Pacific Theater aircraft carrier operations during World War II

Naval historians such as Evan Mawdsley, Richard Overy, and Craig Symonds concluded that World War II's decisive victories on land could not have been won without decisive victories at sea.Overy, p. 61Symonds, p. 641 Naval battles to keep shipping lanes open for combatant's movement of troops, guns, ammunition, tanks, warships, aircraft, raw materials, and food largely determined the outcome of land battles. Without the Allied victory in keeping shipping lanes open during the Battle of the Atlantic, Britain could not have fed her people or withstood Axis offensives in Europe and North Africa. Without Britain's survival and without Allied shipments of food and industrial equipment to the Soviet Union, her military and economic power would likely not have rebounded in time for Soviet soldiers to prevail at Stalingrad and Kursk.Overy pp. 19, 254, 321Mawdsley, p. 478

Without victories at sea in the Pacific Theater, the Allies could not have mounted amphibious assaults on or maintained land forces on Guadalcanal, New Guinea, Saipan, The Philippines, Iwo Jima, or Okinawa. Allied operations in the Atlantic and Pacific war theaters were interconnected because they frequently competed for scarce naval resources for everything from aircraft carriers to transports and landing craft.Symonds, WWII at Sea, pp. xi-xii Effective transport of troops and military supplies between the two war theaters required naval protection for shipping routes around the Cape of Good Hope, through the Suez canal, and through the Panama Canal. In both theaters, maritime dominance enabled combatants to use the sea for their own purposes and deprive its use by adversaries. As naval historian Admiral Herbert Richmond stated, "Sea power did not win the war itself: it enabled the war to be won".Mawdsley, pp. xxxix, 477

Aircraft carriers played a major role in winning decisive naval battles,Symonds, p. 268 supporting key amphibious landings, and keeping critical merchant shipping lanes open for transporting military personnel and their equipment to land battle zones. This article is part of a series that covers World War II from the vantage point of aircraft carrier operations and is focused upon operations in the Pacific Theater.

Pacific War overview (1930–1945) Japan embarked on imperialistic initiatives in the 1930s which started with the Japanese invasion of Manchuria in 1931 leading to the Second Sino-Japanese War in 1937 and invading French Indochina in 1940. From 1938, the US imposed increasingly restrictive trade restrictions on Japan of oil and other critical materials. The Japanese harbored grievances over perceived humiliations by the West in the past.Parshall and Tully, p. 75Pike, pp. 10-15, 23-25 Rather than withdraw from her conquests as demanded, she chose to acquire access to oil by further conquest, knowing that this would involve war with America, British Empire and others. Japan's view was that, if Germany prevailed in Europe, Japan's only serious enemy would be America, where public opinion was decidedly against war.Dull, p. 6 Japan's confidence was buoyed by her perception that she had never lost a war.Dull, p. 3

Japanese strategy Mindful of the huge wartime industrial potential of America, yet hopeful that Axis successes in Europe would limit what the Allies could undertake in the Pacific,Dull, p. 7 the Imperial Japanese Navy (IJN) pursued a strate strategy of Kantai Kessen - winning a decisive battle at the beginning of a short war, after which she could dictate peace terms.Dull, pp. 6-8

Pearl Harbor On December 7, 1941, Japan launched a series of nearly simultaneous land and sea assaults. One of these temporarily crippled the American navy by destroying its battleship fleet at Pearl Harbor.Dull, p. 1 Over the next four months, Japan's army and navy drove the Americans out of the Philippines and neutralized potential American stepping stones back to the Philippines by overrunning Wake Island and Guam.

Japan invaded Malaya (sinking two British Royal Navy capital ships in the process) and Borneo, Singapore, and neutralized the British position in Easter Sunday Raid on Ceylon. Dutch possessions in the East Indies were also overrun, giving Japan access to vast quantities of oil. Australia was driven out of New Britain and parts of New Guinea. Japan then established a defensive perimeter around her expanded empire by fortifying bases at many of the newly conquered possessions.

Indian Ocean Emboldened by her relatively easy victories, Japan then sought to move her defensive perimeter even further outward. She raided the Indian Ocean. The British withdrew part of the Eastern Fleet to Africa's east coast. She attempted to isolate Australia and New Zealand from America by conquering the rest of New Guinea with an eye then to occupying New Caledonia, Fiji, and Samoa. This initiative was rebuffed at the Battle of the Coral Sea. The following month, at the Battle of Midway Japan lost four of the six fleet carriers that had been instrumental in her earlier successes. It was a decisive battle from which Japan would not recover.

Allied strategy With Japan's offensive capabilities blunted, the Allies took the strategic initiative. After six months of bitter fighting on land, sea, and in the air, the Allies established and held a position on Guadalcanal. The Allies then pursued a three pronged drive toward Japan.

Philippines The first, under General Douglas MacArthur, attacked up the northern coast of New Guinea. Simultaneously, Admiral William Halsey Jr., island hopped up the Solomon Islands and Admiralty Islands and merged with Gen. MacArthur's campaign for the assault on the Philippines.

