UNITED STATES STRATEGIC BOMBING SURVEY

SUMMARY REPORT

(Pacific War)

WASHINGTON, D.C.

1 JULY 1946

UNITED STATES

GOVERNMENT PRINTING OFFICE

WASHINGTON : 1946

Foreword

The United States Strategic Bombing Survey was established by the Secretary of War on 3 November 1944, pursuant to a directive from the late President Roosevelt. It was established for the purpose of conducting an impartial and expert study of the effects of our aerial attack on Germany, to be used in connection with air attacks on Japan and to establish a basis for evaluating air power as an instrument of military strategy, for planning the future development of the United States armed forces, and for determining future economic policies with respect to the national defense. A summary report and some 200 supporting reports containing the findings of the Survey in Germany have been published. On 15 August 1945, President Truman requested the Survey to conduct a similar study of the effects of all types of air attack in the war against Japan.

The officials of the Survey in Japan, who are all civilians, were:

Franklin D'Olier, Chairman.

Paul H. Nitze,

Henry C. Alexander, Vice Chairmen.

Harry L. Bowman,

J. Kenneth Galbraith,

Rensis Likert,

Frank A. McNamee, Jr.,

Fred Searls, Jr.,

Monroe E. Spaght,

Dr. Louis R. Thompson,

Theodore P. Wright, Directors.

Walter Wilds, Secretary.

The Survey's complement provided for 300 civilians, 350 officers, and 500 enlisted men. Sixty percent of the military segment of the organization for the Japanese study was drawn from the Army, and 40 percent from the Navy. Both the Army and the Navy gave the Survey all possible assistance in the form of men, supplies, transport, and information. The Survey operated from headquarters in Tokyo, with subheadquarters in Nagoya, Osaka, Hiroshima, and Nagasaki, and with mobile teams operating in other parts of Japan, the islands of the Pacific, and the Asiatic mainland.

The Survey secured the principal surviving Japanese records and interrogated top Army and Navy officers, Government officials, industrialists, political leaders, and many hundreds of their subordinates throughout Japan. It was thus possible to reconstruct much of wartime Japanese military planning and execution, engagement by engagement and campaign by campaign, and to secure reasonably accurate data on Japan's economy and war production, plant by plant, and industry by industry. In addition, studies were made of Japan's over-all strategic plans and the background of her entry into the war, the internal discussions and negotiations leading to her acceptance of unconditional surrender, the course of health and morale among the civilian population, the effectiveness of the Japanese civilian defense organization and the effects of the atomic bomb. Separate reports will be issued covering each phase of the study.

In this Summary Report the civilian officials and directors of the Survey have not undertaken to write a history of the Pacific war, nor to apportion credit for victory among the various component Allied forces. They have undertaken, as civilians, to present an analysis of the factual material gathered by the Survey and their general appraisal thereof as to the future.

UNITED STATES STRATEGIC BOMBING SURVEY

SUMMARY REPORT

The attack on Pearl Harbor was designed around surprise, the range of carrier task forces, and the power of aircraft to sink surface vessels. It was executed with the loss of 29 Japanese pilots. Two days later, the Japanese found the British battleship, Prince of Wales, and the battle cruiser, Repulse, without air cover off Malaya and sent them to the bottom with the loss of 4 Japanese Navy medium bombers. Allied air power in the Philippines, Malaya, and the Dutch East Indies was virtually eliminated, mostly on the ground, in a matter of days. Those enormous areas, once local allied air power had been eliminated, were laid open to occupation in a matter of weeks, at a cost of less than 15,000 Japanese soldiers killed, and with the loss from all causes in the entire campaign of 381 Japanese planes.

As these achievements indicate, the Japanese started the war aware of the fact that major offensive action cannot be undertaken without local control of the air. They also appreciated the vulnerability to air attack of surface objectives, both on land and at sea. The Japanese failed, however, to appreciate the full scope and complexity of the requirements for continuing control of the air. The Japanese aircraft production program at the start of the war was inadequate, as the Japanese subsequently discovered, not only in relation to that of the United States, but even in relation to the capabilities of their own economy. Their planning and execution with respect to training, maintenance, logistics, technical development, intelligence and full coordination with their land and surface forces, were limited in relation to the requirements that subsequently developed. Japan's war plans did not contemplate, nor were its capabilities such that it could have contemplated, interference with the sustaining resources of United States air power.

December 7, 1941, found the United States and its Allies provocatively weak in the Pacific, particularly in land and carrier-based air power. The Allied air groups actually in the Pacific were not only few in number but, in large measure, technically inferior to those of the Japanese. The Japanese strength had been underestimated. Ninety P-40s and 35 B-17s in the Philippines could not be expected to check the Japanese push southward. Three of our seven aircraft carriers were in the Atlantic and one training in the Gulf of Mexico. Even at that time, however, we had begun to see, more clearly than the Japanese, the full scope of the basic requirements for air power. Our programs for training, production, maintenance, logistics, and intelligence were limited, not so much by a lack of concept as by the time required for their development and fulfillment.

How the original Japanese advance was stopped, how we achieved air superiority, at first locally, but subsequently more and more generally, and over areas deep within the one-time Japanese dominated areas, culminating finally in air supremacy over the Japanese home islands themselves, and how that air superiority was exploited, is the story of air power in the Pacific war and the subject matter of this Summary Report. The role of air power cannot be considered separately, however, from the roles of ground and naval forces nor from the broad plans and strategy under which the war was conducted.

JAPAN'S ORIGINAL STRATEGIC PLAN

Japan's governmental structure provided no effective civilian control of her Army and Navy. In the years between the 1931 invasion of Manchuria and the 1941 attack upon Pearl Harbor, the military cliques of Japan exerted a progressively tighter control over the foreign and domestic affairs of the nation. These cliques included groups within both the Army and Navy, but because of the repeated military successes of the Japanese Army in Manchuria and China and the prestige so acquired, and because of the more ambitious and aggressive nature of the Japanese Army leaders, the political position of the Army was ascendant to that of the Navy. The final decision to enter the war and to advance into the Philippines, the Dutch East Indies, Malaya, Burma and to the southeast was, however, made with the full concurrence and active consent of all important Japanese Army and Navy leaders and of almost all her important civilian leaders.

This decision to which the Japanese were, in effect, committed by mid-October 1941 was based upon the following evaluation:

a. The threat of Russia on the Manchurian flank had been neutralized by the decisive victories of Germany in Europe which might eventually lead to the complete collapse of the Soviet Union. b. Great Britain was in such an irretrievably defensive position that, even if she survived, her entire war-making potential would be spent in a desperate effort to protect her home islands. c. The forces which the United States and her allies could immediately deploy in the Pacific, particularly in the air, were insufficient to prevent the fully trained and mobilized forces of Japan from occupying within three or four months the entire area enclosed within a perimeter consisting of Burma, Sumatra, Java, northern New Guinea, the Bismarck Archipelago, the Gilbert and Marshall Islands, Wake, and from there north to the Kuriles. d. China, with the Burma Road severed, would be isolated and forced to negotiate. e. The United States, committed to aiding Great Britain, and weakened by the attack on Pearl Harbor, would be unable to mobilize sufficient strength to go on the offensive for 18 months to 2 years. During this time, the perimeter could be fortified and the required forward air fields and bases established. So strengthened, this perimeter would be backed by a mobile carrier striking force based on Truk. f. While the stubborn defense of the captured perimeter was undermining American determination to support the war, the Japanese would speedily extract bauxite, oil, rubber and metals from Malaya, Burma, the Philippines and the Dutch East Indies, and ship these materials to Japan for processing, to sustain and strengthen her industrial and military machine. g. The weakness of the United States as a democracy would make it impossible for her to continue all- out offensive action in the face of the losses which would be imposed by fanatically resisting Japanese soldiers, sailors and airmen, and the elimination of its Allies. The United States in consequence would compromise and allow Japan to retain a substantial portion of her initial territorial gains.

Certain civilian and naval groups were familiar with the United States, its industrial and technological potential, and probable fighting determination when aroused. They expressed doubts about a strategy which promised no conclusion to the war other than negotiation, and which thus might drag out interminably with consequent risk of defeat. The Navy, however, was gravely concerned about its declining oil supply after the United States and the British economic embargo of July 1941. Such civilians as were reluctant were overruled and went along with the more dynamic opinion.

None of the responsible Japanese leaders believed that within any foreseeable period of time Japan could invade the United States and dictate peace in the White House. Admiral Yamamoto's supposed boast that Japan would do so was in fact never made. These leaders furthermore felt that Japan's limited shipping would be strained to the utmost in providing logistic support for the plan adopted and would be wholly inadequate for any more ambitious program, unless the initial operations went unexpectedly well.

EXECUTION OF THE JAPANESE PLAN

In accordance with the above plan, the Japanese Army was given primary responsibility for conquering Malaya, Sumatra and Burma and, because of the limited range of its planes, for furnishing initial air support in northern Luzon only above 16º north latitude. The Japanese Navy was assigned primary responsibility, in addition to the attack on Pearl Harbor, for initially launching operations in the Philippines, Borneo, Celebes, Java, northern New Guinea, the Bismarck Archipelago and out to the Gilbert Islands and Wake. The Army was to assume control in the Philippines as soon as the landing forces were established ashore. On 7 December 1941 the Japanese army and Navy air forces were accordingly disposed as follows:





Army Unit Aircraft Strength Deployment Third Flying Division 550 Malayan Campaign. Fifth Flying Division 175 Philippines Campaign. First Flying Brigade 150 China. Second Flying Division 450 Manchuria (Reserve). First Flying Division 50 Japan. Total Army 1,375

Naval Unit Aircraft Strength Deployment Twenty-first and Twenty-third Air Flotillas 300 Philippines Campaign. Twenty-second Air Flotilla. 150 Malayan Campaign. Twenty-fourth Air Flotilla 50 Marshalls. Carrier Force (6 CVs) 400 Pearl Harbor. Combined Fleet 75 Seaplanes attached to surface vessels. Miscellaneous 275 Japan. Total Navy 1,250 Grand Total 2,625

The Japanese were not depending solely upon the volume of their air strength in these initial engagements, although they believed they possessed sufficient superiority in numbers over Allied air forces in the Pacific. More than on numbers, the Japanese relied on surprise and speed of advance, and upon the training and experience of their airmen. In 1941 the average first-line Japanese pilot had about 500 - 800 flying hours, and about 50 percent of Japanese Army pilots and 10 percent of Japanese Navy pilots had had actual combat experience in China or in border fighting with the Soviet Union in 1939. The carrier air groups were especially trained in shallow-water torpedo drops for the Pearl Harbor attack, and the Japanese Army air units were trained for support of ground operations in Malaya and the Philippines.

