Battle of Imphal
In March 1943, Lieutenant-General Renya Mutaguchi took command of the Fifteenth Army in Burma. He immediately began pushing for an invasion of India with a forcefulness that unsettled his superiors. His motives remain unclear to historians, but he believed it was his destiny to win the decisive battle for Japan. This belief grew from years of victories since the Marco Polo Bridge incident in 1937. Some staff members thought he had been goaded by the first Chindit expedition launched by Orde Wingate early in 1943. The Allies publicized the success of that raid while hiding their own losses to disease and exhaustion. This selective reporting may have led Mutaguchi to underestimate the difficulties ahead.
By early 1944, the war was turning against Japan on multiple fronts. Allied submarines attacked merchant ships across the Pacific, and American forces pushed back Japanese lines in the southwest. In Southeast Asia, the situation remained tense as the Allies prepared offensives from India and Yunnan into Burma. Imphal, located in Manipur near the Burmese border, had become a major logistical hub. It contained airfields, encampments, and supply dumps linked to Dimapur by a winding road through the Naga Hills.
Mutaguchi named his plan Operation U-Go or Operation C. He intended to cut Allied communication lines to northern Burma where American-led forces built the Ledo Road. He also aimed to threaten airfields supplying Nationalist Chinese leader Chiang Kai-shek via an airlift over the Himalayas known as The Hump. Despite reservations from commanders at Burma Area Army and Southern Expeditionary Army Group, Mutaguchi persisted. Prime Minister Hideki Tojo and Imperial General Headquarters eventually approved the operation.
The plan relied on four main divisions attacking from different directions. The 33rd Infantry Division under Lieutenant-General Motoso Yanagida would approach from the south. Yamamoto Force, supported by sixty-six tanks under Lieutenant Colonel Nobuo Ueda, would attack from the east. The 15th Infantry Division would envelop Imphal from the north while still arriving from Thailand. A separate subsidiary operation involved the 31st Infantry Division under Lieutenant-General Kotoku Sato capturing Kohima to isolate Imphal completely.
Subhas Chandra Bose insisted that the Indian National Army contribute substantially to the campaign. Originally intended only for reconnaissance and propaganda, they became active participants. Units of the First Division covered the left flank of the advancing 33rd Division. Later in the battle, the 2nd Guerrilla Regiment attached itself to Yamamoto Force. The Special Services Group acted as scouts and pathfinders during the opening stages. They infiltrated British lines hoping to encourage defections among British Indian Army units.
Mutaguchi's divisional commanders disagreed with his strategy. Sato distrusted his motives while Yanagida openly called him a blockhead. Yamauchi was already ill and fatalistic about the outcome. Their primary concern was supply. Mutaguchi assumed victory within three weeks but knew supplies beyond that period depended on capturing Allied dumps before monsoon rains made routes impassable. He proposed using Genghis Khan rations consisting of herds of buffalo and cattle driven across the Chindwin River. Most animals died from lack of forage or rotted before reaching troops.
Lieutenant General William Slim commanded the Fourteenth Army defending the region around Imphal. His IV Corps under Lieutenant General Geoffry Scoones had been thrown forward almost to the Chindwin River. This positioning left them widely separated and vulnerable to isolation. The 20th Indian Infantry Division under Major-General Douglas Gracey held Tamu southeast of Imphal. Though untried, this division remained well-trained. The 17th Indian Infantry Division under Major-General Punch Cowan occupied Tiddim south of Imphal at the end of a long communication line. It had fought intermittently since December 1941.
The 23rd Indian Infantry Division under Major-General Ouvry Roberts served as reserve forces in and around Imphal. Despite two years of service on the front, it suffered severe understrength conditions due to endemic diseases like malaria and typhus. The 50th Indian Parachute Brigade under Brigadier Maxwell Hope-Thompson conducted advanced jungle training north of Imphal. The 254th Indian Tank Brigade stationed Stuart light tanks and M3 Lee tanks within the city limits.
Indian divisions combined British and Indian personnel. Each brigade typically included one British battalion, one Gurkha battalion, and one Indian battalion. Two brigades consisted entirely of Gurkha units: the 37th Brigade in the 23rd Division and the 63rd Brigade in the 17th Division. Field artillery regiments usually belonged to British units while mountain artillery regiments were Indian. This mixed composition created complex command structures during the fighting.
In late February, Japanese launched a counterattack against Indian XV Corps in Arakan using tactics similar to those Mutaguchi planned for Imphal. Allies called this engagement the Battle of the Admin Box because it involved supply areas for brigades of the 7th Division. Allied aircraft parachuted supplies to cut-off troops allowing them to stand firm while infiltrating Japanese ran out of food. From that point forward, Allies relied increasingly on transport aircraft. They also unexpectedly encountered tanks which lightly equipped infiltrators could not counter effectively.
