the first days of the war.

Speaking of the fall of Saipan, Fleet Admiral Osami Nagano, Supreme Naval Advisor to the Emperor, could only remark, “Hell is on us.”1 Premier Hideki Tojo publicly announced, “Japan has come to face an unprecedentedly great national crisis.” The following month Tojo resigned in disgrace along with his entire war cabinet. His resignation marked a major turning point in the war. Up to that time the military clique, led and symbolized by Tojo, had been in secure control of the machinery of government and had dictated Imperial policy without any effective restraints. Thereafter, an opposition party with strong inclinations toward terminating the war made gradual but steady inroads into the councils of state, until at last it was able to persuade the Emperor to surrender. The loss of Saipan and the overthrow of Tojo gave this peace party its first opportunity.2

The spark that set off this interesting train of events was a directive issued by the U.S. Joint Chiefs of Staff on 12 March 1944.3 This body – consisting of Admiral William D. Leahy, President Franklin D. Roosevelt’s chief of staff; Admiral Ernest J. King, Chief of Naval Operations and Commander in Chief, U.S. Fleet; General George C. Marshall, Chief of Staff, U.S. Army; and General Henry H. Arnold,

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Commanding General, U.S. Army Air Forces – was responsible, under the President and in conjunction with its British counterpart, for the strategic direction of World War II. On 12 March it ordered Admiral Chester W. Nimitz, Commander in Chief, U.S. Pacific Fleet and Pacific Ocean Areas, to occupy the southern Marianas beginning 15 June next. The objective as stated was “to secure control of sea communications through the Central Pacific by isolating and neutralizing the Carolines and by the establishment of sea and air bases for operations against Japanese sea routes and long range air attacks against the Japanese home land.”

The 12 March directive was the product of a slow if not always steady growth, emerging only after a long and sometimes bitter conflict of strategic ideas, military interests, and personalities. A leading issue of this conflict was what can best be called the “Central Pacific concept” of American strategy in a war against Japan.

Prewar Origins of the Central Pacific Concept

Shortly after the termination of World War I, when Japan’s pretensions in the western Pacific and the Far East were becoming steadily more apparent, American strategic planners set to work to examine possible ways and means of defeating the Japanese Empire in the event of war between the two nations. From these deliberations emerged a series of plans, dating from 1924 through 1938, entitled the ORANGE plans.4 The product of joint Army-Navy effort, these were issued by the Joint Army and Navy Board, the predecessor to the Joint Chiefs of Staff.

Although the several plans varied in detail, certain assumptions remained fairly constant. The basic concept of the war against Japan, as expressed by the Joint Board in 1929, was that it would be “primarily naval in character throughout, unless large Army forces are employed in major land operations in the Western Pacific, directed toward the isolation and exhaustion of Japan, through control of her vital sea communications and through aggressive operations against her armed forces and her economic life.”5 To conduct such a war, the U.S. Fleet must first move west from Hawaii and establish an advanced naval base in the Philippines, preferably at Manila Bay if it could be held. Such an advance would be either a direct movement or a step-by-step process involving seizure and occupation of key Japanese Mandated Islands in the Marshalls and Carolines, depending upon the nature and extent of the enemy resistance. From a naval base in the Philippines, it was presumed that Japanese trade routes through the South China Sea could be cut and Japan’s economic life throttled. American forces might also move north to establish still more bases in the Ryukyus and other islands neighboring Japan, from which American naval control could be exercised over Japanese home waters and American aircraft could harass the homeland itself.

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The plans assumed it would be essential to establish subsidiary U.S. bases in the Japanese Mandates, especially in the Marshalls, for the purpose of protecting the line of communications between the Philippines and the continental United States. It was generally agreed that bases in the Marshalls, and probably in the Carolines, would have to be occupied by U.S. forces either in offensive operations in advance of a fleet approach to the Philippines or as a defensive measure to protect the line of communications of American forces operating in the western Pacific. The Marianas figured only incidentally in the scheme, since they lay north of the main route of advance from Hawaii to the Philippines. Thus first emerged the Central Pacific concept of strategy.

The ORANGE plans were based on the assumption that the United States alone would be engaged in a war with Japan. With the outbreak of war in Europe in 1939, and with the gradual strengthening of bonds between the United States and the anti-Axis nations, especially Great Britain, this assumption no longer held. It became necessary to agree to some combined strategic measures in anticipation of the day when the United States might actively enter the war against the Axis.

As a consequence, British and American military staff representatives met in Washington in early 1941 to discuss possible strategy should the United States become a belligerent.6 In their final report, ABC-1,7 the representatives agreed first that “should the United States be compelled to resort to war,” both nations would consider the Atlantic and European area to be “the decisive theater,” since Germany was the predominant member of the Axis Powers. Thus was enunciated the doctrine of “beat Germany first” that prevailed until the surrender of Germany on 8 May 1945. Until the Germans were defeated, Allied strategy in the Far East would be primarily defensive. American and British forces would defend Hong Kong, the Philippines, and the Netherlands Indies and hold Malaya, Singapore, and Java against Japanese attack. Within this defensive pattern, the U.S. Navy was assigned the specific offensive mission of capturing positions in the Marshalls and preparing to establish control over the entire Caroline and Marshall Islands area.8 Thus was restated the main principle of the ORANGE plans: hold the Philippines, if possible, and gain control over the islands and waters of the Central Pacific west of Hawaii.