Facing the Japanese, the United States and its Allies had the following land-based air strength in the Pacific:





Country Aircraft Strength Deployment U. S. Army and Navy Air Forces 182 Philippines 12 Wake. 12 Midway. 387 Hawaii. Royal Netherlands East Indies Air Forces 200 Netherlands East Indies. Royal Air Force 332 Malaya. Royal Australian Air Forces 165 Australia, Solomons, Netherlands East Indies, and Malaya. Total Allied 1,290

The majority of these planes were of obsolete types.

These forces were quickly overwhelmed. Fifty percent of the planes were destroyed on the ground. Our three lightly supported aircraft carriers in the Pacific did not constitute a sufficient force to warrant their being risked in those operations.

Following the initial successes at Pearl Harbor, Malaya and in the Philippines, Wake and Guam were occupied in December, and Rabaul in January. The Japanese gained air superiority in Burma with the loss of 102 planes and, with troops specially trained for jungle fighting, occupied that area at a cost of 7,000 soldiers killed. At the end of 4 months of war, they had carried out the substance of their initial program and with greater ease than they had foreseen. Total merchant shipping losses were 51 ships. Much of the equipment which had originally been scheduled for movement into the southern islands was found to be unnecessary and was left behind in order to achieve greater speed. Certain of the Japanese leaders were concerned by the skillful and unexpectedly determined resistance of our ground forces in the Philippines. They attributed this in part to inefficient Japanese close-air support. But in some circles, the skill and determination with which our isolated forces conducted the defense was correctly assessed as an ominous cloud on the horizon.

JAPANESE OVEREXTENSION

The magnitude of these successes encouraged the more daring Japanese planners to consider expansion beyond the original perimeter. During their discussions, the Doolittle raid of 18 April 1942 struck Tokyo. Although the damage caused was inconsequential, the reach of the attack supported a growing feeling that the Japanese perimeter would gain in strength if it had greater defense in depth.

Accordingly a new plan was approved, providing for (a) an advance into the Solomons and Port Moresby, to be followed, if successful, by a further advance into New Caledonia, Samoa and the Fiji Islands, (b) the capture of Midway, and (c) the temporary occupation of the Aleutians. Accomplishment of such a program would cut off the line of communication between Australia and the United States, reduce the threat from Alaska,

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and deny the United States all major staging areas more advanced than Pearl Harbor.

By stretching and overextending her line of advance, Japan was committed to an expensive and exacting supply problem, she delayed the fortification of the perimeter originally decided upon, jeopardized her economic program for exploiting the resources of the area already captured, and laid herself open to early counter-attack in far advanced and, as yet, weak positions.

THE UNITED STATES PLAN BEFORE PEARL HARBOR

Prior to Pearl Harbor it had been decided that, in the event of war, Germany would have to be eliminated first, and that our initial role in the Pacific would, in large measure, be defensive. But Japan's offensive capabilities were underestimated; it was thought possible to hold the Malaya barrier, successfully engage the Japanese fleet in the Central Pacific, and lay the foundations for an eventual advance against Japan itself. The United States plan had little basis in reality. With the forces then available no adequate plan of defense was possible. The loss of relatively antiquated battleships at Pearl Harbor did not substantially reduce the actual combat capabilities of our Navy at that time as opposed to the Japanese Navy with its superiority in aircraft carriers and battle line speed. To have implemented an adequate plan in December 1941 would have required better intelligence regarding Japanese intentions and capabilities, an earlier understanding of the predominant and indispensable role of air strength and full public support for the necessary appropriations, well before the actual outbreak of war.

As it developed, all that we could do prior to May 1942, apart from the resistance of our isolated forces in the Philippines and sporadic carrier and land-based air raids, was to build up our strength in Australia and the islands lying between Pearl Harbor and Australia, while bringing to fruition our training and production programs.

TURNING THE TIDE

United States preparations were still inadequate when it became evident that the Japanese intended to advance south from the Bismarck Archipelago, and thus threaten our communications with Australia. It was decided nevertheless to attempt to hold Port Moresby and a line north of Espiritu Santo and the Fiji Islands. Exceptional intelligence gave us advance information that a group of transports, protected by the Japanese carrier Shoho and by a covering force including two other carriers, was on its way to occupy Port Moresby in May 1942. This information enabled us to concentrate at the appropriate point two of our four carriers then available in the Pacific (one had come to the Pacific from the Atlantic, but two were returning from the Doolittle raid on Tokyo), and to sink the Shoho by torpedo-plane and dive-bomber attack. In the ensuing air engagement with the covering force, we damaged one of the Japanese carriers in that force, but lost the Lexington. The Japanese force had two carriers left to our one, but their air groups had been badly depleted. The transports turned back from Port Moresby to return to Rabaul and, for the first time, the Japanese advance had been checked. The combat in this Battle of the Coral Sea was entirely carrier air action.

Similar intelligence provided advance information as to the Japanese move toward Midway in June. In this case, the transports were supported by an advance striking force, including the most powerful surface forces yet assembled in the war and four of Japan's remaining eight operational carriers. An additional Japanese carrier was in a supporting force farther to the north. Again only weaker forces were available to the United States three carriers, the Enterprise, Yorktown, and Hornet, the only ones available for combat action in the Pacific at that time, were rushed to the attack. Our planes located the Japanese fleet and sank three of the enemy carriers, and so damaged the fourth that she subsequently fell an easy prey to a United States submarine. Deprived of its carriers the Japanese Fleet was forced to retire despite its preponderance in heavy ship strength. Survey interrogations of surviving officers from the Japanese carriers indicate that they were sunk by carrier-based dive bombers. Two-thirds of the pilots on the Japanese carriers sunk were rescued by Japanese destroyers. Some of the Japanese carrier-based planes discovered our carriers and succeeded in damaging the Yorktown so seriously that she went dead in the water and was sunk by a Japanese submarine. Except for the finishing off of stragglers by submarines, the combat in this engagement was entirely air action.

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Immediately after Midway, the Japanese had 4 carriers fit for action, shortly to be joined by a fifth; but of these only 1 was large. In addition, they had 6 carriers under repair or construction. The United States had 3 large carriers operational in the Pacific and 13 carriers, and 15 escort carriers, either being readied for operation, or under construction. The Japanese Navy, thereafter, was hobbled by its weakness in the air, and could engage our forces only at night or under cover of land-based air until that air strength was rebuilt. A balance of naval air power in the Pacific, and as a consequence a balance of naval power as a whole, was thus achieved at Midway.

The scene of intense conflict shifted back to the islands south of Rabaul, the seas surrounding them, and the air over both. The Japanese had determined to renew their efforts to capture Port Moresby, if necessary by the overland route from the northern shore of New Guinea, and were constructing air fields in the Solomons. The United States Joint Chiefs of Staff ordered a two-pronged attack; one directed toward northern New Guinea from Port Moresby, the other up the chain of the Solomon Islands beginning with Guadalcanal; both with the final objective of capturing Rabaul. General MacArthur and Admiral Ghormley considered the forces available to them inadequate, but, in view of the importance of maintaining the line of communication with Australia, they were ordered to go ahead with what they had. A test of the Japanese perimeter thereby developed earlier than the Japanese had expected.

While the Southwest Pacific command was building air fields in northern Australia, Port Moresby and Milne Bay, the Japanese landed, on 21 July 1942, at Buna on the north coast of New Guinea opposite Port Moresby and infiltrated over the Owen Stanley Range. Their lines of communications were cut by air attacks, their advance columns strafed and their attack held and pushed back by ground forces, in part supplied by air. The Japanese testify that they were unable to reinforce this attack to the extent they had planned because of developments at Guadalcanal.

On 7 August 1942, a surprise landing was made on Guadalcanal. Three United States carriers gave initial air support and the Marines who landed quickly captured the air field (later named Henderson Field) which was under construction by the Japanese. Interrogation of the senior Japanese commanders involved in the Solomons campaign indicates that they originally misjudged the strength of our attack and sent in only one reinforcement battalion of 500 men on fast destroyers from Truk. After this battalion was virtually destroyed, they sent in 5 more which again were not quite sufficient. Finally, they attempted to send in whole divisions. Thirty thousand troops were landed but, by that time, it was too late. Local control of the air provided by planes based on Henderson Field made it possible, but barely possible, to defend our unloading supply ships in the daytime, and made it impossible for the Japanese to land, except at night and then under hazardous and unsatisfactory conditions. The efforts of the Japanese to run in reinforcements at night, and at times to shell our shore installations, resulted in a series of night naval surface engagements which caused heavy losses to both sides. Our air strength was initially limited, was maintained by desperate and irregular reenforcement, and at one time was reduced by enemy naval bombardment to only 5 operational airplanes. The Japanese constructed a chain of air fields between Guadalcanal and Rabaul, and attempted to raid our ships and installations. In the air actions, however, they suffered increasingly heavy losses, not merely in numbers, but also in proportion to United States losses. The Japanese paint a vivid picture of the intolerable position in which inability to achieve air control placed them. General Miyazaki testified that only 20 percent of the supplies dispatched from Rabaul to Guadalcanal ever reached there. As a result the 30,000 troops they eventually landed on Guadalcanal lacked heavy equipment, adequate ammunition and even enough food, and were subjected to continuous harassment from the air. approximately 10,000 were killed, 10,000 starved to death, and the remaining 10,000 were evacuated in February 1943, in a greatly weakened condition.

