The Battle of Imphal was fought simultaneously with the Battle of Kohima & consisted of several concurrent independent battles fought across the flat Imphal Plain & the jungle-covered hills that surround it.
Imphal is the capital of Manipur State, the most eastern province of India situated next to Burma, a British colony that fell to the Japanese in 1942.
In March 1944, Indian 4 Corps was based at Imphal. Its 17 & 20 Divisions were isolated near the frontier in vulnerable positions, intended as bait. If attacked, they would fall back to Imphal, enticing the Japanese away from their supply bases. The concentration of Allied forces at Imphal was likened by Lt General Slim to a tethered goat, that would lure the Japanese to their destruction.
Lt General Mutaguchi did what the Allies hoped, sending one division against each of the exposed Indian divisions. But he wrong-footed the Allies by sending his third division (31) to Kohima, cutting the road that kept Imphal supplied. This caused a crisis.
Dispersed amongst the three Japanese divisions was the Indian National Army, which aimed to incite the population of India to rise up against British colonial rule. They were unsuccessful.
17 Division was located around Tiddim, 150 miles south of Imphal. Slow to respond to the invasion, it was nearly cut off, but 4 Corps reserve (23 Division) arrived just in time to keep open the road back to Imphal.
Sending the reserve south left Imphal vulnerable to attack from the north. 50 Indian Parachute Brigade provided temporary cover, with an heroic stand at Sangshak that delayed the Japanese advance.
The crisis was averted by flying Indian 5 Division into Imphal, the largest airlift in history. Air superiority & a huge transport fleet was decisive for the Allied victory. By the end of the battle, 12,000 men had been flown in & 13,000 casualties flown out. The air force also kept Imphal supplied after its road link was cut, delivering 19,000 tons of food, fuel & munitions.
Attacking from the north, the Japanese seized Nunshigum Ridge that overlooked one of the airfields, threatening the air lifeline of 4 Corps. Supported by 5 Division, Lee tanks climbed the steep slopes onto the Ridge to drive off the Japanese.
The closest to Imphal reached by any substantial force of Japanese was Nunshigum, a huge massif that dominates the northern end of the Imphal Plain. The summit is not a single peak but a narrow ridge about four miles long with a series of peaks, the highest a thousand feet above the valley floor.
(from ‘Burma: The Longest War’ by Louis Allen)
Nunshigum was a crucial position, only six miles from 4 Corps HQ & closer still to a vital airfield, as well as fuel & ammunition dumps. A crisis began when a Japanese battalion of 15th Division seized it after bitter fighting with 3/9th Jats of 5th Indian Division.
The Allies responded with overwhelming force. On April 13, the Japanese on Nunshigum were attacked by three RAF squadrons, pounded by the massed artillery of 5th Division, & then assaulted by the 1/17th Dogras & Lee tanks of B Squadron 3rd Carabiniers.
The slopes were so steep that the tanks could only climb in first gear, at only one mile an hour. With a gradient of 1:2, the drivers could not see the ground, so a courageous officer walked ahead, directing the tanks with hand signals. The Dogras advanced cautiously through the scrub behind & beside the tanks.
The ridgeline was a knife-edge, almost 45o on either side & so narrow that the tanks had to go in single file. One tank toppled over, so the tank commanders were forced to direct their drivers from open hatches, with their heads & shoulders exposed.
Incredibly vulnerable, the tank commanders were picked off one-by-one by Japanese rifle fire. Other tank crew who took over were also shot down. The Dogras too sustained heavy casualties until every tank & infantry officer was wounded or killed.
Squadron Sergeant-Major Craddock took command & pressed home the attack until his tank mounted the ‘bump’ where Japanese bunkers were located & buried their occupants. The Dogras overran the enemy positions & clinched victory with grenades & bayonets.
A commemoration of this engagement is held annually on the anniversary by the Royal Scots Dragoon Guards, the unit created by amalgamation of the 3rd Carabiniers & the Royal Scots Greys, in which B Squadron parades without officers, under command of the Squadron Sergeant-Major & NCOs.
South-east of Imphal, Indian troops repulsed an attack by the Indian National Army on the airport at Palel.
Indian 20 Division defended the main road from Tamu. This was the only road that the Japanese could use to bring tanks & heavy artillery close enough to attack Imphal. Both sides took heavy losses as positions changed hands.
Japanese attacks ground to a halt in May, due to crippling casualties & inadequate supply. Mutaguchi replaced his divisional commanders, who no longer believed they could win. The change of leadership led to fresh attacks, but desperate fighting failed to shift the Indians & drained the remaining strength of the Japanese.
5 Division pushed north & on June 22 met up with British 2 Division advancing south from Kohima. Supplies could now reach Imphal by road & the siege was over. Mutaguchi demanded more attacks, but his forces were no longer capable, so he ended the offensive on July 3. The invasion of India had failed.
Casualties for the Battle of Imphal were estimated as approximately 12,600 for the Allies & 54,900 for the Japanese.
