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The Pacific War was the part of World War II — and preceding conflicts — that took place in the Pacific Ocean, its islands, and in East Asia, between July 7, 1937, and August 14, 1945. The most decisive actions took place after the Empire of Japan attacked various countries, later known as the Allies (or Allied powers), on or after December 7, 1941, including an attack on United States forces at Pearl Harbor. Today, most Japanese also use the term "Pacific War" (太平洋戦争, Taiheiyō Sensō), while a few Japanese use the term "Greater East Asia War" (大東亜戦争, Dai Tō-A Sensō).
Participants
The Axis states which assisted Japan included the Japanese puppet states of Manchukuo and the Wang Jingwei Government (which controlled the coastal regions of China). Thailand joined the Axis powers under duress. Japan enlisted many soldiers from its colonies of Korea and Formosa (now called Taiwan). German and Italian naval forces operated in the Pacific and Indian Oceans. Conflict between China and JapanBackgroundThe roots of the war began in the late 19th century with China in political chaos and Japan rapidly modernizing. Over the course of the late 19th century and early 20th century, Japan intervened and finally annexed Korea and expanded its political and economic influence into China, particularly Manchuria. This expansion of power was aided by the fact that by the 1910s, China had fragmented into warlordism with only a weak and ineffective central government. However, the situation of a weak China unable to resist Japanese demands appeared to be changing toward the end of the 1920s. In 1927, Generalissimo Chiang Kai-shek and the National Revolutionary Army of the Kuomintang (KMT) led the Northern Expedition. Chiang was able to defeat the warlords in southern and central China, and was in the process of securing the nominal allegiance of the warlords in northern China. Fearing that Zhang Xueliang (the warlord controlling Manchuria) was about to declare his allegiance to Chiang, the Japanese staged the Mukden Incident in 1931 and set up the puppet state of Manchukuo. The nominal Emperor of this puppet state was better known as Henry Pu Yi of the defunct Qing Dynasty. Japan's imperialist goals in China were to maintain a secure supply of natural resources and to have puppet governments in China that would not act against Japanese interests. Although Japanese actions would not have seemed out of place among European colonial powers in the 19th century, by 1930, notions of Wilsonian self-determination meant that raw military force in support of colonialism was no longer seen as appropriate behavior by the international community. Hence Japanese actions in Manchuria were roundly criticized and led to Japan's withdrawal from the League of Nations. During the 1930s, China and Japan reached a stalemate with Chiang focusing his efforts at eliminating the Communists, whom he considered to be a more fundamental danger than the Japanese. The influence of Chinese nationalism on opinion both in the political elite and the general population rendered this strategy increasingly untenable. Though they had at first cooperated in the Northern Expedition, during the period of 1930–1934, the nationalist KMT and the Chinese Communist Party entered into direct conflict.[1] The Japanese capitalized on the infighting between Chinese factions to make greater inroads, forcing a landing at Shanghai in 1932.[2] Meanwhile, in Japan, a policy of assassination by secret societies and the effects of the Great Depression had caused the civilian government to lose control of the military. In addition, the military high command had limited control over the field armies who acted in their own interest, often in contradiction to the overall national interest. Pan-Asianism was also used as a justification for expansion. This is perhaps best summarized by the "Amo Doctrine" of 1934, issued by Eiji Amo, head of information department of the Japanese Foreign Ministry. Known as the "Monroe Doctrine of Asia," it announced Japan's intention for European countries to adopt a "hands off" policy in China, thereby negating the Open Door Policy. It stated that Japan was to be the sole leader in security in East Asia, including the task of defeating communism. Economic reason was also a very important factor leading to the invasion of China. During the Great Depression, Japanese exports to American and European markets were severely curtailed, and Japan turned to completely dominating China politically and ecnomically to provide a stable market. In the period leading up to full-scale war in 1937, Japan's use of force in localized conflicts to threaten China unless the latter reduced its protective tariff and suppressed anti-Japanese activities and boycotts were evidence to this. The