By the end of 1942, the most serious of the Japanese attempts to drive us off Guadalcanal had been thrown back and Allied operations to capture the Buna area were drawing to a close. We were securely established in these critical areas and had gradually built up local superiority in all arms, air, ground and sea. Our losses had been heavy. The Japanese, however, had suffered a crucial strategic defeat. Their advance had been stopped, their strategic plan fatally upset, many of their best pilots lost, and Allied forces firmly installed in

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positions in the Solomons and New Guinea, which threatened the anchor of their perimeter at Rabaul. In opposing this threat, the Japanese committed in piecemeal fashion and lost all of their fully trained Navy air units, including those rescued at Midway, and a portion of their best Army air units. The Japanese never fully recovered from this disaster, the effects of which influenced all subsequent campaigns. For the first time, the few Japanese who had all the facts at their disposal appreciated the seriousness of the situation. Greatly expanded programs for the training of pilots and the production of aircraft, radar and communications equipment, antiaircraft guns and ammunition, cargo vessels and tankers, were drawn up, but time was required to implement them.

The initiative had passed to the United States.

FACTORS DETERMINING THE NATURE OF THE SUCCEEDING CAMPAIGN

After the engagements of 1942, certain basic lessons of combat in the Pacific theater had been learned. It appeared that the widely spread Japanese positions could be bypassed or captured, provided that air superiority in the necessary areas was achieved, and provided the required naval support, adequate assault craft, properly trained troops, and full logistics were available. Major preparations were required before decisive advances could be undertaken. In the meantime, however, unremitting pressure could be kept on the Japanese.

Due to the geography of the Empire, the Japanese ground forces depended for their effectiveness upon overseas support in all areas except the main home islands, and even there, overseas imports of raw materials were required. In China, Korea, and Manchuria, an overwater lift to the mainland was involved, and shipping was employed in the supply of troops in Malaya, Burma, and continental regions of the southwest. The islands of the eastern perimeter were completely dependent on supply by sea. Deployed as the Japanese ground forces were on detached land masses, dependent on inadequate shipping, their defeat was necessary only at points of United States choosing. The bulk of them could be bypassed.

The Japanese Navy, which included two 64,000 ton battleships of great fire-power and speed, had lost both operational freedom and striking power due to its limited carrier-based air strength. By late 1943, the United States had available sufficient carriers for clear-cut superiority in the air, and had added to the fleet sufficient modern heavy ships to offer reasonable protection against the Japanese surface strength were it to be committed under bad weather or other conditions limiting the degree to which our superiority in the air could be brought to bear. The ability to destroy the Japanese surface forces, if they were committed, was essential. Furthermore, their destruction would increase the freedom and ease of our further advances.

The limitations imposed by geography and the range of Japanese land-base planes made it impossible for the Japanese to achieve sufficient mobility of their land-based air forces to concentrate their full air strength against us at any crucial point, prior to the invasion of the Philippines and Okinawa. Most of the island atolls were too small to support the necessary air fields, and in New Guinea, the Solomons and the Marianas, logistic, air field construction and ferrying problems made such concentration impossible. Even within the limits so imposed, poor Japanese staff work and tactics resulted in piecemeal employment of their available air strength. Over and above these weaknesses, Japanese aircraft production, pilot training and maintenance were so far behind our own that it was evident that general air superiority over the Japanese could be achieved. This objective received first priority.

The Japanese shipping target was immediately available. In the first year of the war, submarines, capable of long-range offensive action inside the Japanese perimeter, sank more than 10 percent and air planes 4 percent of the merchant ship tonnage which Japan possessed at the start of the war. The strangulation of Japanese overwater movement, thus begun, could be continued both by the submarine and by attack from the air.

Japanese industry and her home population would not be within effective striking distance of United States long-range bombers until bases within 1,500 nautical miles of Japan could be secured.

An advance to strategic positions across the Pacific would give us bases from which to complete the interdiction of Japan's overwater shipping, to mount large scale air attacks against the Japanese home islands, and to prepare for an invasion of the home islands themselves.

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THE ADVANCE ACROSS THE PACIFIC

Such was the situation when the United States began its widespread offensive. While major preparations were still in progress, and the heavy attrition of the Solomons and eastern New Guinea campaign was chewing up Japan's best air groups and depleting her shipping and supplies, the first long-range moves in the advance across the Pacific were undertaken. These began unostentatiously with the assault against Attu, on the northern flank of the Japanese defense perimeter in May 1943. On the southern flank, the offensive continued with an advance to Munda in June, to Salamaua, Lae, and Finschafen on New Guinea in September, and Bougainville in November 1943. In the Central Pacific it began with the assault on the Gilbert Islands in November 1943.

Thereafter, the amphibious advance toward Japan continued over two routes. One was up the north coast of New Guinea to the Philippines, the other across the Central Pacific through the Marshalls to the Marianas and Palau and then subsequently on to Iwo Jima and Okinawa. Basically, the advance was for the purpose of projecting United States power to points which cut Japan's supply lines to the south and were within striking range of the Japanese home islands. Objectives were seized for one or more of four purposes: To provide forward air fields so that shore-based aircraft might maintain and project forward United States control of the air; to furnish advance bases for the fleet; to secure land areas for the staging of troops in succeeding advances; and, in the case of the Marianas, to provide bases for long-range air attacks on the Japanese home islands.

In the New Guinea area it continued to be possible to choose objectives for our advance where the enemy was weak, to seal off these objectives from enemy reinforcement and cover advances to them with land-based air, and, in certain instances, to supply the operation entirely by air. Marilinan, Nadzab and other inland bases on New Guinea, which eventually had complements as large as 25,000 men, were occupied, supplied and later moved forward entirely by air. The range of these advances was limited to the combat radius of fighter aircraft.

For long-range amphibious advances against strongly defended positions a typical pattern developed. Japanese bases flanking the United States objective were smothered by a concentration of air power. Such bases as were within reach were hammered by shore-based air. Carrier-based air and available shore-based air softened the area to be occupied, and as the amphibious force moved up, fast carriers advancing beyond the objective struck swift blows at all positions which could threaten the objective area. With close air support from both escort and fast carriers and a concentration of gunfire from combatant ships of the support force, an amphibious assault over the beaches was made. The objective was secured under air support and cover from the carriers, which were not withdrawn until air fields ashore could be prepared and activated.

The amphibious steps along the two principal lines of advance toward Japan were well timed and mutually supporting, even though concentration on one line might have been more rapid. The losses inflicted at Rabaul, primarily by land-based planes from the Solomons and New Guinea, forced the Japanese to the decision not to support their garrisons in the Gilberts, were they to be attacked. The Central Pacific advance into the Gilbert and Marshall Islands in late 1943 and early 1944, and the threat of a fast carrier task force strike against Truk, which eventuated in February 1944, cleared the Japanese Fleet from the New Guinea flank and assisted the move into the Admiralties in March 1944 and the long step up the coast of New Guinea to Hollandia in April 1944, which was followed by a further advance to Wakde and Biak in May 1944. When the Japanese attempted reinforcement of northern New Guinea, the Central Pacific advance into the Marianas in June 1944, forced the abandonment of the operation. The Japanese committed their carriers in the defense of the Marianas, and lost in the Battle of the Philippines Sea practically all their carrier-based air groups sufficiently trained for combat, as well as three carriers sunk. Noemfoor was taken while the Japanese were preoccupied in the Marianas. Landings on Morotai were timed with those in the Palaus.

While the landings in the Palaus were in progress, the fast carrier task force struck Japanese aircraft, air fields and shipping in the Philippines. Preliminary to the Leyte operation, the fast carrier task force with a concentration of more than 1,000 planes attacked Okinawa, Formosa and the Philippines, exacting a large toll of Japanese air power. B-29 strikes from China against air installations

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on Formosa supported this operation. The landing at Leyte Gulf in the Philippines was correctly assessed by the Japanese as their last opportunity, short of a defense of the Japanese home islands, to throw in all their available forces to check the United States advance in a decisive engagement.

Three days after the landing at Leyte they committed their entire fleet in a three-pronged attack. The plan contemplated that a carrier force advancing from the north would draw off our main strength, while heavy surface forces approaching through Surigao and San Bernardino Straits and covered by Japanese Army and Navy planes from airfields in the Philippines would destroy our transports and supporting strength off the landing beach. The Japanese strategy succeeded in drawing off our main strength to the north. The southern Japanese force was destroyed in a night surface engagement in Surigao Straits. Four carriers in the northern force were sunk off Luzon. Although one of its super-battleships had been sunk by torpedo plane attack, the central force penetrated close to our transports still possessed of overwhelming surface strength. The Japanese commander of the central force testified to the Survey that lack of expected land-based air support and air reconnaissance, fear of further losses from air attack, and worry as to his fuel reserves induced him to withdraw. As a result of this decision to retire, the Japanese failed to secure the objective for which catastrophic losses had been risked and suffered by the other two Japanese forces.

In the ensuing actions in the Philippines, the Japanese lost all the troops and supplies deployed there, plus three and one-half divisions sent in from China and Manchuria. In the Philippines campaign as a whole they committed and lost 9,000 planes. On 1 March 1945, the Japanese decided to send no further supplies to their ground forces outside of the home islands. Except for delaying actions they had been forced to concentrate solely on defense against invasion.

While the liberation of the Philippines was being completed, the Central Pacific forces made the difficult moves into Iwo Jima and Okinawa.