In April 1941 the U.S. Joint Board set about bringing its own plans up to date in the light of these American-British Conversations. The new strategic plan, entitled RAINBOW 5, merely restated the decisions of ABC-1 and assigned more specific tasks to the U.S. forces. Germany was to be beaten first; the Philippines were to be held as long as possible; the U.S. Fleet was to prepare to capture positions in the Marshalls and the Carolines.9 Thus, once

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again, the role of the Central Pacific in the forthcoming war against Japan was affirmed.

War in the Pacific: First Year

The rapid succession of Japanese victories after Japan’s attack on Pearl Harbor made it impossible for the United States and her allies to put into immediate execution any of the prewar plans. Guam fell to the invaders, followed by Hong Kong, Singapore, Manila, and the Philippine Islands. In short order the United States and Great Britain were stripped of all the usable advanced bases they once possessed. The Netherlands Indies, Malaya, and Burma were overrun and the Bismarck Archipelago-New Guinea-Solomons area was invaded. By May of 1942 the Japanese were well ensconced in a far-flung system of mutually supporting bases including the Kurils, the Marianas, the Marshalls, the Carolines, the Palaus, and Rabaul (in New Britain), with outposts in the Gilberts, the Solomons, and New Guinea.

Flushed with victory, the Japanese high command decided to ride its good fortune to the limit and push on to Port Moresby, New Guinea – the very threshold of Australia; to New Caledonia, Fiji, and Samoa, astride the sea lanes between Australia and the United States; and to Midway and the western Aleutians. The first plan was frustrated by the Allied naval victory in the Coral Sea in early May 1942, while the second died aborning. The Japanese gained a tenuous foothold in the Aleutians, but in attempting to seize Midway they suffered their first decisive defeat of the war at the hands of the U.S. Pacific Fleet in the great naval and air battle of 3-4 June 1942.10 The time had come for Allied counteraction.

The United States, which had assumed major responsibility for the war in the Pacific, had laid the groundwork for future offensive operations against the enemy. On 30 March 1942 the Joint Chiefs of Staff, with the approval of President Roosevelt, organized the Pacific theater into two commands – the Southwest Pacific Area (SWPA) and the Pacific Ocean Areas (POA). The former fell to the command of General Douglas MacArthur, with headquarters in Australia, and included Australia, New Guinea, the Bismarck Archipelago, the Solomons, the Netherlands Indies (except Sumatra), the Philippines, and adjacent waters.11 The Pacific Ocean Areas was to be commanded by Admiral Nimitz, whose headquarters was at Pearl Harbor and who was concurrently Commander in Chief, U.S. Pacific Fleet. This theater included virtually the entire remainder of the Pacific Ocean. Within its boundaries lay the Hawaiian Islands, Midway, Wake, the Gilberts, the Marshalls, the Carolines, the Palaus, the Marianas, the Bonins, the Ryukyus, Formosa (Taiwan), and the Japanese home islands.12 Because of the immensity of the theater, it was subdivided into three areas, North, Central, and South Pacific. Nimitz directly commanded the first two, but assigned

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Map 1: Pacific Ocean Areas, 
15 June 1944

Map 1: Pacific Ocean Areas, 15 June 1944

the third to a subordinate commander who from October 1942 to June 1944 was Admiral William F. Halsey, Jr.13

The first task facing MacArthur and Nimitz after the Japanese fleet had been turned back at Midway was to render more secure the line of communications between the United States and Australia. On 2 July 1942 the Joint Chiefs of Staff ordered their Pacific commanders to advance through the Solomons and New Guinea and seize the Japanese stronghold of Rabaul. On 1 August 1942 the area under MacArthur’s control was reduced slightly by moving his eastward boundary line from 160°E to 159°E from the equator southward. This in effect took the lower Solomon Islands including Tulagi, Guadalcanal, Florida, the Russells, Malaita, and

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San Cristobal out of MacArthur’s jurisdiction. (Map 1) There followed the lengthy and exhausting Guadalcanal and Papua Campaigns. By January of 1943 the line of communications was safe, even though Rabaul remained in enemy hands.14

The Japanese were at last on the defensive; the losses at Pearl Harbor were more than replaced by the naval repair and construction program. Allied military planners could now direct their attention to devising ways and means of taking up the offensive, and it is not surprising that their thoughts turned once again to the prewar plans for the Pacific.

Revival of the Central Pacific Concept

The Casablanca Conference

In January 1943 President Roosevelt and the U.S. Joint Chiefs of Staff met with Prime Minister Winston S. Churchill and the British Chiefs of Staff at Casablanca, French Morocco. There, the American and British Chiefs, known collectively as the Combined Chiefs of Staff, mapped out as best they could the main lines of global strategy for the coming year.15 In the midst of prolonged and sometimes acrimonious discussion concerning forthcoming operations in Europe and the Mediterranean, proposed offensives in Burma, and aid to China, Admiral King stepped forth to assume the role that he was to fill for the next two years – that of the leading advocate of a greater effort in the Pacific and more specifically of a Central Pacific thrust against the Japanese.

