On 7 December 1941 the Japanese attacked the US naval base at Pearl Harbour and later declared war on Britain and the United States. In the days and weeks that followed the Japanese invaded European colonies across East Asia, including the British territories of Hong Kong, Malaya, Singapore and Burma. The purpose of these campaigns was to create a fortified perimeter around a self-sufficient Japan, which could be defended until the Allies tired of the war.
The British had long thought a Japanese land invasion of Burma unlikely so its defences had been neglected. When the attack began in January 1942 the British position quickly deteriorated and by early March the capital Rangoon and its vital port had been lost. As the Japanese pushed northwards, the surviving Allied troops under General Sir Harold Alexander carried out a five-month fighting retreat to India across 1,000 miles (1,600km) of difficult terrain.
In November 1943 a new phase of the war in the Far East began with the formation of South East Asia Command (SEAC) under Admiral Lord Louis Mountbatten. SEAC replaced India Command in control of operations and under its leadership the prosecution of the war took on a new energy. Previously, British troops had fallen back when the Japanese cut their lines of communication, and operations had practically ceased during the monsoon. Now the policy was to stand firm and rely on air supply when cut off, and to fight on through the harshest conditions.
In March 1944 the Japanese 15th Army began an advance against India’s north-east frontier to forestall a planned British invasion of Burma. They intended to capture the British supply bases on the Imphal Plain and cut the road linking Dimapur and Imphal at Kohima. With Imphal in their hands, the Japanese would also be able to interrupt air supplies to China. It would also give them a base from which to conduct air attacks against India. A Japanese diversionary attack in the Arakan was defeated at the battle of the Admin Box, but in early April the troops at Kohima and Imphal were surrounded.
The plan to attack Imphal originated with Lieutenant-General Renya Mutaguchi (1888-1966), a veteran of campaigns in China, Malaya and Singapore. He led three Japanese divisions and one Indian National Army division. Mutaguchi was stubborn and quarreled with his divisional commanders during the campaign. The 31st Division, sent to attack Kohima, was led by Lieutenant-General Kotoku Sato (1893-1959). He considered Mutaguchi to be a ‘blockhead.’
Lieutenant-General Geoffrey Scoones (1893-1975) commanded 4th Corps at Imphal. This included the 17th, 20th and 23rd Indian Divisions. The 5th Indian Division, airlifted in as the battle developed, joined them there. Colonel Hugh Richards (d.1983), formerly of the Chindits, commanded the 2,500-strong Kohima garrison. Lieutenant-General Montagu Stopford (1892-1971) led 33rd Corps, which relieved Kohima and Imphal.
Overall command of British-Indian forces during the campaign fell to Lieutenant-General William Slim (1891-1970) commander of Fourteenth Army. Slim was responsible for restoring the morale of the soldiers following the setbacks of 1942-43. He emphasised the need for jungle warfare training and the use of more aggressive tactics that included the formation by surrounded units of defensive 'boxes' that were supplied by air.
Imphal, capital of Manipur state, lay in a plain surrounded by hills. The main British base in the area, it was held by Lieutenant-General Scoones’ 4th Corps of Fourteenth Army. Lieutenant-General Renya Mutaguchi’s plan relied on his men quickly annihilating 4th Corps and seizing its supplies before his own communications and logistics broke down. The Japanese 33rd Division would cut off the 17th Indian Division south of Imphal and shortly afterwards the 15th Division would attack from the north-east, severing the road to Kohima, some 80 miles (120km) away in Nagaland. Lieutenant-General Kotoku Sato’s 31st Division would simultaneously surround Kohima to prevent any relief from Dimapur, which was a further 40 miles (64km) to the north.
The Japanese offensive started well. On 29 March they cut the Imphal-Kohima road and almost surrounded the 17th Division. They then quickly isolated the hilltop town of Kohima, capturing all but the central ridge by mid-April. The commander at Kohima, Colonel Hugh Richards, had hastily organised a scratch force from his 2,500-strong garrison, many of whom were non-combatants. It was built around 4th Battalion, The Queen’s Own Royal West Kent Regiment and the Assam Regiment. Elements of 161st Indian Brigade, stationed at Jotsoma two miles to the west, also reinforced the garrison.
Faced by 15,000 Japanese, the British-Indian troops held a tight defensive perimeter centred on Garrison Hill. Between 5 and 18 April Kohima saw some of the bitterest close-quarter fighting of the war. In one sector, only the width of the town’s tennis court separated the two sides. When on 18 April the relief forces of the British 2nd Division arrived, Richards’s defensive perimeter was reduced to a shell-shattered area only 350 metres square.
