Pacific Campaigns of 1941–45

military actions between the armed forces of Japan and those of the USA and its allies during World War II (1939–45) in the Pacific Ocean, as well as in Indochina, Burma, and China. There were three major campaigns: 1941–42,1942–43, and 1944–45.

In 1941, Japan, taking advantage of the strained international situation brought about by fascist Germany’s attack on the USSR, decided to employ armed force in order to resolve its conflicts with the USA and Great Britain and to attain a dominant position in the Pacific area. While continuing military actions in China, begun in 1937, Japan set as its principal goal in the war against the USA and Great Britain the capture of Burma, Malaya, Indonesia, and the Philippines. This expansion would give Japan access to India and the Indian Ocean and would make available large supplies of strategic raw materials (rubber, petroleum, iron) and foodstuffs; it would also deprive China of communications with the countries of Southeast Asia. In order to secure Japan’s rearline areas from the east and to support operations in the South Seas, plans were made to destroy the principal naval forces of the USA in the Pacific Ocean, to capture the bases on Wake Island and Guam, and to occupy the Bismarck Archipelago. All of this was meant to compel the USA to discontinue the war.

By December 1941, the armed forces of Japan amounted to 2.4 million men, 51 divisions and 58 brigades, ten battleships, ten aircraft carriers with 575 airplanes, 38 cruisers (including one in dry dock for major repairs), 112 destroyers, 65 submarines, and 3,175 aircraft (air-based and army air force). In Manchuria the Kwantung Army had been deployed under the command of General Y. Umezu (replaced by General O. Yamada in March 1945), comprising 13 divisions, 24 brigades, and 560 aircraft. Operating in China was the Expeditionary Army of General S. Hata (replaced by General Y. Okamura in December 1944), consisting of 21 divisions, 20 brigades, 160 aircraft, one cruiser, and three destroyers. There were two divisions stationed in Korea, while the homeland itself had four divisions, 11 brigades, about 100 army airplanes, six battleships, three aircraft carriers, four cruisers, 11 destroyers, and ten submarines.

To fight against the USA and Great Britain, Japan set aside 11 divisions, three brigades (220,000 to 230,000 men), more than 1,700 army and navy aircraft, four battleships, seven aircraft carriers, 32 cruisers, 79 destroyers, and 55 submarines. The combined fleet was initially commanded by Admiral I. Yamamoto, until Apr. 18,1943, then by Admiral M. Koga, and beginning in May 1944 by Admiral S. Toyoda.

The Allied armed forces in the Pacific Theater consisted of 22 divisions (more than 370,000 men), more than 1,350 aircraft, ten battleships, one battle cruiser, three aircraft carriers with 220 airplanes, 35 cruisers, 100 destroyers, and 69 submarines. The US Pacific Fleet (nine battleships, three aircraft carriers, 21 cruisers, 67 destroyers, 27 submarines, and 390 airplanes) had its main forces based in the Hawaiian Islands. Three divisions of Marines and reserve forces were stationed in the Hawaiian and Samoan Islands. The Philippines was headquarters for three American divisions and four Filipino divisions in the process of being formed, along with 277 aircraft, as well as for the US Asiatic Fleet (three cruisers, 13 destroyers, and 29 submarines). Two British divisions and 85 aircraft were stationed in Burma, and three British divisions and 247 aircraft were deployed in Malaya and Singapore. Two Dutch divisions, 200 aircraft, three cruisers, seven destroyers, and 13 submarines were based in Indonesia, and five Australian divisions and 165 aircraft were spread over New Guinea, the Bismarck Archipelago, the Solomons, and Australia. The British Eastern Fleet had one battleship, one battle cruiser, eight cruisers, and 13 destroyers.