King addressed himself primarily to the problem of where to go after Rabaul was captured – an operation that was optimistically assumed to be already well advanced with the campaigns in Guadalcanal and Papua drawing to a successful close. He adhered to the concept of the ORANGE plans and urged that the first main Allied objective in the Pacific be the Philippines, since they lay athwart the line of communications between Japan and the oil-rich East Indies and since their occupation by Allied forces would permit that line to be cut. The best route to this objective, he claimed, lay through the Central Pacific. Such a drive would involve “establishing a base in the northwestern Marshalls and then proceeding to Truk and the Marianas.” “The Marianas” he added, “are the key of the situation

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because of their location on the Japanese line of communication.”16

An important addition was thus introduced into the ORANGE concept of the war in the Pacific. The Marianas, which had received little attention from the Joint Board in its prewar plans, now emerged as a major objective in the mind of Admiral King. The other participants at the Casablanca meeting were too concerned about more immediate problems to pay much attention to King’s remarks about the Marianas, but the conferees did endorse planning for a drive through the Central Pacific in 1943.

On 17 January the U.S. Joint Staff Planners, a subcommittee of the Joint Chiefs of Staff, presented a fourfold program for the forthcoming year’s operations in the Pacific: (1) seizure of the Solomons, of eastern New Guinea as far as Lae and Salamaua, and of the New Britain-New Ireland area; (2) seizure of Kiska and Agattu in the Aleutians; (3) after the fall of Rabaul, seizure and occupation of the Gilberts, the Marshalls, and the Carolines through Truk, and extension of the occupation of New Guinea to the border of Netherlands New Guinea; and (4) operations in Burma designed to keep China in the war and increase the employment of China-based aircraft against Japanese shipping.17

Most of this program was acceptable to the Combined Chiefs, although they stipulated that the advance in the Central Pacific should not be allowed to prejudice the recapture of Burma. The final agreement at Casablanca authorized plans to be made for a campaign in the Aleutians, an advance northwest from Samoa along the Solomons-New Britain-New Ireland-New Guinea axis to protect the line of communications between the United States and Australia, diversionary attacks against the Malay Barrier, and a Central Pacific advance west against the Truk-Guam line.18

TRIDENT Conference

In May of 1943 the President and the Prime Minister with their Combined Chiefs of Staff convened again, this time in Washington at the TRIDENT Conference.19 Most of the discussion again centered around questions concerning the Mediterranean theater and Burma and China, but during the course of the meeting, the Combined Chiefs reaffirmed their determination to get on with the war in the Central Pacific.20

On 14 May the American representatives circulated to the Combined Chiefs a paper drawn up by the various subcommittees of the Joint Chiefs, entitled Strategic Plan for the Defeat of Japan.21 This paper was more of an estimate than a plan,

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but it did articulate more clearly than before the main strategic principles endorsed by the highest U.S. planners for the war in the Pacific in 1943-44. It was assumed that to bring about the unconditional surrender of Japan it would first be necessary for the Allies to secure a foothold in China in order to make best use of the enormous Chinese manpower and to provide air bases from which to bomb the Japanese mainland. China could be entered by three routes: through Burma, through the Strait of Malacca and the South China Sea to Hong Kong from the west, and across the Pacific through the Celebes Sea to Hong Kong from the east. The British, with American and Chinese aid, should be held responsible for operations along the first two routes. The United States would assume major responsibility for the third.

Next came the question of how American forces could best get to the Celebes Sea and Hong Kong from positions held by the United States. The American planners proposed a two-pronged drive by U.S. forces, one westward from Hawaii through the Central Pacific, the other west and north along the Solomons-Bismarck-New Guinea line in General MacArthur’s Southwest Pacific Area. The two thrusts were to merge in the Philippines-South China Sea area and join in the descent upon Hong Kong. In determining priorities as between the two drives, it was declared that the main effort in the westward advance should be made through the Central Pacific and a subsidiary role assigned to the South and Southwest Pacific.

Once again Admiral King took the floor to press the argument in favor of the Central Pacific drive and more particularly to champion his favorite project, the invasion of the Marianas. For years, he said, officers at the Naval War College in Newport had been studying the problem of supporting or recovering the Philippines as the sine qua non of defeating Japan. Their conclusions all pointed to the route straight through the Pacific from the Hawaiian Islands as the best approach. The Marianas, he insisted, were the key to the western Pacific. A major offensive there, he claimed, would seriously jeopardize Japanese lines of communications, most probably force the Japanese Fleet into a decisive naval engagement, and provide bases from which to bomb the Japanese home islands.22

In its final session at TRIDENT the Combined Chiefs of Staff, although not committing themselves on the question of the Marianas, agreed to American recommendations for a two-pronged attack across the Pacific. Specifically, they listed the following strategic objectives in the Pacific for 1943-44:

1. Conducting air operations in and from China,

2. Ejection of the Japanese from the Aleutians,

3. Seizure of the Marshall and the Caroline Islands,

4. Seizure of the Solomons, the Bismarck Archipelago, and Japanese-held New Guinea, and Intensification of operations against enemy lines of communication.