Second Sino-Japanese WarIn 1936, Chiang was kidnapped by Zhang Xueliang (an event known as the Xian Incident). As a condition of his release, Chiang agreed to form a united front with the communists and fight the Japanese. Soon after, the Marco Polo Bridge Incident took place on July 7, 1937, which succeeded in provoking a war between the Republic of China and the Empire of Japan, the Second Sino-Japanese War. Though the Nationalist and Communist Chinese would cooperate in military campaigns against Japan and sought to create a united national front, Mao Zedong refused to directly submit to the Kuomintang, and maintained the aim of the Communists remained social revolution. In 1939, the Chinese Communist Red Army consisted of 500,000 troops independent of the KMT.[3] In 1939 Japanese forces tried to push into the Soviet Far East from Manchuria. They were soundly defeated in the Battle of Halhin Gol by a mixed Soviet and Mongolian force led by Georgy Zhukov. This stopped Japanese expansion to the North, and Japan and the Soviet Union kept an uneasy peace until 1945. In addition, throughout the 1930s Japan succeeded in alienating public opinion in the West, particularly the United States and Britain. During the early 1930s, public opinion in the United States had been neutral. However, news reports of the Panay incident caused American public opinion to swing against Japan. By 1941, Japan was in a stalemate in China. Although Japan had occupied much of north and central China, the Kuomintang had retreated to the interior setting up a provisional capital at Chongqing while the Chinese communists remained in control of base areas in Shaanxi. In addition, Japanese control of north and central China was somewhat tenuous, in that Japan was usually able to control railroads and the major cities ("points and lines"), but did not have a major military or administrative presence in the vast Chinese countryside. The Japanese found that its aggression against the retreating and regrouping Chinese army was stalled by the mountainous terrain in southwestern China while the Communists organized widespread guerrilla and saboteur activities in eastern and central China behind the Japanese front line. Japan sponsored several puppet governments, one of which was headed by Wang Jingwei. However, its policies of brutality toward the Chinese population, of not yielding any real power to the governments, and of support to several competing governments failed to make any of them a popular alternative to Chiang's government. Japan was also unwilling to negotiate directly with Chiang, nor was it willing to attempt to create splits in united front against it, by offering concessions that would make it a more attractive alternative than Chiang's government to the former warlords in Chiang's government. Although Japan was deeply mired in a quagmire, Japan's reaction to its situation was to turn to increasingly more brutal and depraved actions in the hope that sheer terror, including massive use of chemical and biological weapons against civilians and use of living civilians for medical and chemical experiments, would break the will of the Chinese population. War spreads in the EastThis, however, only had the effect of turning world public opinion against it. In an effort to discourage Japan's war efforts in China, the United States, Britain, and the Dutch government in exile (still in control of the oil-rich Dutch East Indies) stopped selling oil and steel to Japan. It was known as the "ABCD encirclement" (American-British-Chinese-Dutch) designed to deny Japan of the raw materials needed to continue its war in China. Japan saw this as an act of aggression, as without these resources Japan's military machine would grind to a halt. On December 8, 1941, Japanese forces attacked the British crown colony of Hong Kong, the International Settlement in Shanghai, and the Philippines, which was then a United States Commonwealth. Japan also used Vichy French bases in French Indochina to invade Thailand, then using the gained Thai territory to launch an assault against Malaya. Simultaneously (on December 7 in the Western Hemisphere), Japanese carrier-based planes launched a massive air attack on the American fleet at Pearl Harbor. More than 2,400 people were killed. Three battleships and two destroyers were sunk, among many other losses. Although Japan knew that it could not win a sustained and prolonged war against the United States,[citation needed] it was the Japanese hope that, faced with this sudden and massive defeat, the United States would agree to a negotiated settlement that would allow Japan to have free reign in China. This calculated gamble did not pay off; the United States refused to negotiate. Furthermore, the American losses were less serious than initially thought; the American carriers