Campaign of 1941–42. The campaign of 1941–12 began on December 7 (December 8 Tokyo time), 1941, with surprise attacks by Japanese aircraft against the US Pacific Fleet at Pearl Harbor and American military facilities in the Philippines and with invasions by Japanese troops in Thailand and Malaya. As a result, the US Pacific Fleet suffered great losses and was put out of commission. This shifted the balance of naval forces sharply in favor of Japan. On December 8, the Japanese Twenty-third Army launched an offensive from the Chinese coast against the British base of Hong Kong, which was captured on December 25. In order to proceed with operations in the western Pacific and in the South Seas, the Southern Group of armies was created under the command of General H. Terauchi (consisting of the Japanese Fourteenth, Fifteenth, Sixteenth, and Twenty-fifth armies, to which the Seventeenth and Eighteenth armies were subsequently added). The group had approximately 580 aircraft.

On Dec. 8,1941, the Japanese Fifteenth Army, which was concentrated in Indochina (occupied by Japanese troops in July 1941 according to an agreement with the Vichy government), crossed the border of Thailand. On December 21, the Thai government concluded an alliance with Japan and in January 1942 declared war on the USA and Great Britain. From Dec. 8, 1941, to Feb. 15, 1942, the Japanese Twenty-fifth Army, acting in concert with the Malayan task force of the Japanese fleet, carried out the Malayan (Singapore) Operation. On December 10, Japanese aircraft sank a British battleship and a battle cruiser, which ensured the Japanese fleet of dominance in the western Pacific. The Twenty-fifth Army, having landed on the eastern coast of the Malay Peninsula, occupied it by the end of January 1942 and on February 8–9 began an offensive against Singapore. On February 15, the blockaded, 70,000-man garrison of Singapore surrendered. Acting in concert with the Philippine task force of the Japanese fleet, the Japanese Twenty-fourth Army carried out the Philippine Operation (from Dec. 8, 1941, to May 6, 1942). After almost all American aircraft had been put out of commission by air strikes, the Fourteenth Army landed on the island of Luzon in December and captured Manila on January 2. On May 6, 1942, the American and Filipino troops, who were blockaded on the Bataan Peninsula and the fortress of Corregidor, surrendered.

During the course of the Burma Operation (Jan. 20-May 20, 1942), Japanese troops took Rangoon on March 8 and then drove Anglo-Indian and Chinese troops back across the Burmese-Indian and Burmese-Chinese borders. The Java Operation (Feb. 18-Mar. 10, 1942) was conducted by the Japanese Sixteenth Army, acting in concert with large naval forces. From December 1941 to February 1942 the Japanese captured the islands of Borneo (Kalimantan), Celebes (Sulawesi), Bali, and Sumatra, having smashed the weak resistance put up by Dutch troops. On February 27–28, an Anglo-Dutch fleet lost five cruisers and six destroyers in the Java Sea. On March 1, Japanese troops landed on the island of Java and by March 10 had captured it. The occupation of the Dutch East Indies gave Japan enormous reserves of strategic raw materials.

In January 1942 the Japanese armed forces captured western and central New Guinea, New Britain, the Gilbert Islands, and most of the Solomon Islands.

On May 4, 1942, a large Japanese naval landing force under the protective cover of three aircraft carriers, 11 cruisers, 13 destroyers, and six submarines moved out of Rabaul with the aim of capturing southeastern New Guinea and Port Moresby. In the naval battle of the Coral Sea (May 7–8), American carrier-based aircraft sank one aircraft carrier and one cruiser and compelled the Japanese landing force to pull back. The Japanese command decided to shift their efforts to the central and northern Pacific and to capture US bases on Midway Island and the Aleutian Islands. On June 6–7, Japanese troops occupied the islands of Attu and Kiska in the Aleutians, but they did not succeed in capturing Midway Island. The American command, having discovered the enemy’s intentions, assembled considerable forces, and in the battle of Midway (June 4–5, 1942) they smashed the Japanese striking force, which lost four aircraft carriers.

