The War in Eastern Asia

When Japan went to war with the United States, Great Britain, and the Netherlands in December 1941, she was already well established on the Asian mainland from Manchuria in the north to Indochina in the south. Since she possessed sovereignty over Taiwan (Formosa) and the Penghu Islands (Pescadores), she was poised to strike quickly toward the so-called Southern Regions, which included the Philippines, Borneo, Celebes, Java, Sumatra, Malaya, Thailand (Siam), and Burma, an area rich in such raw materials as oil, rubber, tin, and many other products of which she was desperately short. Of the 51 infantry divisions which composed the Japanese Army in 1941, 43 were committed to the Asian mainland: 13 to Manchuria, 2 to Korea, 25 to China, 2 to Indochina, and 1 to the island of Hainan. In addition, 2 of her 5 air divisions were also committed to Asia. She had therefore only a comparatively small force available to undertake the capture of the Southern Regions. The attacks on the Philippines and the Netherlands East Indies are discussed in section 9. War in the Southern and Southwestern Pacific, and this section therefore deals only with operations on the Asian mainland: Thailand, Malaya, Burma, China proper, and Manchuria. A division from China was given the task of seizing Hong Kong; the Twenty-Fifth Army, consisting of 4 divisions (of which only 3 were used) and an air division, was allotted to neutralize Thailand, Malaya, and capture the British naval base at Singapore; and the Fifteenth Army, consisting of 2 divisions and an air division, was assigned the job of occupying southern Burma.

Japanese Advance in Southeast Asia: 1941-1942

The invasion of Hong Kong began early on Dec. 8, 1941 (local time). The small garrison of this isolated outpost, consisting of two British, two Canadian, and two Indian battalions, attempted to defend the New (Leased) Territories on the mainland, but by December 13 had to withdraw to Hong Kong Island. The Japanese landed on its northern shores on the night of December 18-19 and gradually forced the garrison into the western part of the highly populated island. With no hope of reinforcement or relief and having suffered severe losses, the garrison surrendered on December 25. This freed the Japanese division to join the Sixteenth Army for the invasion of the Dutch territories farther south.

In the early hours of December 8 (local time), the Twenty-Fifth Army occupied Bangkok, thereby gaining control of Thailand, and landed a division at Songkhla (Singora) on the Kra Peninsula and part of another at Kota Bharu in northeastern Malaya. The Japanese quickly gained air supremacy, since their aircraft were far superior to and outnumbered the obsolescent Royal Air Force (RAF) planes. Two days later, Japanese torpedo bombers sank off the east coast of Malaya the Repulse and the Prince of Wales, the only two British capital ships in Eastern waters. This success ensured the Japanese complete control of the South China Sea. The British garrison of Malaya consisted of the Indian 3d Corps (two newly raised and semitrained divisions), which held northern Malaya, and an understrength Australian division, which held northern Johore. Constantly outflanked by infiltration through jungle-covered country and by landings on the coast behind it, the 3d Corps proved to be no match for the highly trained and experienced Japanese divisions and was forced to withdraw southward. The Japanese occupied Penang on December 19, and Kuala Lumpur on Jan. 11, 1942. Despite a stand in northern Johore by the Australians, they had driven the mauled and dispirited defenders back into Singapore Island by January 31. Although the garrison had been reinforced by two hastily dispatched and almost untrained Indian brigades and, at the last moment, by a British division diverted while at sea on its way to Egypt, the defense of the island, by then isolated by sea and air, was a hopeless task. The Japanese landed three divisions on February 8-9, and by February 13 had forced the remnants of the garrison back into a tight perimeter ringed around Singapore itself. With the city and its large Chinese and Malayan population under heavy artillery fire, water supplies cut off, and the troops short of ammunition, the garrison surrendered on February 15. In conquering Malaya, the Japanese had gained an entrance into the Bay of Bengal and the use of the Singapore naval base.