were out at sea while vital base facilities like the fuel oil storage tanks, whose destruction could have crippled the whole Pacific Fleet's operating capacity by itself, were left untouched. The United States enters the warImage:USSArizona PearlHarbor.jpg USS Arizona burned for two days after being hit by a Japanese bomb in the attack on Pearl Harbor. Until the attack on Pearl Harbor, the United States had remained out of the Asian and European conflict. The America First Committee, 800,000 members strong, had until that day vehemently opposed any American intervention in the foreign conflict, even as America provided military aid to Britain and Soviet Union through the Lend-Lease program. Opposition to war in the United States vanished after the attack. Four days after Pearl Harbor, on December 11, Nazi Germany declared war on the United States, drawing America into a two-theater war. In 1941, Japan had only a fraction of the manufacturing capacity of the United States, and was therefore perceived as a lesser threat than Germany. British, Indian and Dutch forces, already drained of personnel and matériel by two years of war with Nazi Germany, and heavily committed in the Middle East, North Africa and elsewhere, were unable to provide much more than token resistance to the battle-hardened Japanese. The Allies suffered many disastrous defeats in the first six months of the war. Two major British warships, HMS Repulse and HMS Prince of Wales were sunk by a Japanese air attack off Malaya on December 10, 1941. The government of Thailand surrendered within 24 hours of Japanese aggression and formally allied itself with Japan on December 21, allowing its military bases to be used as a launchpad against Singapore and Malaya. Hong Kong fell on December 25 and U.S. bases on Guam and Wake Island were lost at around the same time. Following the January 1, 1942 Declaration by the United Nations (not to be confused with the United Nations, organized after World War II), the Allied governments appointed the British General Sir Archibald Wavell as supreme commander of all "American-British-Dutch-Australian" (ABDA) forces in South East Asia. This gave Wavell nominal control of a huge but thinly-spread force covering an area from Burma to the Dutch East Indies and the Philippines. Other areas, including India, Australia and Hawaii remained under separate local commands. On January 15, Wavell moved to Bandung in Java to assume control of ABDA Command (ABDACOM). Japanese offensives, 1941-42January saw the invasions of Burma, the Dutch East Indies, New Guinea, the Solomon Islands and the capture of Manila, Kuala Lumpur and Rabaul. After being driven out of Malaya, Allied forces in Singapore attempted to resist the Japanese during the Battle of Singapore, but surrendered to the Japanese on February 15 1942; about 130,000[1] Indian, Australian and British troops along with Dutch sailors, became prisoners of war. The pace of conquest was rapid: Bali and Timor also fell in February. The rapid collapse of Allied resistance had left the "ABDA area" split in two. Wavell resigned from ABDACOM on February 25, handing control of the ABDA Area to local commanders and returning to the post of Commander-in-Chief, India. At the Battle of the Java Sea, in late February and early March, the Japanese Navy inflicted a resounding defeat on the main ABDA naval force, under Admiral Karel Doorman. Allied commanders in Java surrendered, but not before the Dutch KNIL forces inflicted heavy casualties on the Japanese attackers. Despite the hopelessness of their military situation and being outgunned on sea, in the air and on the ground, the Dutch forces, supported by many Indonesians, fought with extraordinary gallantry. More battles in Dutch East Indies area can be seen in the Netherlands East Indies campaign. The British, under intense pressure, made a fighting retreat from Rangoon to the Indo-Burmese border. This cut the Burma Road which was the western Allies' supply line to the Chinese National army commanded by Chiang Kai-shek. Cooperation between the Chinese Nationalists and the Communists had waned from its zenith at Battle of Wuhan, and the relationship between the two had gone sour as both attempted to expand their area of operations in occupied territories. Most of the Nationalist guerrilla areas were eventually overtaken by the Communists. On the other hand, some Nationalist units, along with collaborationists, were deployed for blockading the Communists rather than against the Japanese. Further, many of the forces of the Chinese Nationalists were warlords allied to Chiang Kai-Shek, but not directly under his command. "Of the 1,200,000 troops under Chiang's control, only 650,000 were directly controlled by his generals, and another 550,000 controlled by warlords who claimed loyalty to his government; the strongest force was the Szechuan army of 320,000 men. The defeat of this army would do much to end Chiang's power."