The enormous losses suffered by the Japanese Navy during the period 1941–12 (two battleships, six aircraft carriers, five cruisers, 21 destroyers, and 18 submarines) resulted in Japan’s loss of its supremacy at sea and in the air, at the same time as the USA was increasing its own forces. At the end of June 1942 the Japanese high command was compelled to issue orders to switch over to the defensive along the line extending from the Aleutian Islands, through Wake, to the Marshalls, Gilberts, Solomons, New Guinea, Timor, Java, Sumatra, and the Andaman and Nicobar Islands.

Campaign of 1942–43. During the second half of 1942, neither side had sufficient forces at their disposal for a major offensive, and only local operations continued for the purpose of improving the front line. A Japanese offensive in southeastern New Guinea, aimed at Port Moresby, from August to October 1942 ended in failure. In August 1942 the Allied armed forces began a stubborn battle for the island of Guadacanal in the Solomons, which ended in February 1943 with the capture of the island. They also conducted an offensive with limited forces in southeastern New Guinea.

The American command concentrated on building up their forces at a stepped-up pace. Work proceeded on raising and repairing those ships that had been sunk at Pearl Harbor, on the construction of new ships (especially aircraft carriers), on the formation of a large number of units and task groups, on the construction of air and naval bases, and on the accumulation of materiel. All of this allowed the Allied command in the summer of 1943 to proceed to carry out a strategic plan of offensive actions, which consisted in the sequential capture in the east of the Gilbert and Marshall Islands and in the west of the Solomon Islands, the Bismarck Archipelago, New Britain, and eastern New Guinea for the purpose of establishing bases and preparing for a subsequent offensive against the Caroline, Mariana, and Philippine islands. The offensive began in June 1943, and by the end of the year Allied troops, after fierce combat, had occupied the Gilbert and Solomon Islands (except for the island of Bouganville, where fighting continued until the end of the war), along with western New Britain and southeastern New Guinea. In the northern Pacific, American troops recovered the Aleutian islands of Attu and Kiska during the period May-August 1943.

The year 1943 saw the turning point in the course of the war in the Pacific. The USA and Great Britain recovered from their defeats of 1941–42, shifted the balance of forces in their favor, and seized the strategic initiative. The defeats suffered by Nazi Germany on the Soviet-German front and the capitulation of Fascist Italy also facilitated the change of situation in the Pacific theater of operations.

Campaign of 1944–45. By the beginning of 1944, the Allies had set up a command of Allied forces in the central Pacific, headed by Admiral C. Nimitz (the Fifth Fleet, the Seventh Army Air Corps, and two corps of Marines) and a command of Allied forces in the southwestern Pacific, headed by General D. MacArthur (the Seventh Fleet, the American Sixth and the Australian First armies, and the Fifth and Thirteenth Army air forces). These forces were opposed by the Japanese Thirty-first, Seventeenth, and Eighteenth armies and by the main forces of the Combined Fleet. The balance of forces (counting Japan’s naval forces stationed at home and in the South Sea zone) was in favor of the Allied forces: in personnel by a factor of 1.5, in air power by a factor of three, in battleships by a factor of two, in aircraft carriers by a factor of three, and in other classes of ships by a factor ranging from 1.5 to two.

The plan of the Allied command for 1944 called for landing operations to capture the Marshall, Caroline, and Mariana Islands and New Guinea, for the purpose of preparing staging areas for subsequent offensives and to establish air bases for strikes against the Japanese homeland.

From Feb. 1 to 23, 1944, American troops fought for and captured the Marshall Islands, from June 15 to August 10 the Marianas, and from September 15 to October 12 the western Carolines. The struggle for northern New Guinea continued from January through September 1944. In Burma, Japanese troops began an offensive against Assam in March 1944 (the Imphal Operation), which after four months of fighting ended in utter failure. The Allied troops undertook a counteroffensive, and by the end of the year they had recaptured most of northern Burma. In 1944 the Japanese conducted active operations in China, where in the course of the Honan (April 17-May 25), Hupeh-Hunan (May 27-August 10), and Kwangsi (Sept. 1,1944-January 1945) operations the Japanese completely split the land communication between the northern and southern regions of China.