The invasion of Burma began on Dec. 16, 1941, when a small Japanese detachment occupied unopposed Victoria Point at its southern extremity; in mid-January other detachments occupied points on the Tenasserim coast. The small Burma Army was reinforced during January with what India could spare, but when the main invasion began it consisted of only two ill-equipped divisions, composed of British, Indian, and Burmese troops, supported by a very small air force, which included a squadron from Brig. Gen. (later Maj. Gen.) Claire L. Chennault's American Volunteer Group (Flying Tigers) in China. On January 20, two Japanese divisions crossed the Thai frontier east of Moulmein. Outflanking and outmaneuvering the Indian division facing them, they captured Moulmein on January 31, and by February 24 had forced the defenders back across the Sittang River.

In December 1941, Generalissimo Chiang Kai-shek, anxious lest the Burma Road, along which lend-lease supplies were reaching China from Rangoon, should be cut, had offered Chinese troops to assist in the defense of Burma. Their entry into Burma from the north in mid-February enabled the other division of the Burma Army (now reinforced by an armored brigade and other troops) to move south to help in the defense of Rangoon. The advance of the Japanese was, however, too rapid: they drove a wedge between the two divisions before a junction could be made, and on March 5 captured Pegu. Rangoon could no longer be held and, after some hesitation, was evacuated on March 7. Its garrison, escaping somewhat luckily from the encircling Japanese forces, withdrew up the Irrawaddy toward Prome.

The defense of central and northern Burma now rested on the Burma Army (two weak divisions) in the Irrawaddy Valley, and on the Chinese Fifth and Sixth armies (equivalent in strength to two American divisions) in the Sittang Valley on the direct railway from Rangoon to Mandalay. The Chinese were under the command of Lt. Gen. (later Gen.) Joseph W. Stilwell, who had also been appointed commanding general of the American China-Burma-India (CBI) theater in February 1942. The possession of Rangoon and the cessation of hostilities in Malaya enabled the Japanese to reinforce the Fifteenth Army in Burma with two fresh divisions, two tank regiments, considerable artillery, and a number of air regiments. They quickly advanced toward Mandalay in an attempt to destroy the defenders in the loop of the Irrawaddy River. Having captured Toungoo on March 30, they drove rapidly north, passing round the Chinese left flank, and by the end of April had cut the Burma Road at Lashio. The Burma Army had no alternative but to withdraw across the Irrawaddy. Burma could now no longer be held. The Burma Army and two Chinese divisions withdrew into Assam, the former by way of Kalewa to Imphal and the latter from Myitkyina to Ledo. The rest of the Chinese armies withdrew eastward across the Salween River into China. By the end of May 1942, the Japanese were in control of the whole of Burma and had occupied the Andaman and Nicobar Islands. They had thus attained in five months all their objectives and secured the western end of their long defensive perimeter around the Southern Regions.

With the control of the Strait of Malacca and the Bay of Bengal in their hands, the Japanese sent part of their naval forces, including aircraft carriers, into the Indian Ocean for a short time early in April to bomb Colombo and the naval base at Trincomalee in Ceylon and to raid the shipping routes along the east coast of India. Neither the British nor the Japanese were seeking a fleet action but, before the enemy force withdrew to Singapore, its aircraft had sunk two British cruisers, a small aircraft carrier, two destroyers, and a corvette and had accounted for approximately 100,000 tons of merchant shipping.

