The Battle of Imphal (Meitei: Japan Laan, lit. 'Japanese invasion'), also known as the "Stalingrad of the East" in combination with Kohima, 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 World War II. 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.
Situation
Background
In late 1941 and early 1942, the Imperial Japanese Army overran Burma, driving the British, Indian and Chinese defenders into India and Yunnan Province in China. They then held their lines against a limited attempt at a counter-offensive from December 1942 to February 1943.
In March 1943, the Japanese command in Burma had been reorganised. A new headquarters, Burma Area Army, was created under Lieutenant-General Masakazu Kawabe. One of its subordinate formations, responsible for the central part of the front facing Imphal and Assam, was the Fifteenth Army. Lieutenant-General Renya Mutaguchi was appointed to command this army in March 1943. From the moment he took command, Mutaguchi forcefully advocated an invasion of India. His motives for doing so are uncertain. He had played a major part in several Japanese victories, ever since the Marco Polo Bridge incident in 1937, and believed it was his destiny to win the decisive battle of the war for Japan. He may also have been goaded by the first Chindit expedition, a raid behind Japanese lines launched by the British under Orde Wingate early in 1943. The Allies had widely publicised the successful aspects of Wingate's expedition while concealing their losses to disease and exhaustion, possibly leading Mutaguchi and some of his staff to underestimate the difficulties they would later face.
At the start of 1944, the war was going against the Japanese on several fronts. They were being driven back in the central and southwest Pacific, and their merchant ships were under attack by Allied submarines and aircraft. In Southeast Asia, they had held their lines over the preceding year, but the Allies were preparing several offensives from India and the Chinese province of Yunnan into Burma. In particular, the town of Imphal in Manipur on the frontier between India and Burma was built up to be a substantial Allied logistic base, with airfields, encampments and supply dumps. Imphal was linked to a railhead at Dimapur in the Brahmaputra Valley by a road which wound for 100 miles (160 km) through the steep and forested Naga Hills.
Allied defensive arrangements
Imphal was held by the IV Corps (Lieutenant General Geoffry Scoones) part of the Fourteenth Army (Lieutenant-General William Slim). Because the Allies were planning to take the offensive, the corps' divisions were thrown forward almost to the Chindwin River and widely separated, vulnerable to being isolated and surrounded.
The Indian divisions were composed of British and Indian personnel. In each brigade, there was generally one British, one Gurkha and one Indian battalion, although two brigades (the 37th Brigade in the 23rd Division and 63rd Brigade in the 17th Division) were composed entirely of Gurkha units. Each division was supported by two field artillery regiments (usually British) and one Indian mountain artillery regiment.
Japanese offensive planning
Mutaguchi intended to exploit his planned capture of Imphal by advancing to the Brahmaputra Valley. This would cut the Allied lines of communication to the front in northern Burma, where the American-led Northern Combat Area Command was attempting to construct the Ledo Road to link India and China by land, and to the airfields supplying the Nationalist Chinese under Chiang Kai-shek via an airlift over "The Hump" (the Himalaya Mountains). Although the staffs at Burma Area Army and at Southern Expeditionary Army Group (the supreme command for the Japanese forces in southeast Asia and the southern Pacific) had reservations over the scale of Mutaguchi's proposed operation, they were eventually won over by his persistent advocacy. Finally, Prime Minister Hideki Tojo and Imperial General Headquarters gave their approval to the plan.
Mutaguchi intended to block the supply lines to the Allied units in their forward positions, to isolate and destroy them, drawing the Allied reserves into the battle and then capture Imphal. His plan was named U-Go, or Operation C. In detail:
- The 33rd Infantry Division under Lieutenant-General Motoso Yanagida would surround and destroy the 17th Indian Division at Tiddim, then attack Imphal from the south.
- Yamamoto Force, formed from units detached from the Japanese 33rd and 15th Divisions under Major-General Tsunoru Yamamoto (commander of 33rd Division's Infantry Group), would destroy the 20th Indian Division at Tamu, then attack Imphal from the east. The force was supported by the 14th Tank Regiment, equipped with 66 assorted tanks, under Lieutenant Colonel Nobuo Ueda and the 3rd Heavy Artillery Regiment under Lieutenant Colonel Kazuo Mitsui.
- The 15th Infantry Division under Lieutenant-General Masafumi Yamauchi would envelop Imphal from the north. This division was still arriving from road-building duties in Thailand and was understrength at the start of the operation.
- In a separate subsidiary operation, the 31st Infantry Division under Lieutenant-General Kotoku Sato would isolate Imphal by capturing Kohima on the Imphal-Dimapur road, and then advance to Dimapur.
At the insistence of Subhas Chandra Bose, leader of the Azad Hind (a movement which sought to overthrow British rule in India by force, with Japanese assistance), the Indian National Army made a substantial contribution. Originally, the Japanese intended using them only for reconnaissance and propaganda.