On the whole, however, by the end of 1944 the situation had sharply changed in favor of the Allies. Troops of the Japanese Thirty-first, Seventeenth, and Eighteenth armies were blockaded on islands in the central and southwestern Pacific. Japan’s most important sea-lanes were under the control of the Allied armed forces.

On Oct. 17, 1944, Allied troops began the Philippine landing operation, involving the Sixth and units of the Eighth American armies (14 divisions), the Fifth and Thirteenth Army air forces (approximately 800 airplanes), and the Third and Seventh fleets (12 battleships, 34 aircraft carriers with 1,280 airplanes, 23 cruisers, 113 destroyers, 29 submarines, 438 transport and auxiliary craft). The Philippine Islands were defended by the Japanese Fourteenth and Thirty-fifth armies (seven infantry divisions, one tank division, and five brigades; during the period from October to December another four divisions arrived), the Fourth Air Army (600 airplanes), and the Combined Fleet (nine battleships, four aircraft carriers with 116 airplanes, 20 cruisers, 32 destroyers, and 17 submarines).

After a three-day air and artillery bombardment, landings were made on the island of Leyte on October 20, and by December 25 it was completely cleared of Japanese troops. During the fighting for Leyte naval battles took place in the Philippine area from October 23 to 25; in these actions the Japanese Fleet suffered heavy losses (three battleships, four aircraft carriers, ten cruisers, 11 destroyers, and two submarines). These battles ensured that subsequent landings by American troops on the other islands of the Philippine Archipelago would be unhindered. On Jan. 9,1945, American troops landed on the island of Luzon, and after stubborn fighting they took Manila on March 4. During March and April landings were made on the islands of Mindanao, Panay, Negros, and others. By mid-May, military operations in the Philippines were, in effect, concluded, although the total clearing out of small Japanese detachments was not completed until August 15.

Possessing ever-greater supremacy in forces and equipment (including overwhelming superiority in ships and aircraft), the American armed forces in intense battles during 1945 smashed the stubborn resistance of Japanese troops and captured the islands of Iwo Jima (February 19-March 16) and Okinawa (April 1-June 21). In these battles, however, the American fleet suffered considerable losses from kamikaze attacks. During the first half of 1945, Allied troops successfully advanced in Burma. However, Japan did not intend to capitulate and was preparing to give “general battle” on the territory of its homeland.

By the summer of 1945, Japan had increased its armed forces to 7.2 million men (including 5.5 million in the land army): 169 infantry and four tank divisions, 95 infantry and nine tank brigades, more than 10,000 aircraft (including half that were set aside for the kamikaze), and about 500 combat ships.

The Allied armed forces were preparing to invade the Japanese home islands as late as the end of 1945 or the beginning of 1946. However, the entrance of the USSR on Aug. 9, 1945, into the war in the Pacific placed Japan in a hopeless position and made it impossible for Japan to continue the war. On Aug. 6 and 9, 1945, upon the orders of President H. Truman, the Americans dropped atomic bombs on Hiroshima and Nagasaki; this action was not called for by military necessity and resulted in enormous destruction and countless victims among the peaceful population. During the course of the Manchurian Operation of 1945, Soviet troops took only a brief time to smash the Japanese Kwantung Army. Deprived of its most battle-ready group of forces on the Asian continent, as well as its important military-industrial base, Japan was compelled to surrender on Sept. 2,1945.

Casualties. During the Pacific campaigns the Japanese armed forces lost more than 893,000 men killed, along with 11 battleships, 21 aircraft carriers, 39 cruisers, 130 destroyers, and 130 submarines. In the Pacific fighting the USA lost more than 160,000 men, including about 29,000 killed, about 6,000 who later died from wounds, and approximately 38,000 missing in action. The US Navy lost two battleships, 11 aircraft carriers, ten cruisers, 70 destroyers, and 56 submarines.