The loss of Burma and of the command of the sea and air in the Bay of Bengal left India wide open to invasion by land or sea. Since the best Indian formations had been sent to Iraq and Egypt and the equivalent of three divisions had been lost in Malaya and Burma, there was little with which to undertake her defense until her many newly raised divisions were trained, equipped, and ready for battle. Strenuous efforts were therefore made to build up forces for her defense and that of Ceylon. Three British divisions were diverted from the Middle East theater, and an African division was sent from East Africa. A beginning was also made in the buildup of a large Allied strategic and tactical air force, including the United States Tenth Air Force, and the India-Burma Division of the United States Air Transport Command to ferry supplies from Assam across the "hump to China, which was now cut off from all land access from the west. This entailed an enormous program of airfield construction in Bengal, Assam, and elsewhere in India, which stretched Indian engineering resources to their limit. Faced with the defense of her eastern frontier (an eventuality which had never been envisaged), India had also to reorientate her logistical organization and improve the very poor rail and river communications from Calcutta to eastern Bengal and Assam. In her efforts to do this she was hampered by having sent much of her river and coastal shipping and a large proportion of her meter-gauge railway locomotives and rolling stock to Iraq to help in its defense. The buildup therefore could only be accomplished over a longish period of time.

With the American naval victories of the Coral Sea in May and Midway in June 1942, the danger to India passed, and the main problem now facing the Allies was how to keep China in the war. To reach Kunming by road from Assam necessitated the reoccupation of northern and central Burma and the building of a road from Ledo through Myitkyina and Bhamo to join the original Burma Road. Since to accomplish this would take considerable time, it was decided to increase deliveries of supplies by the air ferry route to a tonnage sufficient to supply the needs of Chennault's Fourteenth Air Force and reequip approximately 30 Chinese divisions. The Chinese troops who had reached India in 1942, gradually reinforced by men flown from China, were reformed, equipped, and trained by Stilwell, who aimed at producing three elite Chinese divisions (each of 10,000 men) with tank and artillery support.

Operations in Burma: 1942-1943

Gen. (later Field Marshal) Sir Archibald Wavell (later 1st Earl Wavell), the commander in chief in India, made every effort to take the offensive to recapture Burma as soon as practicable, but the means were not to hand until time allowed his land and air forces to be assembled and trained and his communications to the eastern frontier built up. Nevertheless, he launched an offensive in October 1942 by one division to capture Akyab in coordination with an amphibious assault on the port. Maungdaw and Buthidaung were occupied on December 17, but the formation earmarked for the amphibious assault and its landing craft were delayed by extended operations to wrest Madagascar from the control of supporters of the Vichy French government. Wavell therefore decided to continue with the land advance and, when within striking distance of Akyab, to launch a short-range amphibious attack. The Japanese had meanwhile brought their forces in Arakan up to divisional strength, and early in March 1943 halted the land advance too far to the north of the port to make a short-range amphibious operation possible. They then launched a counteroffensive and by the break of the monsoon in May had recaptured Buthidaung and Maungdaw. Although Wavell's effort had failed, it brought to light defects in the organization and training of the rapidly expanding Indian Army. These were eliminated, and by the end of 1943 the British-Indian divisions had reached a pitch of training which made them equal to the Japanese.

In July 1942, Wavell formed a long-range penetration brigade (Chindits) under the command of Brig. (later Maj. Gen.) Orde C. Wingate. On Feb. 14, 1943, the Chindits, some 3,000 strong, crossed the Chindwin River and, supplied by air, penetrated deep into Burma without meeting much opposition and damaged the railway south of Indaw. Wingate then crossed the Irrawaddy into a somewhat waterless area, but its many roads and tracks enabled the Japanese to surround his force, which had to disperse and get back as best it could. By early June, only 2,200 men had got out of Burma to Assam or China. This incursion had little strategic value in itself, but it gave a considerable moral fillip to Britain and India and showed clearly that troops in jungle country could be supplied by air. Its greatest effect, however, was that it made the Japanese decide to improve their defensive positions in Burma by taking the offensive toward Assam, a decision which was to prove fatal.

Campaigns in Burma and China: 1943-1944

In November 1943, the Anglo-American Southeast Asia Command (SEAC) was formed with Adm. Lord Louis Mountbatten (later 1st Earl Mountbatten of Burma) as supreme commander, and General Stilwell as his deputy, with the object of controlling all operations in Southeast Asia. In December, the United States Tenth Air Force and the RAF wings in India were combined into the Eastern Air Command under Maj. Gen. (later Lt. Gen.) George E. Stratemeyer. Meanwhile, plans were made to establish the 20th Bomber Command, equipped with long-range B-29 aircraft, at Chengtu in Szechwan Province, China, from where Manchuria and the Japanese mainland could be bombed.