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Two months later the Joint Chiefs of Staff decided to modify the plans for launching the Central Pacific drive. A direct assault on the Marshalls from Hawaii, they reasoned, would require more shipping and troops than were immediately available in the Central Pacific and might necessitate draining General MacArthur’s Southwest Pacific Area of some of its resources. Also, it would be well to have better aerial photographs of the Marshalls before attempting the dangerous amphibious assault on these Japanese strongholds about which almost nothing was known. Air bases from which photographic missions could be flown should therefore be built close to the Marshalls. Largely for these reasons the Joint Chiefs, on 20 July, ordered Nimitz to capture Tarawa, in the Gilberts, and Nauru as a preliminary to going into the Marshalls themselves. The target date selected was 15 November 1943.23

In August the Combined Chiefs, meeting at Quebec for the QUADRANT Conference, accepted the revision as well as a schedule of operations proposed by the American representatives for the period after the capture of the Marshalls. For the Central Pacific this included the capture of Ponape, Woleai, and Truk in the Carolines, the development of Truk as a major fleet base, and the seizure of Yap and the Palaus. At Admiral King’s suggestion, an invasion of the Marianas was included in this program as a possible alternative to the Palaus or as a concurrent operation.24

A few days after this decision was made Admiral Nimitz suggested one further change in the plan for initiating the Central Pacific drive. He proposed substituting Makin in the Gilberts for Nauru because Makin could more easily be assaulted and because it was closer to the Marshalls. The proposal was accepted, and Nimitz was authorized to seize Tarawa, Makin, and Apamama in the Gilberts.25 On 20 November 1943 simultaneous amphibious landings were launched against Makin and Tarawa by elements of the 27th Infantry Division and the 2nd Marine Division, respectively. Within four days both atolls were captured, following which Apamama was occupied.26 The Central Pacific drive was under way.

General MacArthur’s Strategy

Meanwhile, halfway around the world at his headquarters in Brisbane, General MacArthur was developing strategic plans that were not always consonant with the ideas prevailing among high echelon

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planners in Washington. MacArthur, having left the Philippines in early 1942, was determined to return as quickly and with as strong a force as possible. He was also determined that the major role in this undertaking should be assigned to the forces under his command and that the main approach to the Philippines should be made through his own Southwest Pacific theater.

In early 1943 MacArthur’s immediate concern was with current operations leading up to the eventual capture of Rabaul.27 At the same time, his staff was preparing a long-range plan (RENO I) for a return to the Philippines. As first set forth in February 1943, this plan called for the progressive seizure in New Guinea of Hansa Bay, Hollandia, Geelvink Bay, and the Vogelkop Peninsula. With the north coast of New Guinea under control, Southwest Pacific forces would then advance north to Halmahera or to the Celebes before the final jump into the southern Philippines.28

This schedule of operations expressed perfectly MacArthur’s fundamental strategic ideas. The Philippines could best be approached by a series of amphibious jumps along the entire northern coast of New Guinea, each so distanced as to permit full cover by land-based aviation. A similar move into Halmahera or to the Celebes would bring him to the threshold of the Philippines. Then, with his eastern flank secured by previous capture of the Palaus and his western flank possibly protected by the occupation of islands in the Arafura Sea, he would be fully prepared to make good his promise to return.

Preoccupied as he was with his own theater, MacArthur could only view with alarm the growing pressure for an advance through the Central Pacific. The Joint Chiefs of Staff and the Combined Chiefs of Staff notwithstanding, he strongly opposed an invasion of the Marshall Islands. Even after the Combined Chiefs had approved and authorized the Marshalls operation, he radioed General Marshall:

From a broad strategic viewpoint I am convinced that the best course of offensive action in the Pacific is a movement from Australia through New Guinea to Mindanao. This movement can be supported by land based aircraft which is utterly essential and will immediately cut the enemy lines from Japan to his conquered territory to the southward. By contrast a movement through the mandated islands will be a series of amphibious attacks with the support of carrier based aircraft against objectives defended by Naval units and ground troops supported by land based aviation. Midway stands as an example of the hazards of such operations. Moreover no vital strategic objective is reached until the series of amphibious frontal attacks succeed in reaching Mindanao. The factors upon which the old Orange plan were based have been greatly altered by the hostile conquest of Malaya and the Netherlands East Indies and by the availability of Australia as a base. ...29

This protest may have helped persuade the Joint Chiefs to postpone the Marshalls operation until the Gilberts were taken,30 but it did nothing to sway the majority of Washington planners from their determination to attack through the Central Pacific. Two months later, in August at the

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Quebec meeting of the Combined Chiefs of Staff (QUADRANT), it was decided, against General MacArthur’s previous advice, to bypass Rabaul.31 These decisions on the part of higher authority did nothing to dissuade the Southwest Pacific commander from continuing his opposition to an extension of the Central Pacific drive. Specifically, he was strongly set against an invasion of the Marianas.32

Enter the Army Air Forces

In the autumn of 1943 a new factor entered into the strategic picture of the war against Japan – a factor that was to have an important bearing on the decision to invade the Marianas. The Army Air Forces announced the imminent appearance of a very long range bomber – the B-29.

