The U Go offensive, or Operation C (ウ号作戦 U Gō sakusen), was the Japanese offensive launched in March 1944 against forces of the British Empire in the northeast Indian regions of Manipur and the Naga Hills (then administered as part of Assam). Aimed at the Brahmaputra valley, through the two towns of Imphal and Kohima, the offensive along with the overlapping Ha Go offensive was one of the last major Japanese offensives during the Second World War. The offensive culminated in the Battles of Imphal and Kohima, where the Japanese and their allies were first held and then pushed back.
In 1942, the Japanese Army had driven the British, Indian and Chinese troops out of Burma. When heavy monsoon rains stopped campaigning, the British and Indian troops had occupied Imphal, the capital of Manipur state. This lay in a plain astride one of the few practicable routes over the jungle-covered mountains which separated India and Burma. The Japanese commander in Burma, Lieutenant General Shōjirō Iida, was asked for his opinion on whether a renewed advance should be made into India after the rains ended. After conferring with his divisional commanders, Iida reported that it would be unwise to do so, because of the difficult terrain and supply problems.
During the year and a half which followed, the Allies reconstructed the lines of communication to Assam, in north-east India. The United States Army (with large numbers of Indian labourers) constructed several airbases in Assam from which supplies were flown to the Nationalist Chinese government under Chiang Kai-shek and American airbases in China.This air route, which crossed several mountain ranges, was known as the Hump. The Americans also began constructing the Ledo road, which they intended would form a land link from Assam to China.
In mid-1943, the Japanese command in Burma had been reorganised. General Iida was posted back to Japan and a new headquarters, Burma Area Army, was created under Lieutenant-General Masakasu Kawabe. One of its subordinate formations, responsible for the central part of the front facing Imphal and Assam, was the Fifteenth Army, whose new commander was Lieutenant-General Renya Mutaguchi.
From the moment he took command, Mutaguchi forcefully advocated an invasion of India. Rather than seeking a mere tactical victory, he planned to exploit the capture of Imphal by advancing to the Brahmaputra River valley, thereby cutting the Allied supply lines to their front in northern Burma, and to the airfields supplying the Nationalist Chinese. His motives for doing so appear to be complex. In late 1942, when he was consulted by Lieutenant General Iida about the advisability of continuing the Japanese advance, he had been particularly vocal in his opposition, as the terrain appeared to be too difficult and the logistic problems seemed impossible to overcome. He had thought at the time that this plan originated at a local level, but was ashamed of his earlier caution when he found that Imperial Army HQ had originally advocated it.
By design or chance, Mutaguchi had played a major part in several Japanese victories, ever since the Marco Polo Bridge incident in 1937. He believed it was his destiny to win the decisive battle of the war for Japan. Mutaguchi was also goaded by the first Chindit long-range penetration expedition launched by the British under Orde Wingate early in 1943. Wingate's troops had traversed terrain which Mutaguchi had earlier claimed would be impassable to the Japanese 18th Division which he commanded at the time.The Allies had widely publicised the successful aspects of Wingate's expedition while concealing their losses to disease and exhaustion, misleading Mutaguchi and some of his staff as to the difficulties they would later face.
Between 24 June and 27 June 1943, a planning conference was held in Rangoon. Mutaguchi's Chief of Staff, Major General Todai Kunomura, presented Mutaguchi's plan, but was brusquely overruled. The staff of Burma Area Army objected to Kunomura pre-empting their own limited plans to push the Japanese forward defensive lines a short distance into the mountainous frontier with India.
Mutaguchi's plan was nevertheless examined. Lieutenant General Eitaro Naka, (Burma Area Army's Chief of Staff), Major General Masazumi Inada, (the Vice Chief of Staff of Southern Expeditionary Army Group) and even Lieutenant General Gonpachi Kondo from Imperial General Headquarters all pointed out tactical and logistical weaknesses in Mutaguchi's plan. However, Lieutenant General Kawabe did not expressly forbid Mutaguchi to carry out his ideas.
At subsequent exercises at Fifteenth Army's headquarters in Maymyo and at Southern Expeditionary Army Group's headquarters in Singapore, Lieutenant General Naka appeared to have been won over to Mutaguchi's ideas. Lieutenant General Inada was still opposed, but put forward to Kunomura and Major Iwaichi Fujiwara (one of Mutaguchi's staff officers) the apparently frivolous idea of attacking into the Chinese province of Yunnan instead. However, Inada was removed from Southern Expeditionary Army on 11 October 1943, after being made the scapegoat for failures to comply with an agreement to cede territories to Thailand which, under Field Marshal Plaek Pibulsonggram, was allied to Japan.
