Battles of Imphal and Kohima (1944): Turning the Tide in Burma

The Battles of Imphal and Kohima, fought from March to July 1944 in the hills of north-east India, ended Japan’s attempt to invade British India. The Japanese 15th Army besieged the town of Kohima and the plain of Imphal, but the British and Indian troops of General William Slim’s Fourteenth Army held on, supplied by air, and then counter-attacked. The defeat was the largest suffered by the Japanese army up to that time and opened the way for the Allied reconquest of Burma.

Background: the war on the Burma front

Japan had conquered Burma in 1942, driving British and Indian forces back across the mountains into India after the Fall of Singapore and the collapse of Allied positions in South-East Asia. Burma protected Japan’s western flank and cut the Burma Road, the main overland route for supplying China.

By early 1944 the Allies were preparing to return. The British built up a large base on the Imphal plain in Manipur, linked to the railway in Assam by a single road through Kohima, a hill station in the Naga Hills. Lieutenant-General Renya Mutaguchi, commander of the Japanese 15th Army, argued that a pre-emptive strike could seize Imphal, capture its supplies and perhaps open the way into India.

At the same time, Major-General Orde Wingate’s Chindits, a long-range penetration force, were flown deep behind Japanese lines in Operation Thursday from 5 March 1944 to disrupt communications in northern Burma. Their operations ran alongside the battles in India but did not prevent the Japanese offensive.

Operation U-Go

The offensive, codenamed U-Go, involved three Japanese divisions, the 15th, 31st and 33rd, with around 85,000–100,000 men, supported by units of the Indian National Army, which had been raised from Indian prisoners of war and expatriates under the nationalist leader Subhas Chandra Bose. The plan relied on speed: troops carried only about three weeks of rations and expected to live off captured British stores.

The 33rd Division moved first in early March 1944, and the main crossings of the Chindwin River followed around 15 March. Slim had expected an attack but was surprised by its timing and strength. He withdrew IV Corps, under Lieutenant-General Geoffry Scoones, into a defensive “box” around Imphal and flew in reinforcements, including the 5th Indian Division, which was moved by air from the Arakan front.

The siege of Kohima

Mutaguchi sent the 31st Division under Lieutenant-General Kōtoku Satō across the mountains to cut the road at Kohima. Its main defence was a garrison of about 1,500 men, built around the 4th Battalion, Queen’s Own Royal West Kent Regiment, the Assam Regiment and the Assam Rifles, under Colonel Hugh Richards. From about 5 April they were surrounded on a narrow ridge by a force many times larger.

For two weeks the defenders were pushed back into an ever smaller area. Water ran short, the wounded lay in the open, and supplies dropped from aircraft often fell into Japanese lines. Some of the fiercest fighting took place across the tennis court beside the bungalow of the Deputy Commissioner, Charles Pawsey, where the two sides threw grenades at each other at a distance of only a few metres. On 18 April troops of the British 2nd Division and the 161st Indian Brigade broke through and relieved the garrison.

The siege of Imphal and the Japanese retreat

Imphal was cut off from the end of March. Around 150,000 troops and many civilians on the plain depended on an airlift by British and American transport aircraft, which brought in food, ammunition and reinforcements and flew out tens of thousands of wounded and non-combatants. Japanese attacks on the hills around the plain, at places such as Sangshak, Nungshigum, Bishenpur and the Shenam Saddle, were repeatedly beaten off.

The Japanese, by contrast, had almost no supplies. As the monsoon broke in May, their soldiers suffered from hunger, malaria, dysentery and exhaustion. At the end of May Satō, whose division was starving, withdrew from Kohima against orders, and was later relieved of command.

The British 2nd Division and Indian units fought for weeks to clear the Kohima ridge, which was not fully taken until mid-May. They then pushed south along the road towards Imphal. On 22 June the relieving force met troops advancing north from Imphal near Milestone 109, reopening the road and ending a siege that had lasted nearly three months.

Mutaguchi finally called off the offensive in early July 1944. The retreat to the Chindwin in monsoon rain became a disaster, and the track used by the retreating troops was later remembered in Japan as a “road of bones” because of the many dead left along it.

Key people

• William Slim, commander of the Fourteenth Army, whose flexible defence and use of air supply made victory possible.
• Renya Mutaguchi, commander of the Japanese 15th Army, who planned the offensive and pressed it long after it had failed.
• Kōtoku Satō, commander of the 31st Division, whose withdrawal from Kohima defied his superiors.
• Hugh Richards, the colonel who commanded the Kohima garrison during the siege.
• Subhas Chandra Bose, leader of the Indian National Army, which fought alongside the Japanese.

By the numbers

Consequences

The Japanese 15th Army never recovered. In late 1944 and 1945 Slim’s Fourteenth Army crossed the Chindwin and the Irrawaddy, won the Battle of Meiktila and Mandalay in early 1945, and Rangoon was retaken in May 1945. The campaign showed the power of air supply, close cooperation between ground and air forces and a well-trained, largely Indian army; most of the soldiers who fought at Imphal and Kohima were Indian or Gurkha, fighting alongside British units. Japan’s war in South-East Asia ended with the surrender of Japan in August 1945.

Legacy

The Kohima War Cemetery, laid out on the slopes of Garrison Hill, preserves the outline of the tennis court with white markers. Its 2nd Division memorial bears the Kohima Epitaph, attributed to John Maxwell Edmonds: “When you go home, tell them of us and say, for your tomorrow, we gave our today.” In 2013 a public vote held by the National Army Museum named Imphal and Kohima Britain’s greatest battle.

The fighting also affected the Naga and Manipuri peoples of the region, whose villages were caught in the battle and many of whom served as guides, porters and scouts for the Allies. Their part in the battle has received more recognition in recent decades.

Timeline

• 1944, early March: Japanese 33rd Division begins its advance on Imphal.
• 1944, c. 15 March: Main Japanese forces cross the Chindwin River.
• 1944, 5 April: The siege of Kohima begins.
• 1944, 18 April: The Kohima garrison is relieved.
• 1944, 31 May: Satō begins withdrawing from Kohima.
• 1944, 22 June: The Imphal–Kohima road is reopened at Milestone 109.
• 1944, early July: Mutaguchi calls off the offensive.

Why it matters

Imphal and Kohima was the turning point of the war in Burma. It stopped Japan’s only major invasion of India, destroyed an entire Japanese army and paved the way for the liberation of Burma in 1945.