An experimental model of the plane was first flown in September 1942, but it took about another year to iron out the “bugs” and make arrangements for quantity production. From the point of view of strategic bombing, the outstanding characteristic of this four-engine plane was that with a bomb load of four tons it had an estimated range of approximately 3,500 miles. In effect, once the B-29 was produced in sufficient quantity, mass bombing raids could be conducted from friendly air bases against enemy targets located as much as 1,750 miles away, although for optimum efficiency and safety a 1,500-mile radius was usually used as a basis for calculation.33

As 1943 drew to a close, it became apparent that the B-29’s would not be off the production line in sufficient number in time to play a significant role in the preinvasion bombardment of Europe, and that in any case the B-17’s and B-24’s already assigned to the European theater were adequate for the job there.34 The question then arose as to how the B-29’s could best be employed against Japan. To which of the various theaters of operations in the Pacific and Far East should the bulk of the bombers be assigned? Three possibilities suggested themselves: Australia, China, and the Marianas.

From the Southwest Pacific came urgent representations by Lt. Gen. George C. Kenney of the Fifth Air Force that first priority in the allocation of the new bombers be assigned to his command. He argued that the best way of using the B-29’s against Japan was to knock out the petroleum

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industry in the Netherlands Indies from bases in Australia. In Washington, however, the Air Forces chief, General Arnold, and his staff had other ideas, and Kenney’s suggestion was rejected.35

At the Quebec conference of August 1943 General Arnold presented to the Combined Chiefs his “Air Plan for the Defeat of Japan.”36 Arnold estimated that by October 1944 ten B-29 groups of twenty-eight planes each might be available for employment against Japan. It was assumed that by that time no Pacific island within fifteen hundred miles of the Japanese main island of Honshu would have been captured. Therefore he proposed to build a chain of airfields north and south of Changsha in China, all of which would be within the required range of most of Japan’s war industries. Since the Air Forces high command refused to believe either that a port on the east coast of China could be captured in time to supply these operations or that the Burma Road could be opened, it concluded that logistical support of any airfield built in China must come from India, flown over the Hump in B-24’s.37

Air Forces planners were none too happy about basing their new bombers in China, partly because of the logistical difficulties involved and partly because they were skeptical of the ability of the Chinese to hold the fields against the Japanese.38 Hence, after the conclusion of the Quebec conference, they urged that the Marianas be seized and that D Day for the operation be advanced to mid-1944 by neutralizing and bypassing intervening Pacific islands.39 The Air Forces planners argued strongly that “plans for the acceleration of the defeat of Japan would place emphasis upon the seizure of the Marianas at the earliest possible date, with the establishment of heavy bomber bases as the primary mission.”40 The Marianas, it will be recalled, were about 1,270 miles from Tokyo, well within the estimated optimum 1,500-mile cruising radius of the B-29’s.

Cairo Conference

At last Admiral King had a powerful ally in his persistent campaign for an invasion of the Marianas. At the meeting of the President and Prime Minister with the Combined Chiefs in Cairo in December 1943 (SEXTANT), the joint Navy-Air Forces efforts bore fruit. Among the operations submitted to and approved by President Roosevelt and Prime Minister Churchill was the “seizure of Guam and the Japanese Marianas,” tentatively set for 1 October 1944.

This operation was to follow the capture of important objectives in the Marshalls in January, Ponape in the Carolines in May, and Truk in July. Meanwhile, General MacArthur was scheduled to seize Kavieng on New Ireland, Manus Island in the Admiralties, and Hansa Bay on the northeast coast of New Guinea, and then

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move on to the tip of Vogelkop Peninsula by August 1944.41

The Combined Chiefs chose this occasion to again endorse the Central Pacific route as part of a two-pronged drive to Japan. In presenting their “Overall Plan for the Defeat of Japan,” they stated that their ultimate aim was “to obtain objectives from which we can conduct intensive air bombardment and establish a sea and air blockade against Japan, and from which to invade Japan proper if this should prove necessary.” This would necessitate one advance along the New Guinea-Netherlands Indies-Philippines axis and another through the Central Pacific in time for a major assault in the area of Formosa-Luzon-China by the spring of 1945. The two lines of advance were to be “mutually supporting,” but should there be conflicts, “due weight should be accorded to the fact that operations in the Central Pacific promise at this time a more rapid advance toward Japan and her vital lines of communication; the earlier acquisition of strategic air bases closer to the Japanese homeland; and, of greatest importance, are more likely to precipitate a decisive engagement with the Japanese Fleet.”42 Here in a capsule was the rationale of the Central Pacific concept of strategy.