Even as Japanese prepared their attack, Allies launched Operation Thursday on the 5th of March 1944. This airborne phase of the second Chindit expedition forced Japanese officers like Major-General Noburo Tazoe to urge diversion of offensive troops to secure rear areas. Mutaguchi dismissed these concerns claiming he would occupy air bases within weeks. When intelligence indicated a major Japanese offensive was impending, Slim and Scoones planned to withdraw forward divisions into the Imphal plain forcing Japanese to fight at the end of impossibly long lines of communication.
Japanese troops began crossing the Chindwin River on the 8th of March 1944. Scoones ordered his forward divisions to withdraw only on March 13. The 20th Indian Division held Tamu near the Chindwin where Moreh contained a large supply dump. On March 20 six Lee medium tanks from the 3rd Carabiniers clashed with six Type 95 Ha-Go tanks leading Yamamoto's advance. Lighter Japanese tanks were destroyed in the engagement. Acting major-general Douglas Gracey opposed retreat but was ordered on March 25 to detach part of his division providing reserve for IV Corps.
This left the division too weak to hold Tamu and Moreh so they withdrew to Shenam Saddle. A complex of hills through which the Imphal-Tamu road ran became their new position. The supply dump at Moreh burned while two hundred cattle there were slaughtered. The division fell back without difficulty because two battalions from the Japanese 15th Division remained delayed at Indaw by Chindits unable to intervene.
Further south, the 17th Indian Division faced pressure from the Japanese 33rd Division. Patrols warned Cowan of advancing Japanese forces as early as March 8 allowing him to regroup protection for his rear. On March 13 the Japanese 215th Regiment attacked a supply dump at milestone 109 twenty miles behind Cowan's leading outposts. Simultaneously the 214th Regiment seized Tongzang and Tuitum Saddle across the road a few miles behind main positions. The Indian division began withdrawing on March 14.
At Tuitum Saddle the Japanese 214th Regiment failed to dig in properly before being attacked by the 48th Indian Infantry Brigade on March 15. Heavy casualties forced them away from the road. Further north Japanese captured the depot at Milestone 109 on March 18 but Indian troops recovered it on March 25. Cowan secured the bridge over the Manipur River which became the most vulnerable point in his division's rear. The rearguard crossed safely on March 26 demolishing the bridge behind them.
Both sides suffered heavy casualties during these early clashes. Yanagida grew pessimistic after receiving garbled radio messages suggesting one regiment destroyed at Tongzang. He advanced cautiously despite reprimands from Mutaguchi. Scoones sent the bulk of his only reserve the 23rd Indian Infantry Division to aid the 17th Division. These two divisions reached Imphal plain on April 4 supplied by parachute drops from Allied aircraft.
By mid-1944 Allied air forces enjoyed undisputed air supremacy over Burma. The last major effort by the Japanese Army Air Force occurred over Arakan in February and March when they suffered severe losses. During the Imphal and Kohima battles they made barely half a dozen significant raids. IV Corps received close air support from fighter-bombers and dive bombers of 221 Group of the RAF. Allied fighters shot up enemy concentrations supply dumps transport roads and bridges all the way to the Chindwin river.
The monsoon season running from May to September did not diminish activity. The RAF Third Tactical Air Force flew twenty-four thousand sorties during the worst four months nearly six times the previous year's record. Most important contribution came from British and American transport aircraft flying men equipment and supplies into airstrips at Imphal and Palel until onset of monsoon rains. Although cut off by land the town maintained a lifeline through constant aerial delivery.
Allied air forces transported nineteen thousand tons of supplies and twelve thousand men into Kohima and Imphal while evacuating thirteen thousand casualties and forty-three thousand non-combatants. They delivered over one million gallons of fuel more than one thousand bags of mail and forty million cigarettes. Several thousand mules supplied outlying outposts so animal fodder also flown in during siege. Aircraft parachuted ammunition rations and drinking water to surrounded units.
At start of battle South East Asia Command possessed seventy-six transport aircraft mainly C-47 Skytrain available but many others dedicated to supplying Nationalist Chinese under Chiang Kai-Shek or establishing USAAF bomber bases via The Hump. Admiral Louis Mountbatten Commander-in-Chief lacked authority to commandeer these aircraft yet at crisis point mid-March he acquired twenty C-46 Commando aircraft equivalent to another thirty C-47s supported by American officers at SEAC and China-Burma-India Theater headquarters.
The Special Services Group redesignated Bahadur Group acted as scouts and pathfinders with advanced Japanese units opening stages offensive. They infiltrated through British lines encouraging defections among British Indian Army soldiers. During early part of offensive Bahadur Group apparently achieved some success inducing desertions from Commonwealth ranks.