After another map exercise in Singapore on 23 December 1943, Field Marshal Hisaichi Terauchi (Commander in Chief of Southern Expeditionary Army Group) approved the plan. Inada's replacement, Lieutenant General Kitsuju Ayabe, was despatched to Imperial Army HQ to gain approval. Prime Minister Hideki Tōjō gave final sanction after questioning a staff officer over aspects of the plan from his bath.
Once this decision was taken, neither Lieutenant General Kawabe nor Field Marshal Terauchi were given any opportunity to call off Mutaguchi's attack, codenamed U-GO or Operation C (ウ号作戦), nor to exercise much control over it once it was launched.
To some extent, Mutaguchi and Tojo were influenced by Subhas Chandra Bose, who led the Azad Hind, a movement which was dedicated to freeing India from British rule. Bose was also commander in chief of the movement's armed forces, the Azad Hind Fauj or Indian National Army (INA). The INA was composed mainly of former prisoners of war from the British Indian Army who had been captured by the Japanese after the fall of Singapore, and Indian expatriates in South East Asia who had decided to join the nationalist movement.
Bose was eager for the INA to participate in any invasion of India, and persuaded several Japanese that a victory such as Mutaguchi anticipated would lead to the collapse of British rule in India. The idea that their western boundary would be controlled by a more friendly government was attractive to the Japanese. It would also have been consistent with the idea that Japanese expansion into Asia was part of an effort to support Asian government of Asia and counter western colonialism.
The Allies were preparing to take the offensive themselves in early 1944. The Indian XV Corps was advancing in the coastal Arakan Province, while the British IV Corps had pushed two Indian infantry divisions almost to the Chindwin River at Tamu and Tiddim. These two divisions were widely separated and vulnerable to being isolated.
The Japanese planned that a division from the Twenty-Eighth Army would launch a diversionary attack in the Arakan, codenamed Ha Go, in the first week of February. This would attract Allied reserves from Assam, and also create the impression that the Japanese intended to attack Bengal through Chittagong.
In the centre, Mutaguchi's Fifteenth Army would launch the main attack into Manipur in the first week in March, aiming to capture Imphal and Kohima, scattering British forces and forestalling any offensive movements against Burma.In detail, the Fifteenth Army plans were:
At the insistence of Bose, two brigades from the Indian National Army were also assigned to the attacks on Imphal from the south and east. The Japanese had originally intended using the INA as auxiliaries to their forces only, for reconnaissance and propaganda.
The staff at Burma Area Army had originally thought this plan too risky. They believed it was unwise to separate the attacking forces so widely, but several officers who were vocal in their opposition were transferred.Mutaguchi's divisional commanders were also pessimistic. They thought that Mutaguchi was gambling too heavily on gaining early success to solve supply problems. Some of them thought him a "blockhead", or reckless.
In early 1944, the Allied formations in Assam and Arakan were part of the British Fourteenth Army, commanded by Lieutenant General William Slim. Over the preceding year, since the failure of an earlier offensive in the Arakan, he and his predecessor, General George Giffard, had been striving to improve the health, training and morale of the British and Indian units of the army. Through improvements in the lines of communication, better administration in the rear areas, and above all, better supply of fresh rations and medicines, these efforts had been successful. The Allies had also developed methods to counter the standard Japanese tactics of outflanking and isolating formations. In particular, they would increasingly depend upon aircraft to supply cut-off units. The Japanese had not anticipated this, and their attacks would be thwarted several times.
From various intelligence sources, Slim and Lieutenant General Geoffry Scoones (commanding Indian IV Corps) had learned of the general intentions of the Japanese to launch an offensive, although they did not have specific information on the Japanese objectives and were to be surprised several times when the Japanese did launch their attacks. Rather than anticipate the Japanese by attacking across the Chindwin, or trying to defend the line of the river itself, Slim intended to exploit the known Japanese logistical weaknesses by withdrawing into Imphal to fight a defensive battle where the Japanese would be unable to supply their troops.
The diversionary Japanese attack in Arakan began on 5 February. A force from the Japanese 55th Division infiltrated the lines of Indian XV Corps to overrun an Indian divisional headquarters and isolate the Corps' forward divisions. When they tried to press their attacks against a hastily fortified administrative area known as the "Admin Box", they found that Allied aircraft dropped supplies to the garrison, while the Japanese themselves were cut off from their supply sources and starved. British and Indian tanks and infantry broke through a hill pass to relieve the defenders of the Box. The badly supplied and starving Japanese forces were forced to withdraw.
The main U Go offensive began on 6 March 1944. Slim and Scoones had given their forward divisions orders to withdraw too late. The 20th Indian Division withdrew safely, but the 17th Indian Division was cut off and forced to fight its way back into the Imphal plain. Scoones was forced to commit almost all his reserves to help the 17th Division. Because the diversionary offensive in the Arakan had already failed, the Allies were able to fly a division (including its artillery and front-line transport) from the Arakan front to Imphal, in time to prevent the Japanese 15th Division overrunning Imphal from the north.