Scheduling Operations

Upon receiving word of these latest decisions of the Combined Chiefs of Staff, Admiral Nimitz set about preparing a schedule for forthcoming operations in the Central Pacific. A preliminary draft of his campaign plan, GRANITE, was finished by 27 December. It tentatively outlined operations as follows:–43

Capture of Date
Kwajalein 31 January 1944
Kavieng (and air attack on Truk) 20 March 1944
Manus 20 April 1944
Eniwetok 1 May 1944
Mortlock (Nomoi Is.) 1 July 1944
Truk 15 August 1944
Saipan, Tinian, and Guam 15 November 1944

On 13 January, Nimitz issued another GRANITE plan revising his original somewhat.44 Operations to seize Mortlock Island and Truk were scheduled for 1 August. The possibility of bypassing Truk was considered, and it was suggested that if Truk could be bypassed, the Palaus should be invaded by Central Pacific forces on 1 August. The Marianas could then be invaded by 1 November since capture of the Palaus, it was assumed, would be a less costly and time-consuming venture than assaulting the Japanese stronghold on Truk. In any case, both the original plan and the revision looked to the Marianas as the culmination of the 1944 campaign.

A curious turn of events in Pacific planning now took place. In order better to coordinate future operations in the two Pacific theaters, a meeting of representatives of the Southwest Pacific and the Pacific Ocean Areas was convened at Pearl

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Harbor in the last days of January 1944. Present, among others, were Admiral Nimitz, and from his staff, Rear Adm. Charles H. McMorris, Rear Adm. Forrest P. Sherman, and Vice Adm. John H. Towers, Commander, Air Force Pacific. From the Southwest Pacific came Maj. Gen. Richard K. Sutherland, MacArthur’s chief of staff; General Kenney, Commander, Allied Air Forces, Southwest Pacific Area; and Vice Adm. Thomas C. Kinkaid, Commander, Allied Naval Forces, Southwest Pacific Area.45

Admiral Nimitz presented his revised GRANITE plan for the consideration of the conferees. Immediately, and from all sides, objections were voiced to the proposal to invade the Marianas. General Sutherland advocated pooling all available resources in the Pacific and concentrating upon operations in MacArthur’s theater. “If Central Pacific will move against Palau as the next operation after the Marshalls,” he argued, “and make available to Southwest Pacific Area the amphibious force now contemplated for Truk, we can take all of New Guinea, the Kai and Tanimbars, and Halmahera in time to join you in amphibious movement to Mindanao this year.” General Kenney spoke of bombing Japan by B-29’s based on the Marianas as “just a stunt.” Admiral Kinkaid remarked that “any talk of the Marianas for a base leaves me entirely cold.”46

Even Nimitz’ own staff members showed themselves to be less than enthusiastic over the Marianas, although Nimitz himself favored the project. Admiral McMorris doubted if long-range bombing from the Marianas would cause the capitulation of Japan. Admiral Sherman admitted that operations in the Marianas would be extremely costly and that when captured the harbors would be of limited usefulness to the Navy.

When word of these proceedings reached Admiral King, he read them “with indignant dismay.” In a stern message to Nimitz he pointed out, “The idea of rolling up the Japanese along the New Guinea coast, through Halmahera and Mindanao, and up through the Philippines to Luzon, as our major strategic concept, to the exclusion of clearing our Central Pacific line of communications to the Philippines, is to me absurd. Further, it is not in accordance with the decisions of the Joint Chiefs of Staff.” Assuming correctly that Nimitz agreed with his own strategic ideas, he continued, “I’m afraid ... that you have not ... maintained these views sufficiently positively vis-à-vis the officers from the South and Southwest Pacific.”47 Admiral King was not one to stand idly by while theater staffs undermined his favorite and long-nourished war plan almost at the very moment of its fruition.

Acceleration of Operations

On 31 January Central Pacific forces attacked Kwajalein Atoll in the central Marshalls and, after a four-day fight by the 7th Infantry Division and the 4th Marine Division, secured the objective. At the same time, Majuro in the eastern Marshalls

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was occupied without a battle.48 The conquest of these important positions had been relatively easy, and the reserve troops intended for the operation had not been committed. Nimitz could thus speed up his plan for moving into the western Marshalls, and accordingly he launched, on order, an amphibious assault against Eniwetok on 17 February, two months ahead of schedule. At the same time he delivered a carrier strike against Truk.49

Eniwetok fell in six days before the combined assault of the 22nd Marines and the 106th Regimental Combat Team of the 27th Infantry Division. On 17-18 February (Tokyo time) Rear Adm. Marc A. Mitscher’s Fast Carrier Force struck the once mighty Japanese bastion at Truk, destroying at least seventy planes on the ground and in the air and about 200,000 tons of merchant shipping in the harbor.50 The defenses of Truk were so weak as to lend strong support to the idea that it might be bypassed altogether.

Shortly after the successful conclusion of these operations in the Central Pacific, General MacArthur found opportunity to step up his own schedule. The most recently approved plans called for the Southwest Pacific Area commander to conduct simultaneous invasions of Kavieng on New Ireland and Manus in the Admiralties on 1 April.51 Then, on 23 February, an incident took place that persuaded MacArthur that he could safely accelerate at least part of this plan. Planes from the Southwest Pacific flying over the Admiralties on that date reported no evidence of the enemy. The general decided to act at once. He dispatched elements of the 1st Cavalry Division to Los Negros to conduct a reconnaissance in force and, when initial resistance was discovered to be light, sent the rest of the division in to capture the entire Admiralties group.52

Washington Planning Conferences, February–March 1944

In the light of these events, the time had obviously come for the Washington planners to reconsider their schedule of operations for both Pacific theaters for the rest of 1944.