CHINA-BURMA-INDIA

The allied strategic plan contemplated that the actual defeat of Japan would be accomplished by operations in the Pacific. In the meantime, however, it was essential to defend India and to assist China. We could not afford to make substantial forces available. Our contribution in the China-Burma-India theater was almost entirely air and logistic support. The geography of the theater was such that overland transportation was virtually impossible beyond the Indian bases. As a consequence, the air in the China- Burma-India theater was called upon, not only to give protection against and to fight down enemy air and disrupt Japanese shipping and rail transportation, but also to transport the men and supplies for all forces and provide much of the fire power even in ground operations.

Full superiority over Japanese air forces was gradually attained. British ground forces at Imphal which had been surrounded by an attacking Japanese force were supplied by Allied air. The Japanese force was in turn isolated by air attack and destroyed. The troops that liberated Burma were moved, supplied, and supported by air. Japanese logistics in Burma and China were disrupted. China was kept in the war.

Over 1,180,000 tons of supplies and equipment and 1,380,000 troops were transported by air. The air movement over the "hump" between India and China attained a peak rate of 71,000 tons in 1 month.

In the fall of 1943 it was decided to attack Japanese industrial targets in Manchuria and Kyushu with B-29s flying from advanced bases in China. When this decision was reached, Guam, Saipan and Tinian had not yet been captured, and no other bases were available sufficiently close for direct strikes at the Japanese "Inner Zone" industries. The principal bottleneck in air operation in China was the transportation from India by air of the necessary supplies, most of which were allocated to supplying Chinese ground forces. As a result, the B-29s had sufficient supplies for only a small number of strikes per month. Data secured by the Survey in Japan established that these strikes caused more severe damage to the Manchurian steel plants selected as targets than assessment of aerial photography had revealed. With the benefit of hindsight, however, it appears that the overall results achieved did not warrant the diversion of effort entailed and that the aviation gasoline and supplies used by the B-29s might have been more profitably allocated to an expansion of the

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tactical and antishipping operations of the Fourteenth Air Force in China. The necessary training and combat experience with B-29s provided by this operation might have been secured through attacks on "Outer Zone" targets, from bases more easily supplied. In November 1944, long-range bomber attacks from Guam, Saipan and Tinian were initiated. The B-29s based in China were transferred to these bases in April 1945.

By March 1945, prior to heavy direct air attack on the Japanese home islands, the Japanese air forces had been reduced to Kamikaze forces, her fleet had been sunk or immobilized, her merchant marine decimated, large portions of her ground forces isolated, and the strangulation of her economy well begun. What happened to each of these segments of Japan's vanishing war potential is analyzed in the following sections.

ELIMINATION OF JAPANESE CONVENTIONAL AIR POWER

Japanese production of aircraft of all types rose from an average of 642 planes per month during the first 9 months of the war to a peak of 2,572 planes per month in September 1944. The rise was particularly great during 1943, after the Japanese had learned the lessons of the 1942 campaigns. Aggregate production during the war was 65,300 planes.

Japanese army and navy plane losses from all causes, both combat and noncombat, rose from an average rate of some 500 planes per month in the early months of the war to over 2,000 per month in the latter months of 1944. Aggregate losses during the course of the war were of the order of magnitude of 50,000 planes, of which something less than 40 percent were combat losses, and something over 60 percent were training, ferrying, and other noncombat losses.

The Japanese were thus able to increase the numerical strength of their air forces in planes, in almost every month of the war. Numerical strength increased from 2,625 tactical planes at the outbreak of the war to 5,000 tactical planes, plus 5,400 Kamikaze planes, at the time of surrender.

Aggregate flying personnel increased from approximately 12,000 at the outbreak of the war to over 35,000 at the time of surrender.

United States aircraft production and pilot training exceeded the Japanese totals by wide margins, but only a portion of this strength could be deployed to the Pacific. United States first line strength in the Pacific west of Pearl Harbor increased from some 200 planes in 1941 to 11,000 planes in August 1945. It was not until late 1943 that we attained numerical superiority over the Japanese air forces in the field. Even in 1942, however, the relatively few United States air units in the Pacific were able to inflict greater losses than they sustained on the numerically superior Japanese. Aggregate United States plane losses during the course of the Pacific war, not including training losses in the United States, were approximately 27,000 planes. Of these losses 8,700 were on combat missions; the remainder were training, ferrying and other noncombat losses. Of the combat losses over 60 percent were to antiaircraft fire.

As previously stated, Japanese pilots at the outbreak of the war were well trained. The average Army pilot had some 500 hours before entering combat and Navy pilots 650 hours. These experienced pilots were largely expended during the bitter campaigns of the opening year and a half of the war. The Japanese paid far less attention than we did to the protection, husbanding and replacement of their trained pilots, and were seriously hampered in their training program by a growing shortage of aviation gasoline. Average flying experience fell off throughout the war, and was just over 100 hours, as contrasted to 600 hours for United States pilots, at the time of surrender. Inadequately trained pilots were no match for the skilled pilots developed by the United States.

At the time of the initial Japanese attack, Japanese fighter planes, although less sturdily built, more vulnerable and weaker in fire power than the United States fighters, had certain flight characteristics superior to those of United States fighters then available in the Pacific. The Japanese improved the quality of their planes during the war, greatly increased the power of their aircraft engines, ultimately exceeded United States fighters in fire power and had first-class aircraft in the design and experimental stage at the end of the war. They lacked, however, the widespread technical and industrial skill to match the United States in quantity production of reliable planes with increased range, performance and durability. After the initial campaigns, the United States always enjoyed superiority in the over-all performance of its planes. By American standards, the Japanese never

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fully appreciated the importance of adequate maintenance, logistic support, communications and control, and air fields and bases adequately prepared to handle large numbers of planes. As a result, they were unable to concentrate any large percentage of their air strength at any one time or place. Neither did they appear to have the ability to control large formations in the air with any degree of efficiency.

Local air control and its tactical exploitation the Japanese understood and achieved in their early offensives.

But along with all other military powers prior to the war, the Japanese had failed fully to appreciate the strategic revolution brought about by the increased capabilities of air power. The ability to achieve general and continuing control of the air was not envisaged as a requirement in their basic war strategy, as was the planned destruction of the United States Fleet. Had this basic requirement been well understood it is difficult to conceive that they would have undertaken a war of limited objectives in the first place. Once started on a strategic plan which did not provide the means to assure continuing air control, there was no way in which they could revise their strategy to reverse the growing predominance in the air of a basically stronger opponent who came to understand this requirement and whose war was being fought accordingly.

CONVERSION OF JAPANESE AIR FORCES TO KAMIKAZE FORCES

By the summer of 1944, it had become evident to the Japanese air commanders that there was no way in which they could equal the United States air arms at any point. Their losses were catastrophic, while the results which they were achieving were negligible. The one and only asset which they still possessed was the willingness of their pilots to meet certain death. Under these circumstances, they developed the Kamikaze technique. A pilot who was prepared to fly his plane directly into a ship would require but little skill to hit his target, provided he got through the intervening screen of enemy fighters and antiaircraft fire. If sufficient Japanese planes attacked simultaneously, it would be impossible to prevent a certain proportion from getting through. Even though losses would be 100 percent of the planes and pilots thus committed, results, instead of being negligible, might be sufficient to cause damage beyond that which we would be willing to endure.

From October, 1944, to the end of the Okinawa campaign, the Japanese flew 2,550 Kamikaze missions, of which 475, or 18.6 percent were effective in securing hits or damaging near misses. Warships of all types were damaged, including 12 aircraft carriers, 15 battleships, and 16 light and escort carriers. However, no ship larger than an escort carrier was sunk. Approximately 45 vessels were sunk, the bulk of which were destroyers. The Japanese were misled by their own inflated claims of heavy ships sunk, and ignored the advice of their technicians that a heavier explosive head was required to sink large ships. To the United States the losses actually sustained were serious, and caused great concern. Two thousand B-29 sorties were diverted from direct attacks on Japanese cities and industries to striking Kamikaze air fields in Kyushu. Had the Japanese been able to sustain an attack of greater power and concentration they might have been able to cause us to withdraw or to revise our strategic plans.

At the time of surrender, the Japanese had more than 9,000 planes in the home islands available for Kamikaze attack, and more than 5,000 had already been specially fitted for suicide attack to resist our planned invasion.

DESTRUCTION OF THE JAPANESE FLEET

As stated earlier in this report Japan started the war with 10 carriers. Six were sunk during the engagements of 1942. The Japanese during the course of the war constructed or converted from other types of ships a total of 17 additional carriers including 5 escort carriers; of the conversions one was made on a Yamoto-class battleship hull and two, carriers only in part, were the result of removing the after turrets of battleships and installing small hangers and launching decks. Due to the loss of their trained carrier air groups in 1942-43 and the time required to train new ones, the Japanese did not commit their carriers again until 1944. In the engagements of that year the Japanese lost 7 carriers without themselves securing appreciable results. Seven more were lost in home waters to submarine or air attack. All Japanese carriers sunk were lost either to our carrier-based aircraft or to submarines with the exception of one which was finished off by surface

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vessels after it had been mortally damaged by carrier airplanes.

The Japanese had two Yamato-class battleships, each of 64,000 tons, armed with 18-inch guns and minutely compartmented, which were more powerful than any United States battleship. One was sunk in the Sibuyan Sea, the other south of Kyushu, both by carrier torpedo-planes.

