Battle of Imphal

• 1. Introduction

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  The Battle of Imphal began in March 1944 with a Japanese army crossing the Chindwin River, convinced it could destroy the Allied forces in northeast India and reshape the entire war. The city of Imphal, capital of Manipur, sat at the heart of it all: a sprawling logistic base of airfields, supply dumps and encampments, connected to the outside world by a single road winding 100 miles through the steep Naga Hills. The man who ordered the attack, Lieutenant-General Renya Mutaguchi, believed this battle was his destiny. He had calculated that success would come within three weeks, after which his troops would live off captured Allied supplies. He was wrong on almost every count.

  What unfolded over the following months was one of the largest defeats in Japanese military history. The questions worth asking are not just how the Allies held on, but why Japanese commanders pressed forward long after the outcome was clear, and what the airlift that kept Imphal alive tells us about how modern warfare is actually won.

• 2. The Man Behind the Offensive

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  Renya Mutaguchi took command of the Fifteenth Army in March 1943, and from that first day he pushed for an invasion of India. His confidence drew from personal history: he had played a central role in Japanese victories stretching back to the Marco Polo Bridge incident of 1937. He had watched the British in Malaya and Singapore and in Burma in 1942, and what he saw was poorly trained, poorly led troops. He concluded, as a fixed belief rather than a working hypothesis, that British and Indian soldiers were inherently inferior.

  Mutaguchi may also have been stung by the first Chindit expedition, the British raid behind Japanese lines launched by Orde Wingate early in 1943. The Allies publicised the successful aspects of that raid while concealing their casualties from disease and exhaustion. That gap between perception and reality likely led Mutaguchi and his staff to underestimate the ordeal ahead of them.

  His plan, named U-Go or Operation C, required three divisions to converge on Imphal from different directions, while a fourth isolated it by seizing Kohima to the north. Mutaguchi assumed his troops would capture Allied supply dumps within three weeks, before the monsoon rains made the supply routes from the Chindwin impassable. Every one of his divisional commanders disagreed with the plan to some degree. General Yanagida openly called Mutaguchi a blockhead. General Sato distrusted his motives. General Yamauchi was already gravely ill. Their shared worry was supply, and they were right to worry.

• 3. Opening Moves

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  Japanese troops began crossing the Chindwin River on the 8th of March. Allied commanders Slim and Scoones had planned to withdraw their forward divisions into the Imphal plain and let the Japanese exhaust themselves at the end of long supply lines. They misjudged the timing and the scale of the attack, however, and Scoones did not issue withdrawal orders until the 13th of March, five days after the crossing began.

  In the south, the 17th Indian Infantry Division under Major-General Cowan had already received warning from patrols on the 8th of March about a Japanese force moving against its rear. That early intelligence allowed Cowan to regroup his division before the Japanese 215th Regiment struck a supply dump at milestone 109, twenty miles behind the Indian forward positions, on the 13th of March. The Japanese 214th Regiment seized Tongzang and a ridge called Tuitum Saddle the same day. When the Indian division attacked Tuitum Saddle on the 15th of March, the Japanese regiment had not yet dug in properly and suffered heavy casualties, clearing the road. The 17th Division's rearguard crossed the bridge over the Manipur River safely on the 26th of March and then demolished it.

  In the east, a clash on the 20th of March between six Lee medium tanks of the 3rd Carabiniers and six Japanese Type 95 Ha-Go tanks leading Yamamoto Force's advance ended quickly. The lighter Japanese tanks were destroyed. The Japanese had assumed tanks could not operate on the steep jungle hills around Imphal. That assumption would cost them repeatedly.

• 4. The Siege Takes Shape

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  By the beginning of April, Japanese forces were pressing the Imphal plain from multiple directions. In the north, the Japanese 15th Division's 60th Regiment captured a British supply dump at Kanglatongbi, only to find it had already been emptied of food and ammunition. A battalion of the 51st Regiment, commanded by Colonel Kimio Omoto, seized Nungshigum Ridge, which overlooked the main airstrip at Imphal. That ridge was a direct threat to IV Corps, and on the 13th of April the 5th Indian Division counter-attacked with air strikes, massed artillery and M3 Lee tanks from B Squadron of the 3rd Carabiniers.

  The Japanese regiment holding the ridge had almost no effective anti-tank weapons. The tank assault up gradients Lee tanks had never before attempted in action proved decisive. The Japanese were driven from the ridge with heavy losses. Every officer of the Carabiniers and of the attacking infantry battalion, the 1st Battalion of the 17th Dogra Regiment, was killed or wounded.