On Japanese left flank INA's Subhas Brigade led by Shah Nawaz Khan reached edge of Chin Hills below Tiddim and Fort White end March. From this position second Battalion sent companies relieving Japanese forces at Falam and Hakha where Khan's forces sent out patrols laying ambushes for Chin guerrillas under Lieutenant-Colonel Oates taking prisoners. Middle May force under Mahboob Boobie Ahmed attacked captured hilltop fortress Klang Klang.
Third Battalion moved to Fort White-Tongzang area premature anticipation destruction Major General Frank Messervy's 7th Indian Infantry Division Arakan allowing it receive volunteers. Towards end May INA's 1st and 2nd Guerrilla Regiments redirected Kohima moving north across Japanese rear but reaching Ukhrul when Japanese began withdrawal decided attack Imphal instead both units suffered some desertions scale not expected by Commonwealth forces.
By May all Japanese attacks halted leaving them starving and exhausted. Neither 31st Division fighting Kohima nor 15th Division received adequate supplies since offensive began. Lieutenant General Sato commander 31st Division ordered retreat end May finding food allowed Indian XXXIII Corps drive Japanese from Kohima advancing south. Troops forced abandon defensive positions scavenging local villages or lines
communication.
Mutaguchi dismissed mortally ill Yamauchi replacing him with Lieutenant General Nobuo Tanaka but changes did nothing. After driving rearguards Miyazaki Group independent detachment 31st Division and 60th Regiment delaying positions Dimapur-Imphal road leading troops IV Corps XXXIII Corps met Milestone 109 north Imphal June 22 raising siege completely.
Japanese realized operation ought broken off early May Vice-Chief General Staff Hikosaburo Hata toured inspection Southern Army headquarters late April returning Tokyo reporting pessimistically outcome large staff meeting Prime Minister Hideki Tojo dismissing concerns source junior staff officer Major Masaru Ushiro Burma Area Army HQ Messages sent Imperial Headquarters urging fought end.
Kawabe traveled north Rangoon seeing situation himself May 25 officers interviewed expressed confidence success if reinforcements provided concealing losses seriousness situation meeting Mutaguchi Kawabe June 6 used haragei unspoken form communication gesture expression tone voice conveying conviction success impossible neither wished bear responsibility ordering retreat Kawabe subsequently became ill dysentery perhaps physically unfit duty nevertheless ordered repeated attacks stating later Bose key Japan India future.
The Japanese defeat at Kohima and Imphal represented largest casualties up until that time totaling fifty-four thousand eight hundred seventy-nine including thirteen thousand three hundred seventy-six dead plus nine hundred twenty preliminary battles Assam. Most losses resulted from starvation disease exhaustion suffered during retreat. Allies suffered twelve thousand six hundred three casualties overall.
After war Commonwealth War
Graves Commission established Imphal War Cemetery Kohima War Cemetery commemorating British Indian soldiers died Second World War. In December Slim three corps commanders Scoones Christison Stopford knighted viceroy Lord Wavell ceremony Imphal front Scottish Gurkha Punjab regiments. Slim created KCB others made KBEs voting contest run British National Army Museum battles Imphal Kohima jointly bestowed Britain's Greatest Battle 2013.
Japanese lost almost every one twelve thousand pack horses mules transport units thirty thousand cattle beasts burden rations many trucks vehicles loss pack animals crippled several divisions following year Mutaguchi sacked division commanders battle both himself Kawabe subsequently relieved command. Air operations continued throughout worst four months monsoon RAF Third Tactical Air Force flew twenty-four thousand sorties nearly six times previous year record proving air superiority decisive factor victory.
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Common questions
Who commanded the Japanese Fifteenth Army during the Battle of Imphal?
Lieutenant-General Renya Mutaguchi took command of the Fifteenth Army in Burma in March 1943. He initiated Operation U-Go to invade India despite reservations from his superiors and staff members.
When did Japanese troops begin crossing the Chindwin River for the attack on Imphal?
Japanese troops began crossing the Chindwin River on the 8th of March 1944. This marked the start of the offensive that would lead to the siege of Imphal and Kohima.
What was the total number of casualties suffered by the Japanese forces at Imphal and Kohima?
The Japanese defeat resulted in fifty-four thousand eight hundred seventy-nine casualties including thirteen thousand three hundred seventy-six dead. Most losses occurred due to starvation disease and exhaustion during the retreat rather than direct combat.
How many transport aircraft were available to SEAC at the start of the battle?
South East Asia Command possessed seventy-six transport aircraft mainly C-47 Skytrain when the battle started. Admiral Louis Mountbatten later acquired twenty additional C-46 Commando aircraft to support operations.
Which Indian divisions defended the region around Imphal under Lieutenant General William Slim?
Lieutenant General William Slim commanded the Fourteenth Army which included the 20th Indian Infantry Division held Tamu and the 17th Indian Infantry Division occupying Tiddim. The 23rd Indian Infantry Division served as reserve forces within and around Imphal itself.