Most planners by this time agreed that the primary objective for the next phase of the war against Japan was to establish a lodgment somewhere in the “strategic triangle” represented by Luzon, Formosa, and the neighboring China coast. From there it was believed that communications between the Japanese homeland and the Netherlands Indies could be completely cut off, bases for the very long range bombers could be set up within effective range of the enemy’s industrial centers, and forward bases could be established for the ultimate invasion of Japan, if that operation should prove necessary.

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Beyond this point agreement ceased. The arguments that ensued were many and various, but they can be resolved into two main issues. First, which was the better route of approach to the strategic triangle, the Central Pacific route through the mandated islands or the Southwest Pacific route along the coast of New Guinea to Mindanao? Second, which of the two theaters would be given priority in the allocation of resources, especially those troops, ships, and aircraft that had until now been assigned to the South Pacific, a command that had practically completed its mission and was about to become a rear area?

Early in February Admiral Sherman from Nimitz’ staff and General Sutherland, MacArthur’s chief of staff, appeared in Washington to represent their respective commanders in the discussions that the Joint Chiefs of Staff and their subordinate committees were to hold. Sutherland argued that RENO and GRANITE plans were “relatively weak and slow of progress.” As a substitution, he proposed “an advance along the general axis, New Guinea-Mindanao, with combined forces.” Truk, he believed, could be bypassed and, with “the capture of Truk thus obviated, amphibious forces can be combined for an advance along the northern coast of New Guinea.” This, he claimed, would enable United States forces to enter Mindanao as early as 1 December 1944. For such a drive, naval forces could be based at Manus Island. He did not propose to limit the freedom of action of the Pacific Fleet. Admiral Nimitz and General MacArthur could operate by cooperation. But, he added, the “Southwest Pacific Area needs certain naval forces for direct support of its operations. It is General MacArthur’s hope that Admiral Halsey will be assigned as Commander, Allied Naval Forces, because of his ability, rank, prestige, and experience.”53

From General MacArthur himself came representations of the same nature. To General Marshall he radioed:–

There are now large forces available in the Pacific which with the accretions scheduled for the current year would permit the execution of an offensive which would place us in the Philippines in December if the forces were employed in effective combination. However, under the plan of campaign that has been prepared in Washington, the forces will be employed in two weak thrusts which cannot attain the major strategic objective until several months later. ...54

In the same message MacArthur insisted that the forces of the South Pacific should remain under his command. These forces, he argued, had been engaged in operations within his own theater since their advance from Guadalcanal. He could not continue to operate effectively without them. “I must state,” he added, “that any reduction in the forces presently engaged in the Southwest Pacific by actual withdrawal of forces of any category would be incomprehensible.”55

At the same meeting of the Joint Chiefs of Staff addressed by General Sutherland, Admiral Sherman attempted to explain Nimitz’ Plan GRANITE. The plan, he pointed out, differed from that proposed by General MacArthur in that it “envisages occupation of Luzon at the same time that an attack is made in the south [Mindanao] and is predicated upon the occupation of Eniwetok about 1 May, the

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Carolines about 1 August, and the Marianas, or such other point as might be selected as the next objective, by the end of the year.”56

MacArthur’s chief antagonist in this strategic debate was neither Sherman nor Nimitz, but, as usual, Admiral King. King vigorously opposed handing MacArthur the naval forces of the South Pacific. MacArthur already had the Seventh Fleet under his command, King argued. The South Pacific forces were operating in a separate area and were “primarily concerned in such circumstances with the probability of enemy forces from the Pacific Ocean Areas threatening the operations of both the South and Southwest Pacific.” King could see no sound reason for placing them under MacArthur.57 He called attention to the decision of the Combined Chiefs of Staff at Cairo (SEXTANT) that the advance in the Pacific should be along two axes and that in case of conflicts between the two, “due weight should be accorded to the fact that operations in the Central Pacific promise at this time a more rapid advance toward Japan and her vital line of communications.”58 “General MacArthur,” said King, “has apparently not accepted this decision and desires a commitment to an advance along a single axis. I do not think that this is a propitious time to change our agreed strategy.”59 At this point in the argument, General Marshall suggested that, in the light of developments since the Cairo conference, the time had come for the Joint Chiefs to issue a new directive to both Pacific commanders. Specifically, Marshall recommended that the Joint Strategic Survey Committee, which consisted of Vice Adm. Russell Willson (Navy), Lt. Gen. Stanley D. Embick (Army), and Maj. Gen. Muir S. Fairchild (Army Air Forces), be directed to study the matter anew and report its views as to what geographic objectives should be seized, the order of their seizure, and what axis of advance appeared to offer the best chance for victory in the Pacific.60 Admiral King immediately concurred.61

To the disappointment of the advocates of the Southwest Pacific concept of strategy, the Joint Strategic Survey Committee came forth with a statement clearly favoring King’s and Nimitz’ strategic plan.62 The committee, repeating its earlier convictions, stated that the Joint Chiefs of Staff “should resolve the present situation as between these two plans by deciding and directing that the primary effort against Japan will be made through the Central Pacific, with operations in the Southwest Pacific cooperating with and supporting that effort.” The primary objective, said the committee, was the Formosa-Luzon-China triangle, and that objective “would seem to be more effectively supported by the Central Pacific concept than by the concept of the Southwest Pacific. The former leads most directly and most promptly to the vital Formosa, Luzon, China coast area. The latter after reaching Mindanao will require further extensive