Japan began the war with 381 warships aggregating approximately 1,271,000 tons. An additional 816 combat ships totaling 1,048,000 tons were constructed during the war. Five hundred and forty-nine ships of all types and sizes, totaling 1,744,000 tons were sunk. Approximately 1,300,000 tons of Japanese warships in the carrier, battleship, cruiser and destroyer categories were included in the aggregate tonnage sunk. Of this total roughly 625,000 tons were sunk by Navy and Marine aircraft, 375,000 tons by submarines, 183,000 tons by surface vessels, 55,000 tons by Army aircraft, and 65,000 tons by various agents. Only 196,000 tons in these categories remained afloat at the end of the war. The tonnage sunk by surface ships was principally in night actions. A shortage of Japanese destroyers after 1943 and inadequate Japanese air antisubmarine measures contributed to the successes of United States submarines against the Japanese fleet.

After the liberation of the Philippines and the capture of Okinawa, oil imports into Japan were completely cut off; fuel oil stocks had been exhausted, and the few remaining Japanese warships, being without fuel, were decommissioned or were covered with camouflage and used only as antiaircraft platforms. Except for its shore-based Kamikaze airforce and surface and undersea craft adapted for anti-invasion suicide attack, the Japanese Navy had ceased to exist.

DESTRUCTION OF THE JAPANESE MERCHANT FLEET

Japan's merchant shipping fleet, was not only a key link in the logistical support of her armed forces in the field, but also a vital link in her economic structure. It was the sole element of this basic structure which was vulnerable to direct attack throughout a major portion of the war.

Japan entered the war with some 6,000,000 tons of merchant shipping of over 500 tons gross weight. During the war an additional 4,100,000 tons were constructed, captured or requisitioned. Sufficient information was secured by the Survey in Japan concerning this 10,100,000 tons to tabulate ship by ship, (a) the name end tonnage, (b>) the date, location; and agent of sinking or damage, and (c) the present condition and location of such ships as survived. The sources from which evidence was obtained were in some respects conflicting. Where possible these conflicts have been resolved. The Joint Army and Navy Assessment Committee has tentatively arrived at similar results and is continuing its efforts further to refine the evidence. The Survey believes that the figures included in the following breakdown will not differ significantly from the final evaluation of the Joint Army and Navy Assessment Committee.

Eight million nine hundred thousand tons of this shipping were sunk or so seriously damaged as to be out of action at the end of the war. Fifty-four and seven-tenths percent of this total was attributable to submarines, 16.3 percent to carrier based planes, 10.2 percent to Army land-based planes and 4.3 percent to Navy and Marine land-based planes, 9.3 percent to mines (largely dropped by B-29s), less than 1 percent to surface gunfire, and the balance of 4 percent to marine accidents.

Due to their ability to penetrate deeply into enemy-controlled waters, submarines accounted for approximately 60 percent of sinkings up until the final months of the war. During 1941, carrier task forces made deep sweeps which accounted for large numbers of ships. After April, 1945, when Japanese shipping was restricted to the Korean and Manchurian runs and to shallow inland waters, mines dropped by B-29s in Japanese harbors and inland waterways accounted for 50 percent of all ships sunk or damaged. In isolating areas of combat from ship-borne reinforcements land-based aircraft also sank large numbers of barges and vessels smaller than 500 tons gross weight, not included in the tabulation prepared by the Survey.

In the Survey's opinion those air units which had anti-shipping attacks as their prime mission and employed the required specialized techniques, equipment and training achieved against ships the best results for the effort expended.

The Japanese originally allocated two-thirds of their shipping fleet to the logistic support of their military forces in the field. They expected that

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after their original advance had been completed they would be able to return increasing numbers of ships to the movement of raw materials for their basic economy. After the beginning of the Guadalcanal campaign, however, they were kept under such constant and unexpected military pressure that the contemplated returns after that date were never possible.

Up to the end of 1942, ship sinkings exceeded new acquisitions by a small margin. Thereafter, the aggregate tonnage sunk increased far more rapidly than could be matched by the expansion of the Japanese shipbuilding program. The size of the usable fleet thus declined continuously and at the end of the war amounted to little more than 10 percent of its original tonnage. The Japanese belatedly attempted to build up a convoy system, to re-route freight movements to rail lines, and to abandon more distant sources of supply, but these measures acted only as palliatives and not as cures. Furthermore, convoying and re-routing decreased the freight moved per ship by a factor amounting to 43 percent in the closing months of the war. In 1944 tanker losses became particularly heavy and were thereafter the first concern of the Japanese shipping authorities.

The basic economic consequences of ship sinking will be discussed in a later section. From the standpoint of the Japanese armed forces in the field it will be noted that 17 percent of army supplies shipped from Japan were sunk in 1943, 30 percent in 1944, and 50 percent in 1945. A shortage of fleet tankers was a continuing limitation on the mobility of the Japanese fleet and contributed to its defeat in the two crucial battles of the Philippine Sea. Inadequate logistic support, due in large part to lack of shipping, was one of the principal handicaps of the Japanese air forces.

Attacks by submarines, long-range search and attack planes, mines, and carrier and land-based planes were mutually supporting and complicated the Japanese defenses. Long-range air search found targets for the submarines; convoying which offered some protection against submarines increased the vulnerability to air attack; ships driven into congested harbors in fear of submarines were easy prey for carrier strikes; and mines helped to drive ships out of shallow water into waters where submarines could operate. Had we constructed more submarines, earlier concentrated on tankers and more fully coordinated long-range air search and attack missions with submarine operations, the ship sinking program might have been even more effective.

DESTRUCTION OR ISOLATION OF JAPANESE GROUND FORCES

The Japanese built up their army ground forces from a strength of approximately 1,700,000 at the outbreak of war, to a peak strength of approximately 5,000,000. Japanese army medical records indicate that the aggregate number deployed in the Solomons, New Guinea, Marshalls, Gilberts, Carolines, Marianas, Philippines, Okinawa, Iwo Jima, and the Aleutians was approximately 668,000, of whom 316,000 were killed in action; some 220,000 were deployed in Burma, of whom 40,000 were killed; and 1,100,000 were deployed in China, of whom 103,000 were killed. Most of the remainder were in Manchuria, Korea, or the home islands, and did not actively participate in the decisive campaigns of the war.

The strategy of our advance and the limitations imposed on Japanese overwater transportation became such that the Japanese could concentrate only a small portion of their available Army ground forces strength at any of the critical island positions which we determined to capture. Japanese soldiers were unique in their willingness to face death and endure hardships. At every point where our Army or Marine forces engaged the Japanese on the ground after 1942, we enjoyed full air superiority. In every instance, except Ormoc in the Leyte campaign, we had eliminated Japanese ability to reinforce the critical area with either men or supplies. At Ormoc the Japanese were able to land 30,000 troops, but these reinforcements arrived piecemeal over too long a period of time to be effective and many of the transports were sunk prior to unloading heavy equipment. In every instance where the Japanese had prepared defenses in a landing area these had been softened up by aerial bombardment and usually by naval shelling as well. It often proved impossible, however, to destroy more than a small percentage of the defending Japanese soldiers in preliminary softening up operations of even the greatest intensity. The Japanese were dug in, in tunnels, trenches and caves which were hard to find and often impossible to destroy, either by bombing or by naval shelling. Most of their fixed artillery positions were eliminated, but even some of these survived. The

weight of fire on the immediate invasion beaches was generally such that the Japanese retired a short distance inland, but once we advanced beyond the beaches, it became necessary to destroy the remaining Japanese in costly close-range fighting. It was demonstrated, however, that Japanese resistance was effectively weakened and our casualties lighter when the appropriate weapons were employed with sufficient weight and accuracy in both preliminary softening up operations and subsequent close support.

A Japanese estimate indicates that in the southern regions, approximately 25 percent of their combat deaths resulted from aerial bombardment, 58 percent from small arms fire, 15 percent from artillery, and the remaining 2 percent from other causes.

In those places where it was essential to eliminate Japanese ground resistance in close-range fighting, great precision had to be developed in air-support operations in order to be certain not to hit our own troops, and to assure hits on the small targets which the critical Japanese positions presented. This required highly specialized training and the closest coordination between the ground and air forces through an intricate system of ground and air observers and unified control by ground-ship-air radio communication. In the Pacific war this system was continuously improved by the Navy and Marines in connection with succeeding amphibious operations against strongly defended positions and reached a high degree of effectiveness. In the Philippines campaign, the Army air forces employed comparable techniques, and General Yamashita has testified to his feeling of complete helplessness when confronted with this type of opposition.

In the Southwest Pacific, it often proved possible to effect landings at lightly held positions, and thus bypass large bodies of enemy ground forces. In the Central Pacific, many of the islands the Japanese expected us to attack were bypassed, and the garrisons left to wither and die. Survey examination of the bypassed islands in the Pacific and interrogation of the Japanese survivors confirmed their intolerable situation. Their planes and ground installations were destroyed by air attack. Cut off from any supplies or reinforcements, except occasionally by submarine, their food ran out. On certain of the islands, Japanese actually ate Japanese. It appears, however, that our air attacks on these bypassed positions were often continued longer and in greater weight than was reasonably required or profitable.

THE JAPANESE ECONOMY PRIOR TO SUSTAINED DIRECT AIR ATTACK

The orientation of the Japanese economy toward war began in 1928, and continued with increasing emphasis during the Manchurian and Chinese campaigns. By 1940, total production had arisen by more than 75 percent; heavy industrial production by almost 500 percent; and 17 percent of Japan's total output was being devoted to direct war purposes and expansion of her munition industries, as against 2.6 percent at that time in the United States. Construction of industrial facilities in these years assumed -- for the Japanese conditions -- gigantic proportions. Her aircraft, aluminum, machine tool, automotive, and tank industries were erected from almost nothing during this period.

This industrial expansion was based and depended on the availability of raw materials. Great efforts were devoted to the increase of raw material output in the home islands. In some respects, major results were achieved. Coal production in Japan rose from 28,000,000 tons in 1931 to 55,600,000 tons in 1941. Domestic iron mining made considerable progress. Nevertheless, no country could have been farther from self-sufficiency, with respect to raw materials, than Japan. The development of basic material sources on the continent of Asia constituted almost the central issue of Japan's economic policy during this period.