- Units of the First Division (initially the Subhas Brigade or 1st Guerrilla Regiment, less a battalion sent to the Arakan) covered the left flank of 33rd Division's advance.
- The 2nd Guerrilla Regiment was attached later in the battle to Yamamoto Force.
- The Special Services Group, redesignated the Bahadur Group, acted as scouts and pathfinders with the advanced Japanese units in the opening stages of the offensive. They were tasked to infiltrate through British lines and encourage units of the British Indian Army to defect.
All of Mutaguchi's divisional commanders disagreed with the plan to some extent. Sato distrusted Mutaguchi's motives, and Yanagida openly derided his abrasive superior as a "blockhead." Yamauchi was already very ill and fatalistic. Their main reservations concerned supply. Mutaguchi had assumed that success would be achieved within three weeks, but adequate supplies after that period could be obtained only if the Japanese captured Allied supply dumps, as the monsoon rains, which usually descended from about the middle of May, would make the supply routes from the Chindwin almost impossible to traverse. Gambles such as Mutaguchi was making had worked in the past, but could no longer be relied upon, given nearly total Allied air superiority in the area and the improvement in morale and training of British and Indian troops. Mutaguchi proposed to use "Genghis Khan" rations, driving herds of buffalo and cattle rounded up throughout northern Burma across the Chindwin as meat rations on the hoof. However, most of these beasts died from lack of forage and their meat rotted many miles from the troops they were intended to supply.
There were other weaknesses in the plan, which were revealed as the campaign progressed. The Japanese assumed that the British would be unable to use tanks on the steep jungle-covered hills around Imphal. For ease of movement and supply, the Japanese left behind most of their field artillery, their chief anti-tank weapon. As a result, their troops would have little protection against tanks.
Based on his experiences in the campaigns in Malaya and Singapore and in the Japanese conquest of Burma in early 1942, Mutaguchi dismissed British and Indian troops as inherently inferior. The troops he had met on those occasions had generally been inadequately trained and led. The Allies, under general William Slim, had by now largely overcome the administrative and organisational problems which had crippled their early efforts in Burma, and their troops were far better trained and motivated.
Prelude to the operation
In late February, a local Japanese counterattack was launched against Indian XV Corps in Arakan, using much the same tactics as Mutaguchi proposed to use. The engagement became known to the Allies as the Battle of the Admin Box, the "box" being the supply area for the brigades of the 7th Indian Infantry Division. The attack failed as Allied aircraft were able to parachute supplies to the cut-off troops, allowing them to stand firm, while the Japanese who had infiltrated behind them ran out of supplies. From this point onwards, the Allies were to rely increasingly on their transport aircraft. Also, the Japanese unexpectedly encountered tanks, to which the lightly equipped infiltrators had little counter. The planning of U-Go, however, was too far advanced to take account of these developments.
Even as the Japanese prepared to launch their attack, the Allies launched the airborne phase (Operation Thursday) of the second Chindit expedition on 5 March 1944. Japanese officers such as Major-General Noburo Tazoe, commanding the Japanese Army Air Force units in Burma, urged Mutaguchi to divert troops from his offensive to secure the Japanese rear areas against the Chindits. Mutaguchi dismissed these concerns, claiming that in a few weeks he would occupy the air bases from which the Chindits were supplied.
Opening phases of the battle
When they received intelligence that a major Japanese offensive was impending, Slim and Scoones planned to withdraw their forward divisions into the Imphal plain and force the Japanese to fight at the end of impossibly long and difficult lines of communication. However, they misjudged the date on which the Japanese were to attack, and the strength they would use against some objectives. The Japanese troops began to cross the Chindwin River on 8 March. Scoones gave his forward divisions orders to withdraw to Imphal only on 13 March.
Tamu–Shenam
The 20th Indian Division held Tamu near the Chindwin, and Moreh a short distance to the north, where a large supply dump had been established. On 20 March, there was a clash between six Lee medium tanks of the 3rd Carabiniers and six Type 95 Ha-Go tanks leading Yamamoto's advance from the south. The lighter Japanese tanks were destroyed. Acting major-general Douglas Gracey was opposed to making any retreat, but on 25 March he was ordered to detach some of his division to provide a reserve for IV Corps. As this left the division too weak to hold Tamu and Moreh, they withdrew to the Shenam Saddle, a complex of hills through which the Imphal-Tamu road ran. The supply dump at Moreh was set ablaze, and 200 cattle there were slaughtered. The division fell back without difficulty, mainly because two of Yamamoto Force's battalions from the Japanese 15th Division (II/51 Regiment and III/60 Regiment) were delayed at Indaw in northern Burma by the Chindits and were unable to intervene.