The plans for the 1944 campaign prepared by the supreme commander included a combined thrust by Stilwell's Chinese forces from Ledo toward Myitkyina, by British-Indian forces across the Chindwin toward Indaw, and by the Chinese Yunnan armies across the Salween with the object of reoccupying northern Burma and opening a land route to China. A subsidiary attack was to be made in Arakan to capture Akyab and, if resources allowed, the Andaman Islands. Resources, however, did not permit an amphibious operation to be mounted in the Indian Ocean, and Chiang Kai-shek refused to commit his Yunnan armies across the Salween. The plans for 1944 had therefore to be reduced to a land advance toward Akyab, a drive down the Hukawng Valley toward Myitkyina, and an incursion by the Chindits (now enlarged to six brigades and known as Special Force) to the Indaw area to cut the enemy communications to the north and so assist Stilwell's thrust on Myitkyina. The Japanese, on the other hand, having decided to take the offensive, planned to advance in March 1944 across the Chindwin to capture the British base at Imphal, and to attack in Arakan in February to forestall the expected Allied advance in that area.

At the end of the monsoon the Indian 15th Corps of the Fourteenth Army under the command of Lt. Gen. (later Field Marshal) Sir William Slim (later 1st Viscount Slim) was gradually approaching the strong defensive positions in Arakan covering Maungdaw and Buthidaung when, on February 4, the Japanese launched their offensive. They passed approximately 5,000 men behind the forward Indian divisions, thus cutting their communications. Supplied by air, these stood firm, and reserves brought forward threw back the Japanese with heavy loss. The British offensive was then resumed, and by the break of the monsoon in May the Japanese had been driven out of all their main defenses covering Akyab.

The Japanese offensive toward Imphal was launched by the Fifteenth Army in mid-March, but, on the assumption that Imphal would be captured in three weeks, inadequate logistical plans for its maintenance had been made, a mistake which was to prove disastrous. In accordance with the Fourteenth Army's prearranged plan, the Indian 4th Corps withdrew to prepared positions covering the Imphal plain as soon as the enemy crossed the Chindwin. The corps was isolated from India when the Imphal road was cut on March 29. Kohima was attacked on April 4 and surrounded by April 8. A division was flown into Imphal from Arakan, and the Indian 33d Corps was brought forward from India and concentrated at Dimapur. The Allies had by now gained air supremacy over Burma, and, supplied by an airlift, the 4th Corps was able to hold its position around Imphal and in May to begin a counteroffensive, while the 33d Corps, after relieving the Kohima garrison, took the offensive southward. By the end of June, the two corps had met, and the Imphal road was reopened. The defeated Japanese Fifteenth Army, short of food and ammunition, retreated to the Chindwin in considerable disorder.

Stilwell had begun his advance from Ledo toward Myitkyina in January. On orders from Chiang, the Chinese divisions did not press forward as fast as they might, but progress was made thanks to Merrill's Marauders (the 5307th Composite Unit led by Maj. Gen. Frank D. Merrill and the American counterpart of the Chindits), and by the end of March the Hukawng Valley had been cleared and entry into the Mogaung Valley secured. On April 28, the Marauders, reinforced by some Chinese regiments, began to move east across the mountains and then south to capture Myitkyina from the north by surprise. On May 17, this force occupied the Myitkyina airfield, but its exhaustion was such that, despite reinforcements brought in by air, it was unable to drive the Japanese from the town, and a dour struggle began that lasted 11 weeks.