Although progress in Manchuria and China helped significantly to alleviate Japan's raw material shortages in coking coal, iron ore, salt and foods, insufficiency of raw materials continued to be the most important limiting factor on Japanese industrial output. Negligible quantities of oil and no bauxite sources existed within Japan's "Inner Zone." Output of aluminum ingots had risen from 19 tons in 1933 to 71,740 in 1941, 90 percent of which was produced from bauxite imported from the Dutch East Indies. Plans to develop a synthetic oil industry failed to yield significant results and Japan was almost wholly dependent on oil imports from the United States or the Dutch East Indies. A similar dependence on imports existed for rubber, ferro-alloys such as manganese,

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chrome, nickel, cobalt and tungsten, and for non-ferrous metals such as tin, lead, and mercury.

Pending seizure and economic exploitation of the oil and bauxite resources of the southern area, stock piling of these vital materials was a necessity. By the end of 1941, bauxite stocks of 250,000 tons, constituting a 7 months' supply, and 43,000,000 barrels of oil and oil products were stored in Japan.

Considering the economic performance of the decade, one cannot but be impressed by the intensity of the effort and the magnitude of the results. Nonetheless, Japan remained with an economy having approximately 10 percent of the potential of the United States economy. It was desperately vulnerable to attack on its shipping. Having a comparatively small, newly developed industry, it had to work without much cushion of under-utilized physical plant capacity. Having had little experience with mass production, the country had no opportunity to build up a large force of industrially and mechanically trained personnel. This meant shortages of skills, ingenuity and ability to improvise later on, when the economy was under the stresses and strains of large-scale warfare.

This economic potential could support a short war or a war of limited liabilities. The accumulated stocks of munitions, oil, planes and ships could be thrown into action and produce a devastating effect on unmobilized enemies. When this initial blow failed to result in peace, Japan, without significant help from Germany, was doomed. Its economy could not support a protracted campaign against an enemy even half as strong as the United States.

In addition, the success of the initial Japanese military operations delayed total economic mobilization until after the defeats of late 1942. Computed in constant prices, the gross national product rose from a level of 39.8 billion yen in the fiscal year beginning with April 1940, to only 41 billion yen in the fiscal year 1942. That this was due to an inadequate realization of requirements and inadequate planning, and not to the inherent limitations of the Japanese economy, is clear from the expansion that was secured after 1942. In the fiscal year 1943, the gross national product rose to 45.4 billion yen, and in 1944 to 50 billion yen.

The share of the gross national product devoted to direct war and munitions expenditures increased from 23 percent in 1941 to 31 percent in 1942, 42 percent in 1943 and 52 percent in 1944. In 1944, half of the remaining national product was accounted for by food. In 1943, however, the United States was devoting 45 percent of its vastly greater national product to direct war purposes. By the summer of 1944, the Japanese had exhausted the possibility of forcing a greater share of their economy into direct war activities. Their plants, railroad and mines were being, and had been for some time, under-maintained to a point where breakdowns were becoming more and more serious. The civilian population was underfed, was receiving practically no new clothing or miscellaneous civilian supplies, and was being worked to a degree of fatigue which was reflected in rising rates of absenteeism.

By 1944, Japan had increased ingot steel capacity to 225 percent of the 1937 capacity. A shortage of raw materials, however, which began with the United States embargo on scrap iron exports in July 1941 and was never overcome, prevented the operation of Japanese steel mills at anything approaching capacity. Japanese coal would not produce satisfactory metallurgical coke without the admixture of stronger continental coking coal; domestic iron ore was both limited in quantity and of lower grade than imported ores. The combination of limited quantities of high grade imported raw materials and lower grade domestic materials held production of ingot steel in the home islands to 6,800,000 tons in 1941, to a peak of 7,800,000 tons in 1943, and caused it to decline to 5,900,000 tons in 1944. This compared with a 1937 production of 5,800,000 tons and a theoretical capacity, using high-grade materials, of 13,600,000 tons in 1944. By the middle of 1i944, the increasing stringency of shipping and the interdiction of many of Japan's shipping routes had reduced coal and ore imports by two-thirds. Stockpiles of imported materials had already been heavily eaten into, and ingot steel production began to decline rapidly. In March 1945, imports of coal virtually ceased, and iron ore was cut off entirely, as the Japanese elected to devote their remaining shipping capacity to the hauling of vitally needed foodstuffs and salt. It is estimated by the Survey that, using only domestic raw materials, the Japanese steel industry could not have maintained a rate of production of ingot steel in excess of 1,500,000 tons per annum. By August 1945, the rate of output was still somewhat in excess of this

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figure, but would soon have been reduced. The decline in Japan's steel production can be attributed to its dependence on shipping and the destruction of that shipping. Had this industry not been mortally wounded by shipping attack and had its destruction by bombing been called for, the effectiveness of the few strategic bombing attacks directed against the steel industry indicates that destruction of the principal plants by bombing or paralysis of the industry by disruption of railroad transportation would have been possible, but only at a later date.

The steel shortage constituted an over-all limitation on the war potential of the Japanese economy. Japanese planners were, however, able to secure very substantial increases in the production of those military products which the experiences of the war had demonstrated to be of outstanding importance. Aircraft production of all types, including training planes, was stepped up from 700 planes per month in the summer of 1942 to 2,572 planes in September 1944. Aircraft engine production was not only increased correspondingly in numbers, but average horsepower was doubled. Aircraft and antiaircraft gun and ammunition production was expanded tenfold. Radar and communications equipment was stepped up fivefold. The most important consumer of steel was the shipbuilding industry. The increasingly critical nature of Japan's shipping situation caused her to expand her naval and merchant shipbuilding programs to a point where 35 percent of all steel consumed was being used in that industry alone. Construction of merchant ships increased from approximately 238,000 tons in 1941, to 1,600,000 tons of steel ships and 254,000 tons of wooden ships in 1944. During 1942, warship deliveries included one battleship of 64,000 tons and six small carriers totalling 84,000 tons. In 1944, no battleships, but four aircraft carriers of 114,500 displacement tons and 141,300 tons of escort vessels and submarines were delivered. The increases in production of high-priority items involved the scaling down of steel availability for lower priority items, such as tanks, larger caliber guns and trucks, and the almost complete elimination of steel for civilian requirements, construction, or export.

During 1944, the effects of the net loss of shipping and slow-down in ship operations became such that by the end of the year it no longer was possible to protect even high-priority war production by further shifting of allocations of scarce materials from items of lesser priority. In addition to steel, other basic elements of the economy were involved. Oil, although not as important as steel in its broad impact on the remainder of the economy, was of critical importance to Japan's military machine and to her merchant marine. Oil imports from the south began declining in August 1943, and had been eliminated by April 1945. Crude oil stocks were virtually exhausted; refinery operations had to be curtailed; and stocks of aviation gasoline fell to less than 1,500,000 barrels, a point so low as to require a drastic cut in the pilot-training program and even in combat air missions. Bauxite imports declined from 136,000 tons in the second quarter of 1944, to 30,000 tons in the third, and stockpiles were only 3,000 tons. Stockpiles and the time delay between the various stages of production cushioned for a time the inevitable effects of the blockade on finished munitions production, but by November 1944, the over-all level of Japanese war production had begun to turn down, including even the highest priority items, such as aircraft engines.

It is the opinion of the Survey that by August 1945, even without direct air attack on her cities and industries, the over-all level of Japanese war production would have declined below the peak levels of 1944 by 40 to 50 percent solely as a result of the interdiction of overseas imports.

By mid-1944 those Japanese in possession of the basic information saw with reasonable clarity the economic disaster which was inevitably descending on Japan. Furthermore, they were aware of the disastrous impact of long-range bombing on Germany, and, with the loss of the Marianas, could foresee a similar attack on Japan's industries and cities. Their influence, however, was not sufficient to overcome the influence of the Army which was confident of its ability to resist invasion.

THE AIR ATTACK AGAINST THE JAPANESE HOME ISLANDS

Basic United States strategy contemplated that the final decision in the Japanese war would be obtained by an invasion of the Japanese home islands. The long-range bombing offensive from the Marianas was initiated in November 1944, with that in mind as the primary objective. As in Europe prior to D-day, the principal measure of success set for strategic air action was the extent

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to which it would weaken enemy capability and will to resist our amphibious forces at the time of landings. This led, originally, to somewhat greater emphasis on the selection of targets such as aircraft factories, arsenals, electronics plants, oil refineries, and finished military goods, destruction of which could be expected to weaken the capabilities of the Japanese armed forces to resist at the Kyushu beachheads in November 1945, than on the disruption of the more basic elements of Japan's social, economic, and political fabric. Certain of the United States commanders and the representatives of the Survey who were called back from their investigations in Germany in early June 1945 for consultation stated their belief that, by the coordinated impact of blockade and direct air attack, Japan could be forced to surrender without invasion. The controlling opinion, however, was that any estimate of the effects of bombing on the Japanese social fabric and on the political decisions of those in control of Japan was bound to be so uncertain that target selection could safely be made only on the assumption that ground force invasion would be necessary to force capitulation.

With the benefit of hindsight, it appears that the twin objectives of surrender without invasion and reduction of Japan's capacity and will to resist an invasion, should the first not succeed, called for basically the same type of attack. Japan had been critically wounded by military defeats, destruction of the bulk of her merchant fleet, and almost complete blockade. The proper target, after an initial attack on aircraft engine plants, either to bring overwhelming pressure on her to surrender, or to reduce her capability of resisting invasion, was the basic economic and social fabric of the country. Disruption of her railroad and transportation system by daylight attacks, coupled with destruction of her cities by night and bad weather attacks, would have applied maximum pressure in support of either aim. This point of view was finally adopted. Although urban area attacks were initiated in force in March 1945, the railroad attack was just getting under way when the war ended.