Central Pacific The second prong, under Admiral Chester Nimitz, island-hopped across the Central Pacific taking the Gilbert and Marshall Islands to the Marianas. Nimitz then supported MacArthur's invasion of the Philippines. The Allies successfully employed a strategy of by-passing Japanese strongpoints, isolating them by establishing air superiority, and then letting them wither on the vine. Japanese bases, instead of being valuable defensive positions, became liabilities that had to be supplied using scarce IJN resources. At the same time the American submarine force was destroying the majority of the Japanese merchant fleet.

China The third prong was an anticipated thrust from India and Burma through China. Japanese conquests during the 1930s had left China's army exhausted, and logistical support for her from India and Burma was limited. Chinese military activity kept some 600,000 Japanese troops tied down (15% of IJA's troops in 1943–44) that might otherwise have resisted the other Allied thrusts. Nonetheless, the assault on Japan through the China route never became viable.

Japanese home islands After the other two thrusts met up in the Philippines, the Allies invaded Iwo Jima and Okinawa and prepared for a final and costly assault on the Japanese home islands. This became unnecessary when the destruction resulting from the atomic bombings of Hiroshima and Nagasaki followed by Soviet entry into the war against Japan brought about Japan's surrender.

Carriers in the Pacific theater (1939–1945)

Wartime carrier operations in the Pacific began with Japan using carriers to provide combat support for her invasions of China. Japan innovated the coordinated, massed use of aircraft from multiple carriers to establish air superiority wherever they struck.Tully, Kidō Butai She launched her war with America by a raid on Pearl Harbor with 412 aircraft from six fleet carriers.Parshall and Tully, p. 90 It was entirely a carrier-launched aircraft operation. Opposing surface warships did not see or fire upon one another.

Deployment of carriers in 1942 For five months, Japan's powerful carrier fleet, the Kidō Butai, dominated the Western Pacific and Eastern Indian Oceans. Japan attacked with near impunity wherever she chose. This dominance ended abruptly in May 1942 when Allied naval forces, centered around aircraft carriers, frustrated Japanese amphibious invasion plans for Port Moresby, New Guinea during the Battle of the Coral Sea. The Allies sank a light carrier but lost a fleet carrier in return. Each side also sustained heavy damage to another fleet carrier. The following month, the Allies sank four of Japan's six fleet carriers during the Battle of Midway at the cost of one American carrier. Two months after that, with air cover from American carriers, the Allies established a tenuous toehold on Guadalcanal at the southern end of the Solomon Islands. Both sides committed major troops and naval resources in their efforts to gain control of the island that neither side really wanted but could not afford to leave to the enemy.Morison, p. 177 Opposing carriers fought major naval engagements over Guadalcanal, including carrier battles in the Eastern Solomon Islands and the Santa Cruz Islands. Overall combined losses for both sides during the Guadalcanal Campaign were 26,000 dead, three aircraft carriers sunk, four carriers heavily damaged, 67 other warships sunk, and 1,300 aircraft lost. As a result of these engagements, there were no operational Allied fleet or light carriers in the Pacific for a two-week period at the end of October 1942. Two such Japanese carriers were then operational but not engaged, in part because of the excessive loss of experienced pilots and supporting aircrews. Nonetheless, the Allies held Guadalcanal and the tide in the Pacific had decisively turned. For the rest of the war in the Pacific, the Allies maintained the strategic initiative.

The table below shows the raids and battles at which Japan's carriers were engaged during the year following the attack on Pearl Harbor. Some carriers were out of action during this period due to damage or to lacking sufficient aircraft and/or pilots to sortie with the fleet.

Legend indicates sunk during or shortly after battle indicates month the carrier was newly commissioned + Imperial Japanese Navy Carriers, Pacific Theater (Dec 1941 – Dec 1942) Name Dec 41 Jan 42 Feb 42 Mar 42 Apr 42 May 42 Jun 42 Jul 42 Aug 42 Sep 42 Oct 42 Nov 42 Dec 42Fleet:1Akagi CV Pearl HarborRabaulDarwinJavaCeylon Midway⇘2Kaga CV Pearl HarborRabaulDarwinJavarepairs Midway⇘3Sōryū CV Pearl, WakeAmbonDarwinJavaCeylon Midway⇘4Hiryū CV Pearl, Wake AmbonDarwinJavaCeylon Midway⇘5Shōkaku CV Pearl HarborRabaul CeylonCoral Searepairs Eastern Solomons Santa Cruzrepairsrepairs6Zuikaku CV Pearl HarborRabaul CeylonCoral Sealow on aircrews KiskaEastern Solomons Santa Cruzlow on aircrews low on aircrews7Jun'yō CV CDutch HarborKiska Santa Cruz 8Hiyō CV C Guadalcanal Light:1Hōshō CVL Pearl Harbor (distant cover) Midway (distant) 2Ryūjō CVL PhilippinesMalayJavaJavaBengal Dutch HarborKiskaEastern Solomons⇘3Zuihō CVL Philippines Midway (distant)Kiska Santa Cruz 4Shōhō CVL C Coral Sea⇘5Ryūhō CVL CEscort:1Taiyō CVE Philippines TrukTruk 2Un'yō CVE C 3Chūyō CVE C Principal Sources: Pike, Y'Blood.

The table below shows the location of American carriers at the time of the Japanese raid on Pearl Harbor. Also shown are raids and battles in which American carriers were engaged during the first year of the war. Legend indicates sunk during or shortly after battle indicates month the carrier was newly commissioned