Here's just a brief taste ... read the whole thing and the links to more detail. What an incredible battle by a combined force.
...Mutagushi ordered 2 of his divisions, the 15th & 33rd to encircle and destroy the British and Indian forces on the Imphal Plain. His 3rd Division, the 31st, commanded by Lt Gen Sato was to strike west to cut the road between the great supply depot and railhead at Dimapur thus preventing reinforcements from going to the aid of IV Corps. The road was to be cut at the small hill station of Kohima which sat at the pass through the hills. Once this was achieved, Mutagushi further planned to head off into India proper. He had been convinced that the Indians would then rise up in support against the British. This, the Japanese claimed, was the start of their march on Delhi.
The British of course knew that the Japanese were heading towards Kohima but they didn’t fully appreciate the numbers and the speed of approach. The Japanese 31st Division comprised about 13,500 men!!
Kohima was almost like a transit camp, with soldiers coming and going all of the time as the buildup in Imphal progressed, there was a field bakery, a hospital, vehicle repairs, a leave camp and a battle casualty reinforcement camp. With the constant movement of men, the best estimate is that the Garrison, commanded by Colonel H.U.W. Richards, consisted of about 1,500 combatant troops. These were mainly about 420 officers & men from the 4th battalion of the Queens Own Royal West Kent regiment who together with the remainder of their brigade, the 161st from 5th Indian Division had been airlifted out from the Arakan to meet the threat.
Elements of the Assam Rifles and Assam Regiment together with the soldiers from the leave & reinforcement camp formed the remainder.
The Japanese left behind around 7,000 dead and the British & Indian Army had around 4,000 casualties.
In the aftermath of the battle it has been said that there have been longer sieges but there have been fewer that were bloodier.
This was a battle in which everyone took part. There were no onlookers and the fighting was hand to hand for the most part. No-one was spared and 2 more Brigadiers were killed as were 5 Commanding Officers as testimony to the ferocity of the fighting.
The Battle of Kohima, in the opinion of many, was the decisive period of the Burmacampaign. Had Kohima fallen it is difficult to see how Imphal could have been relieved in time.