Fact File : Defence of Imphal and Kohima
7 March to 18 July 1944
Theatre: South East Asia
Area: Northern Burma and north east India.
Players: Allies: 4th Corps under General Geoffrey Scoones; 15th Corps under General Philip Christison; 33rd Corps under Lieutenant General Montagu Stopford; Kohima Garrison under Colonel Richards. Japan: 15th Army under Lieutenant General Renya Mutagachi.
Outcome: An audacious Japanese offensive into India was defeated by superior Allied forces, aided by tactical mistakes made by the Japanese commander.
Large reinforcements of British troops in north east India during 1943 prompted the Japanese to launch a pre-emptive offensive from Burma into the Indian province of Assam.
The Japanese did not want to invade India, but instead hoped to prevent an Allied offensive in the dry season in 1944 by occupying the Imphal plain and controlling the mountain passes from Assam.
The offensive was launched in March 1944 with three divisions. The British 4th Corps was scattered, with the southernmost division bypassed by the Japanese, blocking its means of retreat to Imphal. The Japanese advance from the River Chindwin also prompted the 20th Division to withdraw.
On 19 March the Japanese attacked Ukhrul, a town 50km (30 miles) behind Imphal. At that point it became obvious that the real target of the offensive was Kohima, 95km (60 miles) north of Imphal, on the road back across the mountains into India.
For a brief period on 29 March, the Imphal-Kohima road was cut - until two more divisions were sent forward as a safeguard. The Japanese offensive had managed to throw their numerically superior opponents off balance.
The British had more than four divisions on the Imphal plain, but Kohima was defended by only 1,500 troops. However, disaster was averted for the British when Mutagachi was refused permission to push on and seize Dimapur, 50km (30 miles) behind Kohima, which would have severely disrupted any British counter-offensive.
As it was, Stopford and some of his 33rd Corps were moved forward from India. On 2 April, he was given command of the Dimapur-Imphal area and awaited the rest of his corps. The Japanese began their attack on Kohima on the night of 4 April and quickly seized the dominating heights around the town, cutting off the Kohima garrison from its reinforcements, who themselves were cut off from Dimapur by a Japanese roadblock at Zubza.
General William Slim, commander of the 14th Army, ordered a general counter-offensive on 10 April. On 14 April, the British broke the roadblock at Zubza and on 18 April reinforcements broke through to the garrison at Kohima, just as it was making its last stand.
At Imphal, two British divisions counter-attacked north, to clear the road to Kohima, and north east, to threaten the rear of the Japanese division attacking Kohima. The other two British divisions moved south.
In May, Stopford's brigade cleared the road to Imphal, while Scoones's troops almost managed to corner the Japanese south of there. The Japanese could have withdrawn easily, and with minimal losses, had Mutagachi not insisted on continuing his offensive long after it became clear that he had no hope of success. Opposed by his three divisional commanders, he fired them all.
The British counter-offensive continued during July and eventually reached the River Chindwin, delayed more by the monsoon than the exhausted and depleted Japanese troops. They had suffered 50,000 casualties out of the 84,000 troops involved, while the British lost fewer than 17,000 men out of a much larger strength. The Japanese loss would weigh heavily on them in the next phase of the war in Burma.
The fact files in this timeline were commissioned by the BBC in June 2003 and September 2005. Find out more about the authors who wrote them.