During April, the Japanese attacks against the defences at the edge of the Imphal plain were all held. In May, IV Corps began a counter-offensive, pushing northward to link up with a relieving force fighting its way southward from Kohima. Although the Allied progress was slow, the Japanese 15th Division was forced to withdraw through lack of supply, and the Allies reopened the Kohima-Imphal road on 22 June, ending the siege (although the Japanese continued to mount attacks from the south and east of Imphal).
The battle of Kohima took place in two stages. From 3 to 16 April 1944, the Japanese 31st Division attempted to capture Kohima ridge, a feature which dominated the road from Dimapur to Imphal on which IV Corps at Imphal depended for supply. On 16 April the small British force at Kohima was relieved, and from 18 April to 16 May the newly arrived Indian XXXIII Corps counter-attacked to drive the Japanese from the positions they had captured. At this point, with the Japanese starving, Lieutenant General Kōtoku Satō ordered his division to withdraw. Although a detachment continued to fight rearguard actions to block the road, XXXIII Corps drove south to link up with the defenders of Imphal on 22 June.
Mutaguchi continued to order fresh attacks, but by late June it was clear that the starving and disease-ridden Japanese formations were in no state to obey. When he realised that none of his formations were obeying his orders for a renewed attack, Mutaguchi finally ordered the offensive to be broken off on 3 July. The Japanese, reduced in many cases to a rabble, fell back to the Chindwin, abandoning their artillery, transport, and soldiers too sick to walk.
The Japanese defeats at Kohima and Imphal were the largest up until that time. The British and Indian forces had lost around 16,987 men, dead, missing and wounded.The Japanese suffered 60,643 casualties, including 13,376 dead. Most of these losses were the result of starvation, disease and exhaustion.
The defeat resulted in sweeping changes in command within the Japanese Army in Burma. Mutaguchi sacked all his division commanders during the operation, before being sacked himself on 30 August. Kawabe, whose health was broken, was also dismissed. Many of the senior staff officers at the headquarters of Fifteenth Army and Burma Area Army were also transferred to divisional or regimental commands.
Field Marshal William Joseph Slim, 1st Viscount Slim,, usually known as Bill Slim, was a British military commander and the 13th Governor-General of Australia.
The British Fourteenth Army was a multi-national force comprising units from Commonwealth countries during World War II. Many of its units were from the Indian Army as well as British units and there were also significant contributions from West and East African divisions within the British Army. It was often referred to as the "Forgotten Army" because its operations in the Burma Campaign were overlooked by the contemporary press, and remained more obscure than those of the corresponding formations in Europe for long after the war. For most of the Army's existence, it was commanded by Lieutenant-General William Slim.
The Burma campaign was a series of battles fought in the British colony of Burma. It was part of the South-East Asian theatre of World War II and primarily involved forces of the Allies; the British Empire and the Republic of China, with support from the United States. They faced against the invading forces of Imperial Japan, who were supported by the Thai Phayap Army, as well as two collaborationist independence movements and armies, the first being the Burma Independence Army, which spearheaded the initial attacks against the country. Puppet states were established in the conquered areas and territories were annexed, while the international Allied force in British India launched several failed offensives. During the later 1944 offensive into India and subsequent Allied recapture of Burma the Indian National Army, led by revolutionary Subhas C. Bose and his "Free India", were also fighting together with Japan. British Empire forces peaked at around 1,000,000 land and air forces, and were drawn primarily from British India, with British Army forces, 100,000 East and West African colonial troops, and smaller numbers of land and air forces from several other Dominions and Colonies.
The Battle of Kohima was the turning point of the Japanese U Go offensive into India in 1944 during the Second World War. The battle was fought in three stages from 4 April to 22 June 1944 around the town of Kohima, the capital of Nagaland in northeast India. From 3 to 16 April, the Japanese attempted to capture Kohima ridge, a feature which dominated the road by which the besieged British and Indian troops of IV Corps at Imphal were supplied. By mid-April, the small British and Indian force at Kohima was relieved.
The Battle of Imphal took place in the region around the city of Imphal, the capital of the state of Manipur in northeast India from March until July 1944. Japanese armies attempted to destroy the Allied forces at Imphal and invade India, but were driven back into Burma with heavy losses. Together with the simultaneous Battle of Kohima on the road by which the encircled Allied forces at Imphal were relieved, the battle was the turning point of the Burma campaign, part of the South-East Asian Theatre of the Second World War. The Japanese defeat at Kohima and Imphal was the largest up until that time, with many of the Japanese deaths resulting from starvation, disease and exhaustion suffered during their retreat.
The Battle of the Admin Box took place on the southern front of the Burma Campaign from 5 to 23 February 1944, in the South-East Asian Theatre of World War II.
Kōtoku Satō was a lieutenant general in the Imperial Japanese Army in World War II.
