The Burma campaign was a series of battles fought in the British colony of Burma as part of the South-East Asian theatre of World War II. It primarily involved forces of the Allies (mainly from the British Empire and the Republic of China, with support from the United States) against the invading forces of the Empire of Japan. Imperial Japan was supported by the Thai Phayap Army, as well as two collaborationist independence movements and armies, The State of Burma and the Provisional Government of Free India. Nominally independent puppet states were established in the conquered areas and some territories were annexed by Thailand. In 1942 and 1943, the international Allied force in British India launched several failed offensives to retake lost territories. Fighting intensified in 1944, and British Empire forces peaked at around 1 million land and air forces. These forces were drawn primarily from British India, with British Army forces (equivalent to eight regular infantry divisions and six tank regiments), 100,000 East and West African colonial troops, and smaller numbers of land and air forces from several other Dominions and Colonies. These additional forces allowed the Allied recapture of Burma in 1945.
The campaign had a number of notable features. The geographical characteristics of the region meant that weather, disease and terrain had a major effect on operations. The lack of transport infrastructure placed an emphasis on military engineering and air transport to move and supply troops, and evacuate wounded. The campaign was also politically complex, with the British, the United States and the Chinese all having different strategic priorities. It was also the only land campaign by the Western Allies in the Pacific Theatre that proceeded continuously from the start of hostilities to the end of the war. This was due to its geographical location. By extending from South East Asia to India, its area included some lands which the British lost at the outset of the war, but also included areas of India wherein the Japanese advance was eventually stopped. The climate of the region is dominated by the seasonal monsoon rains, which allowed effective campaigning for only just over half of each year. This, together with other factors such as famine and disorder in British India and the priority given by the Allies to the defeat of Nazi Germany, prolonged the campaign and divided it into four phases: the Japanese invasion, which led to the expulsion of British, Indian and Chinese forces in 1942; failed attempts by the Allies to mount offensives into Burma, from late 1942 to early 1944; the 1944 Japanese invasion of India, which ultimately failed following the battles of Imphal and Kohima; and finally the successful Allied offensive which liberated Burma from late 1944 to mid-1945.
The campaign was also strongly affected from the political atmosphere which erupted in the South-East Asian regions occupied by Japan, who pursued the Pan-Asianist policy of a "Greater East Asia Co-Prosperity Sphere". These led to a Japanese-sponsored revolution during the initial invasion and the establishment of the State of Burma, whose Burma Independence Army had spearheaded the initial attacks against the country. The Provisional Government of Free India, with its Indian National Army, fought under Imperial Japan, especially during Operation U-Go in 1944. The INA had earlier collaborated with Nazi Germany. The dominating attitude of the Japanese militarist who commanded the army stationed in the country ultimately doomed the co-prosperity sphere as a whole, leading to local hopes for real independence fading and a revolt by the Burma National Army in 1945. On the Allied side, political relations were mixed for much of the war. The China Burma India Theater American-trained Chinese X Force led to cooperation between the two countries, but the clashing strategies proposed by General Joseph Stilwell and Chinese Generalissimo Chiang Kai-shek would lead to Stilwell's eventual removal from his position as American Commander of the theater. On the other hand, China–India relations were positive from the cooperative Burma Road, built to reach the Chinese Y Force and the Chinese war effort inside China, as well as from the missions over the extremely dangerous air route over the Himalayas, nicknamed "The Hump". The campaign would have a great impact on the independence struggle of Burma and India in the post-war years.
Japanese conquest of Burma
Japanese objectives in Burma were initially limited to the capture of Rangoon, the capital and principal seaport. This would close the overland supply line to China and provide a strategic bulwark to defend Japanese gains in British Malaya and the Dutch East Indies. The Japanese Fifteenth Army under Lieutenant General Shōjirō Iida, initially consisting of only two infantry divisions, moved into northern Thailand (which had signed a treaty of friendship with Japan), and launched an attack over jungle-clad mountain ranges into the southern Burmese province of Tenasserim (now Tanintharyi Region) in January 1942.
In the face of the Japanese advances, huge numbers of Indians, Anglo-Indians, and Anglo-Burmese fled Burma, around 600,000 by the autumn of 1942. Perhaps 80,000 of those in flight would die from starvation, exhaustion and disease. Some of the worst massacres in Burma during World War II would be perpetrated not by the Japanese but by Burmese gangs linked to the Burma Independence Army.
