Operation U-Go

• 1. Origins Of The Plan

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  In 1942, the Japanese Army had driven British and Indian troops out of Burma. When monsoon rains stopped campaigning, British forces occupied Imphal, the capital of Manipur state. This plain lay astride one of the few practicable routes over jungle-covered mountains separating India and Burma. Lieutenant General Shōjirō Iida reported that a renewed advance would be unwise due to difficult terrain and supply problems. During the following year and a half, Allies reconstructed lines of communication to Assam in north-east India. The United States Army constructed several airbases in Assam with large numbers of Indian labourers. Supplies were flown to the Nationalist Chinese government under Chiang Kai-shek via an air route known as the Hump. Americans also began constructing the Ledo Road, a land link from Assam to China. In mid-1943, Japanese command in Burma was reorganised. General Iida returned to Japan while a new headquarters called Burma Area Army formed under Lieutenant-General Masakasu Kawabe. One subordinate formation responsible for the central front facing Imphal and Assam became the Fifteenth Army. Its new commander was Lieutenant-General Renya Mutaguchi.

• 2. Political Alliances And Influence

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  Mutaguchi and Prime Minister Hideki Tōjō found influence from Subhas Chandra Bose who led Azad Hind. This movement dedicated itself to freeing India from British rule. Bose served as commander-in-chief of Azad Hind Fauj or Indian National Army. The INA consisted mainly of former prisoners-of-war captured by Japan after Singapore fell. It also included Indian expatriates in South East Asia joining the nationalist movement. Bose persuaded several Japanese that victory would lead to collapse of British rule in India. Their western boundary controlled by a friendly government appeared attractive to Japanese planners. This aligned with ideas that Japanese expansion supported Asian governments countering western colonialism. Syonan Sinbun published the 26th of January 1943 noted these political dimensions. Lebra's 1977 work documented page 20 regarding these influences. At Bose's insistence, two brigades from the Indian National Army joined attacks on Imphal from south and east. Originally Japanese intended using INA only as auxiliaries for reconnaissance and propaganda purposes.

• 3. Logistical Preparations And Intelligence

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  Allied formations in Assam and Arakan formed part of British Fourteenth Army commanded by Lieutenant General William Slim. Over preceding year since failure of earlier offensive in Arakan, Slim improved health training and morale of units. Through better lines of communication and administration in rear areas, efforts succeeded. Fresh rations and medicines supplied troops effectively. Allies developed methods countering standard Japanese tactics of outflanking and isolating formations. Aircraft increasingly supplied cut-off units while Japanese had not anticipated this development. From various intelligence sources, Slim and Lieutenant General Geoffry Scoones learned general intentions of Japanese offensive launch. They lacked specific information on objectives yet remained surprised when attacks began. Rather than attacking across Chindwin or defending river line itself, Slim planned exploiting known Japanese logistical weaknesses. He withdrew into Imphal to fight defensive battle where Japanese could not supply their troops. Allen's 1984 publication details page 155 regarding these strategic decisions. The Hump air route crossed several mountain ranges delivering critical supplies throughout campaign period.

• 4. The Arakan Diversionary Attack

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  Diversionary Japanese attack in Arakan began on the 5th of February 1944. A force from Japanese 55th Division infiltrated Indian XV Corps lines overrunning divisional headquarters. They isolated Corps forward divisions attempting to press attacks against hastily fortified administrative area called Admin Box. Allied aircraft dropped supplies to garrison while Japanese themselves became cut off from supply sources and starved. British and Indian tanks plus infantry broke through hill pass relieving defenders of the Box. Badly supplied and starving Japanese forces forced withdrawal. Ha Go operation failed completely drawing away reserves from main front as intended. This failure left Allies free to fly entire division including artillery and transport from Arakan to Imphal. Timing prevented Japanese 15th Division from overrunning Imphal from north direction during critical early phase.

• 5. Battles For Imphal And Kohima

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  Main U Go offensive began on the 6th of March 1944 when Slim and Scoones gave forward divisions orders too late. Twenty-First Indian Division withdrew safely but Seventeenth Indian Division got cut off fighting way back into Imphal plain. Scoones committed almost all reserves helping Seventeenth Division recover position. During April, Japanese attacks against defences at edge of Imphal plain held firm. In May IV Corps began counter-offensive pushing northward linking up with relieving force southward from Kohima. Although progress slow, Japanese Fifteenth Division forced withdraw due lack of supply. Allies reopened Kohima, Imphal road on the 22nd of June ending siege though Japanese continued mounting attacks from south and east. Battle of Kohima took place in two stages from 3 to the 16th of April 1944. Thirty-first Division attempted capture Kohima ridge dominating road from Dimapur to Imphal. On the 16th of April small British force relieved while newly arrived Indian XXXIII Corps counter-attacked driving Japanese from captured positions. At end of May starving Lieutenant General Kōtoku Satō defied Mutaguchi ordering division withdrawal despite rearguard actions continuing.

• 6. Human Cost And Retreat

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  Mutaguchi ordered fresh attacks until late June when starving disease-ridden formations proved unable obey commands. Realising none his formations obeyed renewed attack orders, Mutaguchi finally broke offensive on the 3rd of July. Japanese reduced many cases to rabble fell back across Chindwin River abandoning artillery transport sick soldiers. Most losses resulted from starvation disease exhaustion rather than direct combat casualties. Japanese suffered 60,643 casualties including 13,376 dead during entire operation period. British and Indian forces lost around 16,987 men dead missing wounded combined total. These figures represented largest defeats up until that time for either side in Burma Campaign. The retreat left behind vast quantities equipment supplies abandoned along mountain trails leading toward home bases.

• 7. Command Changes And Legacy

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  Japanese defeats at Kohima and Imphal triggered sweeping changes command within Japanese Army in Burma region. Mutaguchi sacked all division commanders during operation before being dismissed himself on the 30th of August. Kawabe whose health broken also removed from position. Many senior staff officers Fifteenth Army headquarters transferred to divisional regimental commands instead of remaining at higher levels. Allen's 1984 publication page 386 documents these personnel shifts following catastrophic failure. Neither Lieutenant General Kawabe nor Field Marshal Hisaichi Terauchi given opportunity call off attack once launched. Prime Minister Hideki Tōjō gave final sanction after questioning staff officer over aspects plan from his bath. This decision marked turning point where neither subordinate commanders nor field marshals exercised control over offensive execution. Long-term impact reshaped Burma Campaign strategy moving focus away from large-scale offensives toward defensive postures.