[4] The Japanese used these divisions to press ahead in their offenses. Filipino and U.S. forces put up a fierce resistance in the Philippines until May 8 1942 when more than 80,000 of them surrendered. By this time, General Douglas MacArthur, who had been appointed Supreme Allied Commander South West Pacific, had relocated his headquarters to Australia. The U.S. Navy, under Admiral Chester Nimitz, had responsibility for the rest of the Pacific Ocean. Meanwhile, Japanese aircraft had all but eliminated Allied air power in South-East Asia and were making attacks on northern Australia, beginning with a disproportionately large and psychologically devastating attack on the city of Darwin on February 19, which killed at least 243 people. A raid by a powerful Imperial Japanese Navy aircraft carrier force into the Indian Ocean resulted in the Battle of Ceylon and sinking of the only British carrier, HMS Hermes in the theatre as well as 2 cruisers and other ships effectively driving the British fleet out of the Indian ocean and paving the way for Japanese conquest of Burma and a drive towards India. Air attacks on the U.S. mainland were insignificant, comprising of a submarine-based seaplane fire-bombing a forest in Oregon on September 9, 1942 (in 1944 fire balloon attacks were made using bombs carried to the states from the Japanese mainland by the jetstream). The Allies re-groupIn early 1942, the governments of smaller powers began to push for an inter-governmental Asia-Pacific war council, based in Washington D.C.. A council was established in London, with a subsidiary body in Washington. However the smaller powers continued to push for a U.S.-based body. The Pacific War Council was formed in Washington on April 1, 1942, with a membership consisting of President Franklin D. Roosevelt, his key advisor Harry Hopkins, and representatives from Britain, China, Australia, the Netherlands, New Zealand and Canada. Representatives from India and the Philippines were later added. The council never had any direct operational control and any decisions it made were referred to the U.S.-British Combined Chiefs of Staff, which was also in Washington. Allied resistance, at first symbolic, gradually began to stiffen. Australian and Dutch forces led civilians in a prolonged guerilla campaign in Portuguese Timor. The Doolittle Raid did minimal damage, but was a huge morale booster for the Allies, especially the United States, and caused repercussions throughout the Japanese military because they were sworn to protect the Japanese emperor and homeland, but did not intercept, down, or damage a single bomber[2]. Coral Sea and Midway: the turning pointImage:Uss lexington cv2 coral.jpg Lexington on fire at the Coral Sea. By mid-1942, the Japanese Combined Fleet found itself holding a vast area, even though it lacked the aircraft carriers, aircraft, and aircrew to defend it, and the freighters, tankers, and destroyers necessary to sustain it. Moreover, Fleet doctrine was incompetent to execute the proposed "barrier" defense.[5] Instead, they decided on additional attacks in both the south and central Pacific. While Yamamoto had used the element of surprise at Pearl Harbor, Allied codebreakers now turned the tables. They discovered an attack against Port Moresby, New Guinea was imminent with intent to invade and conquer all of New Guinea. If Port Moresby fell, it would give Japan control of the seas to the immediate north of Australia. Nimitz rushed the carrier USS Lexington to join USS Yorktown in a U.S.-Australian task force, under Admiral Frank Jack Fletcher to contest the Japanese advance. The result was the Battle of Coral Sea, the first naval battle in which the ships never sighted each other and aircraft were solely used to attack opposing forces. Although Lexington was sunk and Yorktown seriously damaged, the Japanese lost the aircraft carrier Shōhō, suffered extensive damage to Shōkaku, took heavy losses to the air wing of Zuikaku (both missed the operation against Midway the following month), and saw the Moresby invasion force turn back. Even though losses were almost even, the Japanese attack on Port Moresby was thwarted and their invasion forces turned back, yielding a strategic victory for the allies. Destruction of U.S. carriers was Yamamoto's main objective and he planned an operation to lure them to a decisive battle. After the Battle of Coral Sea, he had four frontline carriers operational — Sōryū, Kaga, Akagi and Hiryū — and believed Nimitz had a maximum of two: Enterprise and/or Hornet. Saratoga was out of action, undergoing repair after a torpedo attack, and Yorktown sailed after three days' work to repair her flight deck and make essential repairs, with