The total tonnage of bombs dropped by Allied planes in the Pacific war was 656,400. Of this, 160,800 tons, or 24 percent, were dropped on the home islands of Japan. Navy aircraft accounted for 6,800 tons, Army aircraft other than B-29s for 7,000 tons, and the B-29s for 147,000 tons. By contrast, the total bomb tonnage in the European theater was 2,700,000 tons of which 1,360,000 tons were dropped within Germany's own borders.

Approximately 800 tons of bombs were dropped by China-based B-29s on Japanese home island targets from June 1944 to January 1945. These raids were of insufficient weight and accuracy to produce significant results.

By the end of November 1944, 4 months after seizure of the islands, the first of the long-range bomber bases in the Marianas became operational. The number of planes originally available was small and opposition was significant. Losses on combat missions averaged 3.6 percent. The tonnage dropped prior to 9 March 1945 aggregated only 7,180 tons although increasing month by month. The planes bombed from approximately 30,000 feet and the percentage of bombs dropped which hit the target areas averaged less than 10 percent. Nevertheless, the effects of even the relatively small tonnage hitting the selected targets were substantial. During this period, attacks were directed almost exclusively against aircraft, primarily aircraft engine, targets. The principal aircraft engine plants were hit sufficiently heavily and persistently to convince the Japanese that these plants would inevitably be totally destroyed. The Japanese were thereby forced into a wholesale and hasty dispersal program. The continuing pressure of immediate military requirements for more and more planes during the campaigns in the Pacific had prevented any earlier moves to disperse. When dispersal could no longer be avoided, the necessary underground tunnels, dispersed buildings, and accessory facilities such as roads, railroad spurs and power connections were not ready. As a result the decline in aircraft engine production, which shortages in special steels requiring cobalt, nickel and chrome had initiated in mid-1944, became precipitous.

On 9 March 1945, a basic revision in the method of B-29 attack was instituted. It was decided to bomb the four principal Japanese cities at night from altitudes averaging 7,000 feet. Japanese weakness in night fighters and antiaircraft made this program feasible. Incendiaries were used instead of high-explosive bombs and the lower altitude permitted a substantial increase in bomb load per plane. One thousand six hundred and sixty-seven tons of bombs were dropped on Tokyo in the first attack. The chosen areas were saturated. Fifteen square miles of Tokyo's most densely populated

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area were burned to the ground. The weight and intensity of this attack caught the Japanese by surprise. No subsequent urban area attack was equally destructive. Two days later, an attack of similar magnitude on Nagoya destroyed 2 square miles. In a period of 10 days starting 9 March, a total of 1,595 sorties delivered 9,373 tons of bombs against Tokyo, Nagoya, Osake, and Kobe destroying 31 square miles of those cities at a cost of 22 airplanes. The generally destructive effect of incendiary attacks against Japanese cities had been demonstrated.

Thereafter, urban area attacks alternated with visual and radar attacks against selected industrial or military targets. In April, an extensive program of sowing minefields in channels and harbors at night was added. In the aggregate, 104,000 tons of bombs were directed at 66 urban areas; 14,150 tons were directed at aircraft factories; 10,600 tons at oil refineries; 4,708 at arsenals; 3,500 tons at miscellaneous industrial targets; 8,115 tons at air fields and sea-plane bases in support of the Okinawa operation; and 12,034 mines were sown.

Bombing altitudes after 9 March 1945 were lower, in both day and night attacks. Japanese opposition was not effective even at the lower altitudes, and the percentage of losses to enemy action declined as the number of attacking planes increased. Bomb loads increased and operating losses declined in part due to less strain on engines at lower altitudes. Bombing accuracy increased substantially, and averaged 35 to 40 percent within 1,000 feet of the aiming point in daylight attacks from 20,000 feet or lower.

Monthly tonnage dropped increased from 13,800 tons in March to 42,700 tons in July, and, with the activation of the Eighth Air Force on Okinawa, would have continued to increase thereafter to a planned figure of 115,000 tons per month, had the war not come to an end.

Three-quarters of the 6,740 tons of bombs dropped by carrier planes on the Japanese home islands were directed against airfields, warships, and miscellaneous military targets, and one-quarter against merchant shipping and other economic targets. Most of the warships sunk in home ports had already been immobilized for lack of fuel. The accuracy of low-level carrier plane attack was high, being at least 50 percent hits within 250 feet of the aiming point. The attack against the Hakodate-Aomori rail ferries in July 1945 sank or damaged all twelve of the ferries, 17 steel ships, and 149 smaller ships.

ECONOMIC EFFECTS OF AIR ATTACK AGAINST THE JAPANESE HOME ISLANDS

The physical destruction resulting from the air attack on Japan approximates that suffered by Germany, even though the tonnage of bombs dropped was far smaller. The attack was more concentrated in time, and the target areas were smaller and more vulnerable. Not only were the Japanese defenses overwhelmed, but Japan's will and capacity for reconstruction, dispersal, and passive defense were less than Germany's. In the aggregate some 40 percent of the built-up area of the 66 cities attacked was destroyed. Approximately 30 percent of the entire urban population of Japan lost their homes and many of their possessions. The physical destruction of industrial plants subjected to high-explosive attacks was similarly impressive. The larger bomb loads of the B-29s permitted higher densities of bombs per acre in the plant area, and on the average somewhat heavier bombs were used. The destruction was generally more complete than in Germany. Plants specifically attacked with high explosive bombs were, however, limited in number.

The railroad system had not yet been subjected to substantial attack and remained in reasonably good operating condition at the time of surrender. Little damage was suffered which interfered with main line operations. Trains were running through Hiroshima 48 hours after the dropping of the atomic bomb on that city. Damage to local transport facilities, however, seriously disrupted the movement of supplies within and between cities, thereby hindering production, repair work and dispersal operations.

Japan's electric power system was properly rejected for specific attack because of the large number of small targets presented. Urban incendiary attacks destroyed the electric distribution systems in the burned-out areas simultaneously with the consumer load previously served by them. The hydro-electric generating plants and the transmission networks survived without substantial damage. Twenty-six urban steam-generating plants were damaged as an incident to other attacks, the aggregate loss of capacity being less than one-seventh of Japan's total generating capacity. The urban area incendiary attacks eliminated

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completely the residential and smaller commercial and industrial structures in the affected areas and a significant number of important plants, but a portion of the more substantially constructed office buildings and factories in those areas and the underground utilities survived. By 1944 the Japanese had almost eliminated home industry in their war economy. They still relied, however, on plants employing less than 250 workers for subcontracted parts and equipment. Many of these smaller plants were concentrated in Tokyo and accounted for 50 percent of the total industrial output of the city. Such plants suffered severe damage in urban incendiary attacks.

Four hundred and seventy thousand barrels of oil and oil products, 221,000 tons of foodstuffs and 2 billion square yards of textiles were destroyed by air attacks. Ninety-seven percent of Japan's stocks of guns, shells, explosives, and other military supplies were thoroughly protected in dispersed or underground storage depots, and were not vulnerable to air attack.

Physical damage to plant installations by either area or precision attacks, plus decreases due to dispersal forced by the threat of further physical damage, reduced physical productive capacity by roughly the following percentages of pre-attack plant capacity: oil refineries, 83 percent; aircraft engine plants, 75 percent; air-frame plants, 60 percent; electronics and communication equipment plants, 70 percent; army ordnance plants, 30 percent; naval ordnance plants, 28 percent; merchant and naval shipyards, 15 percent; light metals, 35 percent; ingot steel, 15 percent; chemicals, 10 percent.

The economic consequences of the physical damage wrought by air attack are closely interrelated with the concurrent effects of the interdiction of imports, the cumulative effects of under-maintenance of plants, and the declining health, vigor and determination of the Japanese people.

Let us first consider the level of Japanese industrial activity in July 1945, the last full month before surrender. Electric power and coal consumption were both almost exactly 50 percent of the peak reached in 1944. Production efficiency had, however, declined and the overall industrial output was approximately 40 percent of the 1944 peak. Output varied considerably as between industries, hit and unhit plants, and by areas. Output of air frame was 40 percent of the 1944 peak; aircraft engines, 25 percent; shipbuilding, 25 percent; army ordnance, 45 percent; and naval ordnance, 43 percent. Oil refining had declined to less than 15 percent of the 1943 output. Primary aluminum production was 9 percent of the 1944 peak. Although nitric acid production had declined to about 17 percent of the 1944 peak, explosives production was about 45 percent of the 1944 figure.

In each one of these industries, the occasion for the decline appears to have been different. Electric power consumption fell, not because more power was not available, but because demand had declined. Coal supply was primarily limited by the decline in inter-island shipping from Hokkaido and Kyushu, and the inability of the railroad system completely to fill the gap. Despite a decline in demand, shortages of coal were universal throughout the economy. Airframe production was limited primarily by the continuing effects of the dispersal program brought on by the initial bombing, and aggravated by the subsequent destruction of numerous plants prior to completion of dispersal. Had the level of production been any higher, however, aluminum stocks would have been exhausted and aluminum would have become the controlling bottleneck. In any event, not enough aircraft engines were being produced to equip the airframes. Aircraft engine production was plagued by shortages of special steels, but in July 1945, plant damage and delay in completing the underground and dispersed plants started in the spring of the year temporarily prevented the full use of the small stocks of such steels available at the time. Output of radar and radio equipment was limited by plant capacity, the small factories supplying parts having been destroyed in the Tokyo city raids and many of the larger plants either destroyed or forced to disperse. Shipbuilding and heavy ordnance production were limited by the availability of steel. Oil refineries, aluminum plants and steel plants were basically limited by lack of foreign raw materials. Explosive plants were still using up inventories of nitric acid but would shortly have had to adjust their output to the current availability of nitric acid.