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operations before reaching that vital area.”63

The Joint Strategic Survey Committee report not only disappointed the representatives of the Southwest Pacific but also failed to satisfy General Marshall. He did not feel that the committee had sufficiently explored the problem of allotting resources between the two theaters or the question of how best to employ the great Allied superiority in land-based air.64 He wanted other subcommittees of the Joint Chiefs, specifically the Joint Staff Planners and the Joint Logistics Committee, to study the matter further.65 In reply to these proposals, Admiral King, while agreeing in principle that further long range studies would be beneficial, expressed his fear that any more delays in committee might kill the momentum of the drive now under way in the Pacific.66

With Admiral King pressing for immediate action either in the direction of Truk or straight for the Marianas or the Palaus, General MacArthur on 5 March came forward with a proposal to accelerate operations in his own theater. He advised the Joint Chiefs of Staff to omit the Hansa Bay operation scheduled for about 22 April and to move instead to Hollandia, some three hundred miles up the coast of New Guinea. To accomplish this, he proposed to use not only the forces of the South and Southwest Pacific Areas but also Central Pacific aircraft carriers and other shipping tentatively earmarked to support the Kavieng-Manus operation.67

These suggestions were in keeping with General MacArthur’s latest RENO plan, which reached Washington within a few days. It proposed a four-phase program: first, a continued advance along the north coast of New Guinea through Hollandia to Geelvink Bay; second, establishment of air bases in the Arafura Sea area for strategic bombing in the Netherlands Indies and to support subsequent operations into the Vogelkop and Halmahera; third, seizure of the western tip of the Vogelkop and Halmahera; and fourth, occupation of Mindanao, southernmost of the Philippines, and the establishment of bases there for an attack upon the Formosa-Luzon-China coast area.68

Admiral Nimitz, who had meanwhile been summoned to Washington, was quick to note that these proposals, if accepted, would have the effect of slowing up operations in his own theater. To the Joint Chiefs he argued that a retention by MacArthur of forces from the Central Pacific after the capture of Kavieng and Manus would result in “stopping the Central Pacific Campaign, losing its momentum, deferring movement into the MARIANAS until the approach of the typhoon season, and by allowing the enemy additional time to strengthen his defenses in the CAROLINES and MARIANAS would jeopardize our ability to reach the LUZON–FORMOSA–CHINA area

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in early 1945 as now planned.”69

On the affirmative side, Nimitz suggested two alternative schedules for the remainder of 1944. The first contemplated an invasion of Truk on 15 June, the southern Marianas on 1 September, and the Palaus on 15 November. The second proposed bypassing Truk and going into the southern Marianas on 15 June, Woleai on 15 July, Yap on 1 September, and the Palaus on 1 November. On reconsideration, Nimitz decided that, if the second schedule were accepted, the capture of Yap could be deferred until the Palaus had been taken and that a fleet harbor could be established in Ulithi. This would advance the target date for the Palaus to October.70

In the end, the Joint Chiefs of Staff accepted neither MacArthur’s nor Nimitz’ schedules in toto. Nor did they accept without change the final conclusion of the Joint Strategic Survey Committee that to seize the desired objective in the Formosa-Luzon-China coast area, “a fundamental strategic prerequisite is our control of the Marianas, Carolines, Palau [Pacific] Ocean area.”71 At the insistence of General Marshall, Mindanao was added to the vital intermediate objectives that United States forces must capture before proceeding on to the strategic triangle.72

Thus the directive that the Joint Chiefs of Staff issued to General MacArthur and Admiral Nimitz on 12 March represented in a sense a compromise between the Central Pacific and the Southwest Pacific concepts of strategy. It declared “that the most feasible approach to the Formosa-Luzon-China area is by way of Marianas-Carolines-Palau-Mindanao area, and that the control of the Marianas-Carolines-Palau area is essential to the projection of our forces into the former area, and their subsequent effective employment therefrom.” Specifically, the Joint Chiefs ordered:–

1. Cancellation of the Kavieng operation and the complete isolation of the Rabaul-Kavieng area with the minimum commitment of forces.

2. Early completion of the occupation of Manus and its development as an air and fleet base.

3. Occupation of Hollandia by MacArthur, target date 15 April 1944.

4. Establishment of control of the Marianas–Carolines–Palau area by Nimitz’ forces by neutralizing Truk; by occupying the southern Marianas, target date 15 June 1944; and by occupying the Palaus, target date 15 September 1944.

5. Occupation of Mindanao by MacArthur’s forces supported by the Pacific fleet, target date 15 November 1944.

6. Occupation of Formosa, target date 15 February 1945, or occupation of Luzon if necessary, target date 15 February 1945.73

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With this directive in hand, Admiral Nimitz and his subordinates could at last prepare their tactical plans in detail. The southern Marianas would be assaulted and the target date was to be 15 June. The largest amphibious operation yet to be undertaken in the Pacific was about to get under way.