civilian work crews still aboard. Yamamoto planned to lure Nimitz's carriers into battle, splitting his fleet and thereby gaining a further advantage. A large Japanese force was sent north to attack and invade the Aleutian Islands, off Alaska. The next stage of Yamamoto's plan called for the capture of Midway Atoll, after which it would be turned into a major Japanese airbase. This would give Yamamoto control of the central Pacific and/or a much better opportunity to destroy Nimitz's remaining carriers. However, in May Allied codebreakers discovered Midway was the true target. Nagumo was again in tactical command, but was focused on the invasion of Midway; Yamamoto's complex plan had no provision for intervention by Nimitz before the Japanese expected them.". Planned surveillance of the U.S. fleet by long range seaplane did not happen (as a result of an abortive identical operation in March) as planned so U.S. carriers were able to proceed to a flanking position on the approaching Japanese fleet without being detected. Nagumo had 272 planes operating from his four carriers, the U.S. 348 (of which 115 were land-based). Image:Hiryu f075712.jpg Hiryū under attack by B-17 Flying Fortress heavy bombers. As anticipated by U.S. commanders, the Japanese fleet arrived off Midway on June 4 and was spotted by PBY patrol aircraft[3]. By the time the Japanese had launched planes against the island, U.S. planes had scrambled and were heading for Nagumo's carriers. However, the initial U.S. attacks were poorly coordinated and arrived piecemeal. Land-based planes failed to score a single hit and half of them were lost. At 09:20 the first carrier aircraft arrived when Hornet's TBD Devastator torpedo bombers attacked; Zero fighters shot down all 15. At 09:35, 15 TBDs from Enterprise skimmed in over the water; 14 were shot down by Zeroes. The carrier aircraft had launched without coordinating their own dive bomber and fighter escort coverage so the torpedo bombers had arrived first thereby distracted the attention of the Nagumo's Zero fighters. When the last of the U.S. Navy strike aircraft arrived, the Zeros could not protect his ships against a high-level dive bomber attack. In addition, his four carriers had drifted out of formation, reducing the concentration of their anti-aircraft fire. In his most-criticized error, although Nagumo ordered aircraft armed for shipping attack as a hedge against discovery of U.S. carriers, he changed arming orders twice, based on reports an additional strike was needed against Midway and the sighting of the American task force, wasting time and leaving his hangar decks crowded with refueling and rearming strike aircraft and ordnance stowed outside the magazines. Yamamoto's dispositions, which left Nagumo with inadequate reconnaissance to detect Fletcher before he launched, are often ignored.[6] When SBD Dauntless dive bombers from Enterprise and Yorktown appeared at an altitude of 10,000 feet, the Zeroes at sea level were unable to respond before the bombers tipped over in their dives. The U.S. bombers scored significant hits; Sōryū, Kaga, and Akagi all caught fire. Hiryū survived this wave of attacks and launched an attack against the American carriers which caused severe damage to Yorktown (which was later finished off by a Japanese submarine). A second attack from the U.S. carriers a few hours later found Hiryū and finished her off. Yamamoto had four reserve carriers with his separate surface forces, all too slow to keep up with the Combined Fleet and therefore never in action. Yamamoto's enormous superiority in terms of naval artillery was irrelevant because the U.S. now had air superiority in the Midway area and could refuse a surface gunfight. Midway was a decisive victory for the U.S. Navy and the high point in Japanese strategic aspirations in the Pacific. New Guinea and the SolomonsJapanese land forces continued to advance in the Solomon Islands and New Guinea. From July, 1942, a few Australian Militia (reserve) battalions, many of them very young and untrained, fought a stubborn rearguard action in New Guinea, against a Japanese advance along the Kokoda Track, towards Port Moresby, over the rugged Owen Stanley Ranges. The Militia, worn out and severely depleted by casualties, were relieved in late August by regular troops from the Second Australian Imperial Force, returning from action in the Middle East. Image:PacificTheaterAug1942.jpg The Pacific Theater in August, 1942. In early September 1942, Japanese Special Naval Landing Forces (commonly, but erroneously, called "Japanese marines") attacked a strategic Royal Australian Air Force base at Milne Bay, near the eastern tip of New Guinea. They were beaten back by the Australian Army and some U.S. forces, inflicting the first outright defeat on Japanese land forces since 1939. GuadalcanalAt