The Japanese successfully attacked over the Kawkareik Pass and captured the port of Moulmein at the mouth of the Salween River after overcoming stiff resistance. They then advanced northwards, outflanking successive British defensive positions. Troops of the 17th Indian Infantry Division tried to retreat over the Sittaung River, but Japanese parties reached the vital bridge before they did. On 22 February, the bridge was demolished to prevent its capture, a decision that has since been extremely contentious.
The loss of two brigades of the 17th Indian Division meant that Rangoon could not be defended. General Archibald Wavell, the commander-in-chief of the American-British-Dutch-Australian Command, nevertheless ordered Rangoon to be held as he was expecting substantial reinforcements from the Middle East. Although some units arrived, counterattacks failed and the new commander of the Burma Army (General Harold Alexander) ordered the city to be evacuated on 7 March after its port and oil refinery had been destroyed. The remnants of the Burma Army broke out to the north, narrowly escaping encirclement.
On the eastern part of the front, in the Battle of Yunnan-Burma Road, the Chinese 200th Division held up the Japanese for a time around Toungoo, but after its fall the road was open for motorised troops of the Japanese 56th Division to shatter the Chinese Sixth Army to the east in the Karenni States and advance northward through the Shan States to capture Lashio, outflanking the Allied defensive lines and cutting off the Chinese armies from Yunnan. With the effective collapse of the entire defensive line, there was little choice left other than an overland retreat to India or to Yunnan.
Japanese advance to the Indian frontier
After the fall of Rangoon in March 1942, the Allies attempted to make a stand in the north of the country (Upper Burma), having been reinforced by a Chinese Expeditionary Force. The Japanese had also been reinforced by two divisions made available by the capture of Singapore and defeated both the newly organised Burma Corps and the Chinese force. The Allies were also faced with growing numbers of Burmese insurgents, and the civil administration broke down in the areas they still held. With their forces cut off from almost all sources of supply, the Allied commanders finally decided to evacuate their forces from Burma. On 16 April, in Burma, 7,000 British soldiers were encircled by the Japanese 33rd Division during the Battle of Yenangyaung and rescued by the Chinese 38th Division.
The retreat was conducted in very difficult circumstances. Starving refugees, disorganised stragglers, and the sick and wounded clogged the primitive roads and tracks leading to India. Burma Corps managed to make it most of the way to Imphal, in Manipur in India, just before the monsoon broke in May 1942, having lost most of their equipment and transport. There, they found themselves living out in the open under torrential rains in extremely unhealthy circumstances. The army and civil authorities in India were very slow to respond to the needs of the troops and civilian refugees.
Due to a lack of communication, when the British retreated from Burma, almost none of the Chinese knew about the retreat. Realising that they could not win without British support, some of the X Force committed by Chiang Kai-shek made a hasty and disorganised retreat to India, where they were put under the command of the American General Joseph Stilwell. After recuperating, they were re-equipped and retrained by American instructors. The rest of the Chinese troops tried to return to Yunnan through remote mountainous forests, and of these, at least half died.
Thai army enters Burma
In accordance with the Thai military alliance with Japan that was signed on 21 December 1941, on 21 March, the Thais and Japanese also agreed that the Karenni State and Shan States were to be under Thai control. The rest of Burma was to be under Japanese control.
The leading elements of the Thai Phayap Army under General J. R. Seriroengrit crossed the border into the Shan States on 10 May 1942. Three Thai infantry divisions and one cavalry division, spearheaded by armoured reconnaissance groups and supported by the Royal Thai Air Force, engaged the retreating Chinese 93rd Division. Kengtung, the main objective, was captured on 27 May. On 12 July, General Phin Choonhavan, who would become the Thai military governor of the occupied Shan State later in the war, ordered the 3rd Division of the Phayap Army from the southern part of the Shan State to occupy Karenni State and expel the Chinese 55th Division from Loikaw. The Chinese troops could not retreat because the routes to Yunnan were controlled by Axis forces, and many Chinese soldiers were captured. The Thais remained in control of the Shan States for the remainder of the war. Their troops suffered from supply shortages and disease, but were not subjected to Allied attacks.
Allied setbacks, 1942–1943
The Japanese did not renew their offensive after the monsoon ended. They installed a nominally independent Burmese government under Ba Maw, and reformed the Burma Independence Army on a more regular basis as the Burma National Army under General Aung San. In practice, both government and army were strictly controlled by the Japanese authorities.