The Japanese labor force had declined in efficiency due to malnutrition and fatigue, the destruction of much of the urban housing and the difficulties of local transportation. Production

hours lost through all causes including absenteeism, sickness, air-raid alerts and enforced idleness rose from 20 percent in 1944 to over 40 percent in July 1945. The size of the labor force employed did not materially decline and the productive hours actually worked remained sufficiently high to indicate that such influence as manpower deficiencies may have had on the over-all level of production in July 1945, was largely ascribable to the continued drafting of highly skilled workers into the armed services and to the inefficient administration of manpower in meeting the rapidly shifting requirements resulting from bombing, rather than to over-all lack of labor.

A Survey investigation of production in plants employing more than 50 employees in 39 representative cities of Japan indicates that production in those plants which suffered any direct physical damage dropped off by July 1945, to 27 percent of peak output in 1944, while production in the undamaged plants fell off to 54 percent. Production in all plants in the sample, including both hit and unhit, dropped to 35 percent of peak by July 1945. It appears probable that the indirect effects of the urban raids through increased absenteeism, disruption of supply lines and administrative confusion fully compensate for diversions of manpower and material from hit to unhit plants. The difference between 54 percent, being the rate of production in unhit plants, and 35 percent, being the average for all plants, is, therefore, a conservative indication of the impact of air attacks, both urban and precision, on production in these cities.

Even though the urban area attacks and attacks on specific industrial plants contributed a substantial percentage to the over-all decline in Japan's economy, in many segments of that economy their effects were duplicative. Most of the oil refineries were out of oil, the alumina plants out of bauxite, the steel mills lacking in ore and coke, and the munitions plants low in steel and aluminum. Japan's economy was in large measure being destroyed twice over, once by cutting off of imports, and secondly by air attack. A further tightening of Japan's shipping situation, so as to eliminate remaining imports from Korea and coastwise and inter-island shipping, coupled with an attack on Japan's extremely vulnerable railroad network, would have extended and cumulated the effects of the shipping attack already made.

Much of Japan's coastal and inter-island traffic had already been forced on to her inadequate railroads. The principal coal mines of Japan are located on Kyushu and Hokkaido. This coal traffic, formerly water borne, was moving by railroads employing the Kanmon tunnels and the Hakkodate-Aomori rail ferry. The railroads on Honshu include few main lines and these lines traverse bridges of considerable vulnerability. Japan is largely a mountainous country lacking automobile roads, trucks or the gasoline to make use of them. A successful attack on the Hakkodate rail ferry, the Kanmon tunnels and 19 bridges and vulnerable sections of line so selected as to set up five separate zones of complete interdiction would have virtually eliminated further coal movements, would have immobilized the remainder of the rail system through lack of coal, and would have completed the strangulation of Japan's economy. This strangulation would have more effectively and efficiently destroyed the economic structure of the country than individually destroying Japan's cities and factories. It would have reduced Japan to a series of isolated communities, incapable of any sustained industrial production, incapable of moving food from the agricultural areas to the cities, and incapable of rapid large-scale movements of troops and munitions.

The Survey believes that such an attack, had it been well-planned in advance, might have been initiated by carrier-based attacks on shipping and on the Hakkodate ferry in August 1944, could have been continued by aerial mining of inland waterways beginning in December 1944, and could have been further continued by initiating the railroad attack as early as April 1945. The Survey has estimated that force requirements to effect complete interdiction of the railroad system would have been 650 B-29 visual sorties carrying 5,200 tons of high explosive bombs. Monthly tonnages equal to one and one-half times that required to effect the original interdiction should have been sufficient, in view of the Japanese lack of preparation and slowness in effecting repairs, to maintain the interdiction by destroying such bridges and other facilities as the Japanese were able to repair. The use of Azon guided bombs, which could have been made available at that time, would have greatly increased accuracy against targets of this type and reduced force requirements to approximately one-sixth of those given above. An integrated

The economic effects of the transportation attack would have had a direct impact on the Japanese people and on their determination to continue the war. In order to bring maximum pressure on the civilian population and to complicate further the Japanese economic problems, night and bad weather attacks on urban areas could have been carried out simultaneously with the transportation attack. One of the important factors inducing Japan's leaders to accept unconditional surrender was a realization that the Japanese armed forces had lost their ability to protect the people and that under the impact of direct air attack and lowered livelihood their confidence in victory and determination to continue the war were rapidly declining.

THE HEALTH AND MORALE OF THE JAPANESE CIVILIAN POPULATION UNDER ASSAULT

Total civilian casualties in Japan, as a result of 9 months of air attack, including those from the atomic bombs, were approximately 806,000. Of these, approximately 330,000 were fatalities. These casualties probably exceeded Japan's combat casualties which the Japanese estimate as having totaled approximately 780,000 during the entire war. The principal cause of civilian death or injury was burns. Of the total casualties approximately 185,000 were suffered in the initial attack on Tokyo of 9 March 1945. Casualties in many extremely destructive attacks were comparatively low. Yokahoma, a city of 900,000 population, was 47 percent destroyed in a single attack lasting less than an hour. The fatalities suffered were less than 5,000.

The Japanese had constructed extensive firebreaks by tearing down all houses along selected streets or natural barriers. The total number of buildings torn down in this program, as reported by the Japanese, amounted to 615,000 as against 2,510,000 destroyed by the air attacks themselves. These firebreaks did not effectively stop the spread of fire, as incendiaries were dropped on both sides of the breaks. They did, however, constitute avenues of escape for the civilian population.

The Japanese instituted a civilian-defense organization prior to the war. It was not until the summer of 1944, however, that effective steps were taken to reduce the vulnerability of Japan's civilian population to air attacks. By that time, the shortage of steel, concrete and other construction materials was such that adequate air-raid shelters could no longer be built. Each family was given the obligation of providing itself with some kind of an excavation covered with bamboo and a little dirt. In addition, tunnels were dug into the sides of hills wherever the topography permitted.

Japanese planning and the means for carrying out the plans were thus deficient for a first-class civilian defense program. In spite of these limitations, such civilian defense measures as they were able to put through contributed substantially in minimizing casualties. School children and other nonessential urban dwellers were evacuated to the country. Those who remained were organized to combat fires and to provide mutual assistance. The air raid warning system was generally efficient. The weight of the individual attacks was, however, far heavier than the Japanese had envisaged or were able to cope with. In the major fire attacks, the civilian defense organizations were simply overwhelmed.

The growing food shortage was the principal factor affecting the health and vigor of the Japanese people. Prior to Pearl Harbor the average per capita caloric intake of the Japanese people was about 2,000 calories as against 3,400 in the United States. The acreage of arable land in Japan is only 3 percent of that of the United States to support a population over half as large. In order to provide the prewar diet, this arable acreage was more intensively cultivated, using more manpower and larger quantities of fertilizer than in any other country in the world; fishing was developed into a major industry; and rice, soybeans and other foodstuffs amounting to 19 percent of the caloric intake were imported. Despite the rationing of food beginning in April 1941 the food situation became critical. As the war progressed, imports became more and more difficult, the waters available to the fishing fleet and the ships and fuel oil for its use became increasingly restricted. Domestic food production itself was affected by the drafting of the younger males and by an increasing shortage of fertilizers.

By 1944, the average per capita caloric intake had declined to approximately 1,900 calories. By the summer of 1945 it was about 1,680 calories per

capita. Coal miners and heavy industrial workers received higher-than-average rations, the remaining populace, less. The average diet suffered even more drastically from reductions in fats, vitamins and minerals required for balance and adversely affected rates of recovery and mortality from disease and bomb injuries.

Undernourishment produced a major increase in the incidence of beriberi and tuberculosis. It also had an important effect on the efficiency and morale of the people, and contributed to absenteeism among workers.

Survey interrogation of a scientifically designed cross-section sample of the Japanese civilian population revealed a high degree of uniformity as between city and rural sectors of the population and as between various economic and social strata in their psychological reaction to the war. A uniformly high percentage considered Japan's greatest weaknesses to have been in the material realm, either lack of resources, productive plant or modern weapons, and her greatest strength to have been in the Yamato spirit of the Japanese people, their willingness to make every personal sacrifice, including that of life itself, for the Emperor or Japan.

The Japanese people reacted to news of the attack against the United States and its Allies with mingled feelings of fear, insecurity and hope. To a people wearied by 10 years of war in China, it was clear that this would be a major war and not an "incident". The early Japanese military successes, particularly the capture of Singapore and the southern regions, were followed by a wave of optimism and high confidence. Subsequent defeats were studiously withheld from the people or disguised as strategic withdrawals. Prior to the loss of Saipan confidence in eventual victory remained high in spite of exhausting work, poor nutrition and rising black market prices. In June 1944 approximately two percent of the population believed that Japan faced the probability of defeat. The fall of Saipan could not be kept from the Japanese people. Even though the psychological effect of this disaster was far greater on the Japanese leaders and intellectuals than on the mass of the population, all indices of Japanese morale began thereafter to decline. By December 1944 air attacks from the Marianas against the home islands had begun, defeats in the Philippines had been suffered, and the food situation had deteriorated; 10 percent of the people believed Japan could not achieve victory. By March 1945, when the night incendiary attacks began and the food ration was reduced, this percentage had risen to 19 percent. In June it was 46 percent, and just prior to surrender, 68 percent. Of those who had come to this belief over one-half attributed the principal cause to air attacks, other than the atomic bombing attacks, and one-third to military defeats.

Sixty-four percent of the population stated that they had reached a point prior to surrender where they felt personally unable to go on with the war. Of these, less than one-tenth attributed the cause to military defeats, one-quarter attributed the cause to shortages of food and civilian supplies, the largest part to air attack.

A striking aspect of the air attack was the pervasiveness with which its impact on morale blanketed Japan. Roughly one-quarter of all people in cities fled or were evacuated, and these evacuees, who themselves were of singularly low morale, helped spread dis