the same time as major battles raged in New Guinea, Allied forces spotted a Japanese airfield under construction at Guadacanal. The Allies made an amphibious landing in August to convert it to their use and start to reverse the tide of Japanese conquests. As a result, Japanese and Allied forces both occupied various parts of Guadalcanal. Over the following six months, both sides fed resources into an escalating battle of attrition on the island, at sea, and in the sky, with eventual victory going to the Allies in February 1943. It was a campaign the Japanese could ill afford. A majority of Japanese aircraft from the entire South Pacific area was drained into the Japanese defense of Guadalcanal. The U.S. Air Forces based at Henderson Field became known as the Cactus Air Force (from the codename for the island), and held their own. The Japanese launched a pair of ill-coordinated attacks on U.S. positions around Henderson Field to suffer bloody repulse and then to suffer even worse losses to starvation and disease during the retreat. These offensives were suppiled by a series of ill-considered supply runs (called the "Toyoko Express" by the Americans), often also bringing about night battles with the U.S. Navy, expending destroyers IJN could not spare. Japanese troops named Guadacanal "The Island of Death" as their fortunes declined. The Japanese survivors were evacuated in another series of "Toyoko Express" runs. The final American assaults found empty camps. Allied advances in New Guinea and the SolomonsBy late 1942, the Japanese were also retreating along the Kokoda Track in the highlands of New Guinea. Australian and U.S. counteroffensives culminated in the capture of the key Japanese beachhead in eastern New Guinea, the Buna-Gona area, in early 1943. In June 1943, the Allies launched Operation Cartwheel, which defined their offensive strategy in the South Pacific. The operation was aimed at isolating the major Japanese forward base, at Rabaul, and cutting its supply and communication lines. This prepared the way for Nimitz's island-hopping campaign towards Japan. Stalemate in China and South-East AsiaBritish Commonwealth forces were also counter-attacking in Burma, albeit with limited success. In August 1943, the western Allies formed a new South East Asia Command (SEAC) to take over strategic responsibilities for Burma and India from the British India Command, under Wavell. In October 1943, Churchill appointed Admiral Lord Louis Mountbatten as Supreme Allied Commander, SEAC. General William Slim was commander of Commonwealth land forces and directed the Burma Campaign. General Joseph Stilwell commanded U.S. forces in the CBI Theater, directed aid to China and assisted in the coordination of Chinese operations. On November 22, 1943 U.S. President Franklin D. Roosevelt, British Prime Minister Winston Churchill, and ROC leader Chiang Kai-Shek met in Cairo, Egypt, to discuss a strategy to defeat Japan. The meeting was also known as Cairo Conference and concluded with the Cairo Declaration. Allied offensives, 1943-44Image:Cairo conference.jpg The Allied leaders of the Asian and Pacific Theaters: Generalissimo Chiang Kai-shek, Franklin D. Roosevelt, and Winston Churchill meeting at the Cairo Conference in 1943. Midway proved to be the last great naval battle for two years. U.S. Admiral Ernest J. King complained that the Pacific deserved 30% of Allied resources but was getting only 15%; he used what he had to neutralize the Japanese forward bases at Rabaul and Truk. The United States used the two years to turn its vast industrial potential into actual ships and planes and trained pilots. At the same time, Japan, lacking both an industrial base and a technological strategy, and lacking a good pilot training program, fell further and further behind. In strategic terms the Allies began a long movement across the Pacific, seizing one island base after another. Not every Japanese stronghold had to be captured; some, like Truk, Rabaul and Formosa were neutralized by air attack and bypassed. The goal was to get close to Japan itself, then launch massive strategic air attacks and finally an invasion. In November 1943, U.S. Marines sustained high casualties when they overwhelmed the 4,500-strong garrison at Tarawa. This helped the allies to improve the technique of amphibious landings, learning from their mistakes and implementing changes such as thorough pre-emptive bombings and bombardment, more careful planning regarding tides and landing craft schedules, and better overall coordination. The U.S. Navy did not seek out the Japanese fleet for a decisive battle, as Mahanian doctrine would suggest; the Allied advance could only be stopped by a Japanese naval attack. The submarine war in the PacificU.S., British, and Dutch submarines, operating from bases in Australia, Hawaii and Ceylon, played a major role in defeating Japan. This was the case even though submarines made up a small proportion of the Allied navies—less than two percent in the case of the U.S. Navy.