On the Allied side, operations in Burma over the remainder of 1942 and in 1943 were a study of military frustration. Britain could only maintain three active campaigns, and immediate offensives in both the Middle East and Far East proved impossible through lack of resources. The Middle East was accorded priority, being closer to home and in accordance with the "Germany First" policy in London and Washington.
The Allied buildup was also hampered by the disordered state of Eastern India at the time. There were violent Quit India protests in Bengal and Bihar, which required large numbers of British troops to suppress. There was also a disastrous famine in Bengal, which may have led to 3 million deaths through starvation, disease and exposure. In such conditions of chaos, it was difficult to improve the inadequate lines of communication to the front line in Assam or make use of local industries for the war effort. Efforts to improve the training of Allied troops took time, and in forward areas, poor morale and endemic disease combined to reduce the strength and effectiveness of the fighting units.
Nevertheless, the Allies mounted two operations during the 1942–1943 dry season. The first was a small offensive into the coastal Arakan Province of Burma. The Indian Eastern Army intended to reoccupy the Mayu peninsula and Akyab Island, which had an important airfield. A division advanced to Donbaik, only a few miles from the end of the peninsula, but was halted by a small but well-entrenched Japanese force. At this stage of the war, the Allies lacked the means and tactical ability to overcome strongly constructed Japanese bunkers. Repeated British and Indian attacks failed with heavy casualties. Japanese reinforcements arrived from Central Burma and crossed rivers and mountain ranges, which the Allies had declared to be impassable, to hit the Allies' exposed left flank and overrun several units. The exhausted British were unable to hold any defensive lines and were forced to abandon much equipment and fall back almost to the Indian frontier.
The second action was controversial. Under the command of Brigadier Orde Wingate, a long-range penetration unit known as the Chindits infiltrated through the Japanese front lines and marched deep into Burma, with the initial aim of cutting the main north–south railway in Burma in an operation codenamed Operation Longcloth. Some 3,000 men entered Burma in many columns. They damaged the communications of the Japanese in northern Burma, cutting the railway for possibly two weeks, but they suffered heavy casualties. Though the results were questioned, the operation was used to propaganda effect, particularly to insist that British and Indian soldiers could live, move and fight as effectively as the Japanese in the jungle, doing much to restore morale among Allied troops.
The balance shifts 1943–1944
From December 1943 to November 1944, the strategic balance of the Burma campaign shifted decisively. Improvements in Allied leadership, training and logistics, together with greater firepower and growing Allied air superiority, gave Allied forces the confidence they had previously lacked. In the Arakan, XV Indian Corps withstood, and then broke, a Japanese counterstrike, while the Japanese invasion of India resulted in unbearably heavy losses and the ejection of the Japanese back beyond the Chindwin River.
Allied plans
In August 1943, the Allies created South East Asia Command (SEAC), a new combined command responsible for the South-East Asian Theatre, under Admiral Lord Louis Mountbatten. The training, equipment, health and morale of Allied troops under British Fourteenth Army under Lieutenant General William Slim was improving, as was the capacity of the lines of communication in North-eastern India. An innovation was the extensive use of aircraft to transport and supply troops.
SEAC had to accommodate several rival plans, many of which had to be dropped for lack of resources. Amphibious landings on the Andaman Islands (Operation "Pigstick") and in Arakan were abandoned when the landing craft assigned were recalled to Europe in preparation for the Normandy Landings.
The major effort was intended to be by American-trained Chinese troops of Northern Combat Area Command (NCAC) under Stilwell, to cover the construction of the Ledo Road. Orde Wingate had controversially gained approval for a greatly expanded Chindit force, which was given the task of assisting Stilwell by disrupting the Japanese lines of supply to the northern front. Chiang Kai-shek had also agreed reluctantly to mount an offensive from Yunnan.
Under the British Fourteenth Army, the Indian XV Corps prepared to renew the advance in Arakan province, while IV Corps launched a tentative advance from Imphal in the centre of the long front to distract Japanese attention from the other offensives.
Japanese plans
About the same time that SEAC was established, the Japanese created the Burma Area Army under Lieutenant General Masakazu Kawabe, which took under command the Fifteenth Army and the newly formed Twenty-Eighth Army.
The new commander of Fifteenth Army, Lieutenant General Renya Mutaguchi, was keen to mount an offensive against India. Burma Area Army originally quashed this idea, but found that their superiors at Southern Expeditionary Army Group HQ in Singapore were keen on it. When the staff at Southern Expeditionary Army were persuaded that the plan was inherently risky, they in turn found that Imperial General Headquarters in Tokyo was in favour of Mutaguchi's plan.