To assist Stilwell's advance, three brigades of Special Force were moved into Burma by air and by march route. By the end of March 1944, approximately 12,000 men, supplied entirely by air, were established around Indaw and had formed a block north of the town on the road and railway leading to Mogaung, thus effectively cutting the communications of the enemy forces facing Stilwell. The Japanese made repeated unsuccessful attempts to break the block, but it became evident early in April not only that the block might be overwhelmed by a newly arrived Japanese division, but that Special Force could not be maintained at Indaw during the monsoon. It was therefore ordered to move north at the end of April, establish a new block nearer Mogaung, and come under Stilwell's command beginning on May 17.

By threatening to withdraw aid for the reequipment of his armies, the Americans at last obtained Chiang's agreement to the Yunnan armies taking the offensive across the Salween on April 10. This offensive, however, failed to help Stilwell to capture Myitkyina, for an inferior Japanese force brought the Chinese to a halt by the end of June before a line of defended walled towns not more than 20 miles west of the Salween.

Special Force established its new block south of Mogaung on May 7 but was forced to abandon it with heavy loss May 25. The Japanese were now free to reinforce Kamaing or Myitkyina but did not move quickly enough to do either. Stilwell occupied Kamaing on June 16, and a brigade of Special Force, with some assistance from a Chinese division, occupied Mogaung on June 26. Stilwell was now able to use the road to Myitkyina; his forces were reinforced and finally occupied the town on August 3. The capture of Myitkyina was of great value for, once airfields had been constructed and a pipeline built from Ledo to them, the air ferry could operate into China without flying across the "hump.

There was little more than sporadic fighting in China during 1942 and 1943. By the beginning of 1944, Chennault had established a base for the B-29's at Chengtu and a chain of airfields in eastern China astride the Hankow-Canton railway, from which the Fourteenth Air Force could support the Chinese armies. Since these latter airfields constituted a danger, the Japanese decided to eliminate them. In April and May, they cleared the Peiping (Peking)-Hankow railway, and at the end of May began to advance southward. Despite the support of the Fourteenth Air Force and at times of the B-29's, the Chinese armies were no match for the Japanese. By mid-December, assisted by an advance westward from Canton, the Japanese had occupied all but two of the American airfields in eastern China, had made contact with their garrison in Indochina, and had created a threat to both Kunming and Chungking. Meanwhile, in June, the B-29's from Chengtu had begun to bomb targets in Manchuria and western Japan.

Recovery of Burma and Final Operations Against Japan: 1944-1945

In October 1944, Stilwell was recalled to Washington, and the CBI theater was divided. Maj. Gen. (later Lt. Gen.) Albert C. Wedemeyer replaced Stilwell as commanding general of the China theater and Lt. Gen. Daniel I. Sultan took command of the Burma-India theater, which remained part of SEAC. Soon after taking up his command, Wedemeyer, conscious of the threat to Chungking and Kunming, advised Chiang Kai-shek to concentrate a force of 30 Chinese divisions to meet it. To provide a trained nucleus for this force, he asked for the eventual return to China of all the Chinese divisions (by now numbering 5) operating in northern Burma; 2 were sent him in January 1945.

In Burma the Fourteenth Army relentlessly pursued the defeated Japanese throughout the monsoon. Despite appalling climatic conditions, which turned roads and tracks into quagmires, Kalewa was captured and bridgeheads were established across the Chindwin at many points by the first week in December 1944. Slim was now ready to advance into central Burma. He sent his 33d Corps in a wide sweep toward the Irrawaddy with Mandalay as its objective, and with great secrecy passed the 4th Corps southward from Kalewa to Pakokku, with Meiktila on the main enemy communications between Rangoon and Mandalay as its objective. By Feb. 1, 1945, supplied almost entirely by air, the Fourteenth Army had closed up to the Irrawaddy from a point 40 miles north of Mandalay, where it had seized bridgeheads across the river, to Pakokku 140 miles farther downstream. On the Arakan coast the 15th Corps began to advance as soon as the monsoon abated and occupied Akyab, which had been abandoned by the Japanese two days earlier, on January 3. An amphibious attack was launched on Ramree Island on January 21, and the island was finally occupied during February. Airfields were rapidly built at Akyab and on Ramree Island to make it possible for the Fourteenth Army to be supplied by air in its drive toward Rangoon from the Irrawaddy.