[7] Submarines strangled Japan by sinking its merchant fleet, intercepting many troop transports, and cutting off nearly all the oil imports that were essential to warfare. By early 1945 the oil tanks were dry.[8] U.S. submarines alone accounted for 56% of the Japanese merchantmen sunk; most of the rest were hit by planes at the end of the war, or were destroyed by mines. U.S. submariners also claimed 28% of Japanese warships destroyed.[9] Furthermore they played important reconnaissance roles, as at the battles of the Philippine Sea and Leyte Gulf, when they gave accurate and timely warning of the approach of the Japanese fleet. Submarines operated from secure bases in Fremantle, Australia; Pearl Harbor; Trincomalee, Ceylon; and later Guam. These had to be protected by surface fleets and aircraft. The submarines did not adopt a defensive posture and wait for the enemy to attack. Within hours of Pearl Harbor, Roosevelt ordered a new doctrine into effect: unrestricted submarine warfare against Japan. This meant sinking any warship, commercial vessel, or passenger ship in Axis controlled waters, without warning and without help to survivors.[10] Image:I-400.jpg The Japanese submarine I-400. The Sen Toku I-400 class were the largest non-nuclear submarines ever constructed. Japanese submarines were not used to their full potential during the Pacific War. While Japan had some of the best-quality submarines of World War II, including many with ranges exceeding 16,000 kilometres (10,000 miles), these did not have a significant impact. In 1942, the Japanese fleet subs performed well, knocking out or damaging many Allied warships. However, Imperial Japanese Navy (and prewar U.S.) doctrine stipulated naval campaigns are won only by fleet battles, not commerce raiding. So, while the U.S. had an unusually long supply line between its west coast and frontline areas that was vulnerable to submarine attack, Japan's submarines were instead used for long range reconnaissance and to resupply strongholds which had been cut off, such as Truk and Rabaul. In addition, Japan honored its neutrality treaty with the Soviet Union, and ignored U.S. freighters shipping millions of tons of war supplies from San Francisco to Vladivostok.[11] The U.S. Navy, by contrast, relied on commerce raiding from the outset. In addition, however, the problems of MacArthur's forces trapped in the Philippines led to diversion of boats to "guerrilla submarine" missions. As well, basing in Australia placed boats under Japanese aerial threat while en route to patrol areas, inhibiting effectiveness, and Nimitz relied on submarines for close surveillance of enemy bases. Furthermore, the standard issue Mark XIV torpedo and its Mark VI exploder were both defective, problems not corrected until September 1943. Worst of all, before the war, an uninformed Customs officer had seized a copy of the Japanese merchant marine code (called the "maru code" in the USN), not knowing Office of Naval Intelligence had broken it;[12] Japan promptly changed it, and it was not recovered until 1943. Thus it was not until 1944 the U.S. Navy learned to use its 150 submarines to maximum effect: effective shipboard radar installed, commanders seen to be lacking in aggression replaced, and faults in torpedoes fixed. Fortunately, Japanese commerce protection was "shiftless"[13] and convoys were poorly organized and defended compared to Allied ones, a product of flawed IJN doctrine and training, errors concealed by American faults as much as Japanese overconfidence. The number of U.S. submarines on patrol at any one time increased from 13 in 1942, to 18 in 1943, to 43 in late 1944. Half of their kills came in 1944, when over 200 subs were operating.[9] By 1945, patrols had decreased because so few targets dared to move on the high seas. In all, Allied submarines destroyed 1,200 merchant ships. Most were small cargo carriers, but 124 were tankers bringing desperately needed oil from the East Indies. Another 320 were passenger ships and troop transports. At critical stages of the Guadalcanal, Saipan, and Leyte campaigns, thousands of Japanese troops were killed before they could be landed. Over 200 warships were sunk, ranging from many auxiliaries and destroyers to eight carriers and one battleship. Underwater warfare was especially dangerous; of the 16,000 Americans who went out on patrol, 3,500 (22%) never returned, the highest casualty rate of any American force in World War II. For every 27 enemy ships that went down, one American sub and 67 sailors were lost.[14] Japanese counteroffensives in China, 1944In mid-1944, Japan launched a masssive | |||||||||||