The 36th Indian Infantry Division was an infantry division of the Indian Army during World War II. The division was subsequently redesignated as a British Army formation, the 36th Infantry Division in September 1944. It served in India and during the Burma Campaign. After the end of the war it was disbanded and its remaining British units were transferred to the British 2nd Infantry Division.
The concurrent Battle of Meiktila and Battle of Mandalay were decisive engagements near the end of the Burma Campaign. Collectively, they are sometimes referred to as the Battle of Central Burma. Despite logistical difficulties, the Allies were able to deploy large armoured and mechanised forces in Central Burma, and also possessed air supremacy. Most of the Japanese forces in Burma were destroyed during the battles, allowing the Allies to later recapture the capital, Rangoon, and reoccupy most of the country with little organised opposition.
The 15th Division was an infantry division in the Imperial Japanese Army. Its tsūshōgō code name was the Festival Division, and its military symbol was 15D. The 15th Division was one of four new infantry divisions raised by the Imperial Japanese Army in the closing stages of the Russo-Japanese War (1904–1905). With Japan's limited resources towards the end of that conflict, the entire IJA was committed to combat in Manchuria, leaving not a single division to guard the Japanese home islands from attack. The 15th Division was initially raised from men in the area surrounding Nagoya under the command of Lieutenant General Okihara Kofu.
Ren'ya Mutaguchi was a Japanese military officer, lieutenant general in the Imperial Japanese Army during World War II and field commander of the IJA forces during the Battle of Imphal.
The 33rd Division was an infantry division of the Imperial Japanese Army. Its call sign was the Bow Division. The 33rd Division was raised in Utsunomiya, Tochigi prefecture, simultaneously with 32nd, 34th, 35th, 36th and 37th Divisions. Its headquarters were initially in Sendai. It was raised from conscripts largely from the northern Kantō prefectures of Tochigi, Ibaraki and Gunma.
The 31st Division was an infantry division of the Imperial Japanese Army. Its call sign was the Furious Division. The 31st Division was raised during World War II in Bangkok, Thailand, on March 22, 1943, out of Kawaguchi Detachment and parts of the 13th, 40th and 116th divisions. The 31st division was initially assigned to 15th army.
The Battles and Operations involving the Indian National Army during World War II were all fought in the South-East Asian theatre. These range from the earliest deployments of the INA's preceding units in espionage during Malayan Campaign in 1942, through the more substantial commitments during the Japanese Ha Go and U Go offensives in the Upper Burma and Manipur region, to the defensive battles during the Allied Burma Campaign. The INA's brother unit in Europe, the Indische Legion did not see any substantial deployment although some were engaged in Atlantic wall duties, special operations in Persia and Afghanistan, and later a small deployment in Italy. The INA was not considered a significant military threat. However, it was deemed a significant strategic threat especially to the Indian Army, with Wavell describing it as a target of prime importance.
The Burma campaign in the South-East Asian Theatre of World War II took place over four years from 1942 to 1945. During the first year of the campaign, the Imperial Japanese Army with aid from Burmese insurgents had driven British forces and Chinese forces out of Burma, and occupied most of the country. From May to December 1942, most active campaigning ceased as the monsoon rains made tactical movement almost impossible in the forested and mountainous border between India and Burma, and both the Allies and Japanese faced severe logistical constraints.
The fighting in the Burma campaign in 1944 was among the most severe in the South-East Asian Theatre of World War II. It took place along the borders between Burma and India, and Burma and China, and involved the British Commonwealth, Chinese and United States forces, against the forces of Imperial Japan and the Indian National Army. British Commonwealth land forces were drawn primarily from the United Kingdom, British India and Africa.
The Japanese 15th Army was an army of the Imperial Japanese Army during World War II. It was involved in the invasion of Burma in December 1941 and served in that country for most of its war service.
The Battle of Sangshak took place in Manipur in the forested and mountainous frontier area between India and Burma, from 20 March to 26 March 1944. The Japanese drove a parachute brigade of the British Indian Army from its positions with heavy casualties, but suffered heavy casualties themselves. The delay imposed on the Japanese by the battle allowed British and Indian reinforcements to reach the vital position at Kohima before the Japanese.
The Arakan Campaign of 1942–43 was the first tentative Allied attack into Burma, following the Japanese conquest of Burma earlier in 1942, during the Second World War. The British Army and British Indian Army were not ready for offensive actions in the difficult terrain they encountered, nor had the civil government, industry and transport infrastructure of Eastern India been organised to support the Army on the frontier with Burma. Japanese defenders occupying well-prepared positions repeatedly repulsed the British and Indian forces, who were then forced to retreat when the Japanese received reinforcements and counter-attacked.
The British Indian XXXIII Corps was a corps-sized formation of the Indian Army during World War II. It was disbanded and the headquarters was recreated as an Army headquarters in 1945.