In northern Burma the southward advance from Myitkyina, begun by Stilwell in October 1944, made slow progress, and it was not until December 15 that Bhamo was occupied. Sultan, who now had an American brigade (which incorporated the Marauders), a British division, and three Chinese divisions, pressed on and made junction with the Yunnan armies on the old Burma Road on Jan. 20, 1945. The road from Ledo to China was now clear, and the first convoy from India passed along it to reach Kunming on February 4. Work was immediately begun on extending the Ledo-Myitkyina oil pipeline to Kunming. Meeting with little opposition, for the Japanese were forced by the threat to Mandalay to withdraw southward, Sultan's forces occupied Lashio on March 7. Meanwhile, using Myitkyina as a staging post, the Air Transport Command had doubled the monthly air deliveries to China. With this increase and a road and pipeline from India, China was no longer isolated from her allies.

The Japanese sea communications with the Southern Regions, already precarious owing to the activities of the American submarine fleet, were completely severed when Leyte and Luzon in the Philippines were reoccupied in the winter of 1944-1945. The Japanese armies in the Southern Regions, forced to exist on the countries they had occupied and such reserves of war material as they had stored, withdrew divisions from outlying territories, including Burma, to reinforce Indochina, now open to invasion from the Philippines, and thus weakened their ability to defend the other areas.

By the end of February 1945, a fleet of river craft had been assembled on the Chindwin at Kalewa to supplement air supply and, with adequate supplies ensured, Slim began to cross the Irrawaddy in mid-February. The 4th Corps captured Meiktila by surprise on March 3, and shortly thereafter Mandalay was invested from both the north and the south. In a desperate attempt to stave off final defeat, the Japanese concentrated their remaining forces in Burma and launched a counteroffensive to recapture Meiktila; a fierce battle raged throughout March, but by the end of the month Mandalay had been captured, and the Japanese had been thrown back with very heavy losses, their armies losing all cohesion. This offensive proved to be their last in Burma. Slim immediately resumed the pursuit toward Rangoon along both the main railway and the Irrawaddy. Toungoo was occupied on April 22 and Prome on May 2, and Pegu was reached on April 29. To ensure that Rangoon was occupied before the monsoon broke, an amphibious landing, preceded by a parachute drop, was made near the mouth of the Rangoon River on May 2, and the city, which had been hastily evacuated by the Japanese a few days before, was entered without opposition on May 3. The campaign for the reoccupation of Burma was now over, except for extensive mopping-up operations, and SEAC began to prepare for the invasion of Malaya. With the virtual end of the Burma campaign, all the American and Chinese resources remaining in India and Burma were gradually transferred to China, and plans were made in Chungking for an offensive by 39 divisions to capture a port in eastern China in the fall of 1945.

The swift progress of the American offensive in the Pacific . War in the Central and Northern Pacific culminated in the capture of Iwo Jima in March and of Okinawa in June 1945. The Americans now had forward bases for an invasion of Japan, and the Japanese were forced to withdraw troops from Manchuria, Korea, and China to defend their homeland. In China, to forestall any amphibious landing, they began to withdraw toward its coast and concentrated their forces in the Canton area, the lower Yangtze Valley, and Shanghai, thus enabling the Chinese, with American assistance, to reoccupy many of the airfields in eastern China which had been lost the previous year.

Japan opened negotiations for peace on August 10 after atomic bombs had been dropped on Hiroshima and Nagasaki on August 6 and August 9. On August 14, she surrendered unconditionally. The USSR declared war on Japan on August 8 (effective August 9) and, using a massive force of three strong army groups, invaded Manchuria, K