  In the south, around the village of Bishenpur, the Japanese 33rd Division cut a secondary track from Silchar into the plain and pushed toward Imphal through the western hills. Their leading troops were halted by British artillery fire only 10 miles from Imphal, stopped not by a counterattack but by their own lack of supplies. At the Shenam Saddle to the east, Yamamoto Force fought for five peaks commanding the road from the 8th to the 22nd of April, seizing some, losing others to Indian and British counterattacks. On the 28th of April, the INA's Gandhi Brigade, two battalions led by Inayat Kiyani, attacked Palel airfield but withdrew after failing to rendezvous with Japanese units. The brigade had brought forward only one day's supplies and suffered 250 casualties to shellfire after pulling back.

• 5. Keeping Imphal Alive

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  South East Asia Command began the battle with 76 transport aircraft, mainly C-47 Skytrains, available for the Imphal front. Many others were dedicated to supplying Nationalist Chinese forces under Chiang Kai-shek or to building American bomber bases in China via the route over the Himalayas known as the Hump. Admiral Louis Mountbatten, the Commander-in-Chief, technically lacked the authority to redirect those aircraft, but at the crisis point in mid-March he did so anyway, acquiring 20 C-46 Commando aircraft equivalent in capacity to roughly 30 C-47s.

  The airlift sustained Imphal through the entire siege. By the battle's end, Allied aircraft had delivered 19,000 tons of supplies and 12,000 men into Kohima and Imphal combined, and had flown out 13,000 casualties and 43,000 non-combatants. They carried over a million gallons of fuel, more than 1,000 bags of mail and 40 million cigarettes. Animal fodder for thousands of mules was flown in to supply outlying outposts. Surrounded units received parachute drops of ammunition, rations and drinking water.

  The Royal Air Force's Third Tactical Air Force flew 24,000 sorties during the worst four months of the monsoon season, nearly six times the previous year's record. Fighter-bombers and medium bombers attacked Japanese supply dumps, transport, roads and bridges all the way back to the Chindwin. The Japanese Army Air Force, having suffered severe losses over the Arakan in February and March, managed barely half a dozen significant raids over the entire Imphal-Kohima battle. The contrast between the two sides in the air was not merely an advantage; it was the structural difference between a force that could be resupplied and one that could not.

• 6. Collapse and Retreat

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  By late May the Japanese were past the point of coherent military action. Neither the 31st Division fighting at Kohima nor the 15th Division around Imphal had received adequate supplies since the offensive began. Lieutenant-General Sato, commanding the 31st Division, ordered a retreat at the end of May simply so his men could find food. That withdrawal allowed Indian XXXIII Corps to drive the Japanese from Kohima and advance south.

  In Tokyo, Lieutenant-General Hikosaburo Hata, the Vice-Chief of the General Staff, had toured Southern Army's headquarters in late April and reported pessimistically to Prime Minister Hideki Tojo. Tojo dismissed the concerns because Hata's source was Major Masaru Ushiro, a junior staff officer at Burma Area Army headquarters. Imperial Headquarters sent messages urging that the operation be fought to the end.

  General Kawabe travelled north from Rangoon on the 25th of May to see the situation himself. Officers he interviewed concealed their losses. At a meeting on the 6th of June, both Kawabe and Mutaguchi communicated through haragei, an unspoken language of gesture, expression and tone, that success was impossible. Neither would accept responsibility for ordering a retreat. Kawabe subsequently contracted dysentery. He kept ordering attacks.

  Mutaguchi finally broke off the offensive on the 3rd of July. His troops, reduced in many cases to a rabble, fell back to the Chindwin abandoning their artillery, transport and soldiers too sick or wounded to walk. When the Allies recovered Tamu at the end of July, they found 550 unburied Japanese corpses, with over 100 severely wounded soldiers dying among them.

  The Japanese suffered 54,879 casualties in total, including 13,376 dead, plus 920 casualties in the preliminary fighting in Assam. Most deaths came from starvation, disease and exhaustion during the retreat. Allied casualties reached 12,603. Mutaguchi had dismissed all of his divisional commanders during the battle. Both he and Kawabe were relieved of command in the aftermath. In December, Slim and three corps commanders were knighted by Viceroy Lord Wavell at a ceremony at Imphal, attended by Scottish, Gurkha and Punjab regiments.