Mutaguchi had underestimated his enemy’s defensive skills. Likewise he misjudged the Allies’ ability to bring up reinforcements. Mountbatten had immediately despatched the 2nd Division from India by road and rail to Dimapur where it joined 33rd Corps under Lieutenant-General Montagu Stopford for the bitterly contested march to relieve Kohima. On 14 April the British broke the Japanese roadblock at Zubza and reached Kohima four days later. Despite the arrival of the reinforcements, the battle continued to rage around Kohima until mid-May when Sato’s division began to withdraw. Stopford's men, assisted by 2nd Division, then cleared the road to Imphal and on 22 June they linked up with 4th Corps.
The latter had been under siege since 5 April. The Japanese made several attacks against Imphal’s defensive perimeter, particularly on the Nungshigum heights and in the Palel area, but the 5th, 17th, 20th and 23rd Indian Divisions held firm. The commander of Fourteenth Army, Lieutenant-General William Slim, outlined their struggle:
‘The fighting all around its circumference was continuous, fierce, and often confused as each side manoeuvred to outwit and kill. There was always a Japanese thrust somewhere that had to be met and destroyed. Yet, the fighting did follow a pattern. The main encounters were on the spokes of the wheel, because it was only along these that guns, tanks, and vehicles could move.’
Allied logistical and communications superiority were key. They had not only allowed the quick deployment of reinforcements from Dimapur, but also the airlifting of 5th Indian Division and its equipment from the Arakan to Imphal in only two days. During the battle the Royal Air Force flew in nearly 19,000 tons of supplies and over 12,000 men, and evacuated around 13,000 casualties. Continually supplied by air, the garrisons threw back the Japanese attacks in bitter close-quarter fighting until the relief forces reached them.
The Japanese could have withdrawn fairly easily had Mutagachi not insisted on continuing the offensive long after it was clear that it had failed. His plan had relied on using captured supplies and when these were not forthcoming his men starved in the worst of the monsoon conditions. The Japanese 15th Army, 85,000-strong, eventually lost 53,000 dead and missing. The British sustained 12,500 casualties at Imphal while the fighting at Kohima cost them another 4,000 casualties.
Imphal-Kohima was one of the biggest defeats the Japanese Army ever suffered. Mutaguchi was relieved of command and recalled to Tokyo. He was forced into retirement in December 1944. That same month, in a ceremony at Imphal, the viceroy of India Lord Wavell knighted Slim, Scoones and Stopford.
After their defensive victory the British planned a new offensive aimed at clearing the last Japanese forces from northern Burma and driving them south towards Mandalay and Meiktila. Fighting through the monsoon and supplied by air, troops of the Fourteenth Army now crossed the River Chindwin. The 15th Corps took Akyab in the Arakan, while 4th and 32nd Corps won bridgeheads across the River Irrawaddy. After fierce fighting Meiktila and Mandalay were captured in March 1945.
It was a decisive victory won through the courage and endurance of the troops and the superb generalship of their commanders. The route south to Rangoon now lay open and 4th Corps was only 30 miles (48km) from the city when it fell to a combined air and seaborne operation in early May.
The India Peace Memorial, situated at Red Hill (Lotpaching), about ten miles (16km) from Imphal, commemorates the Japanese and Indian National Army (INA) troops who fell in the fighting. It was inaugurated in March 1994 on the 50th anniversary of the battle following the efforts of Japanese and INA veterans to obtain a memorial. There is also a monument dedicated to the INA at nearby Moirang, where, on 4 April 1944, the Indian tricolour (flag) was first unfurled on the mainland. Moirang also has a statue of INA leader Subhas Chandra Bose and a museum about his troops.
The Commonwealth War Graves Commission cemetery at Imphal contains 1,600 graves and that at Kohima 1,420. There are also several monuments to British and Indian units that fought at Kohima as well as the Kohima Cremation Memorial that commemorates the 917 Hindus and Sikhs killed there. The cemetery lies on the slopes of Garrison Hill and also contains the British 2nd Division’s memorial. The inscription on the latter has become famous as the ‘Kohima Epitaph’. Attributed to John Maxwell Edmonds, it reads:
‘When You Go Home,
Tell Them Of Us And Say,
For Your Tomorrow,
We Gave Our Today’
In Britain both battles are memorialised by displays at the Kohima Museum at Imphal Barracks, York. They are also commemorated by the work of organisations such as the Burma Star Association, founded in 1951 to assist veterans of the Burma fighting, and the Burma Campaign Society, an organisation set up to bring about reconciliation between Japanese and British soldiers and their descendants. The Kohima Trust also commemorates the battle by providing educational assistance to young people in Nagaland as a way of honouring the help given to the British by the Nagas in 1944.