From May to December 1942, most active campaigning ceased as the monsoon rains made tactical movement almost impossible in the forested and mountainous border between India and Burma, and both the Allies and Japanese faced severe logistical constraints.

British military efforts were instead concentrated on the Middle Eastern theatre, partly in accordance with the declared "Germany First" policy of the United States government under President Franklin Roosevelt.

In the aftermath of the Allied military disasters in the early months of 1942, there were violent Quit India movement protests in Bengal and Bihar,[6] which required large numbers of British troops to suppress.

Although the immediate causes were a typhoon which devastated large areas in October 1942 and a premature scorched earth operation in Eastern Bengal to deny resources to the Japanese in case of invasion, the reserves of food available for relief were reduced by the loss of rice normally imported from Burma and Allied demands for exported rice in other theatres, while the dislocation caused by sporadic Japanese bombing, and corruption and inefficiency in the government of Bengal prevented any proper distribution of aid, or other drastic measures being taken for several months.

Lieutenant General Shojiro Iida, commander of the Japanese Fifteenth Army, was asked by higher headquarters for his opinion as to whether to resume the offensive after the rains stopped.

The Indian Eastern Army under Lieutenant General Noel Irwin intended to reoccupy the Mayu peninsula and Akyab Island, which held an important airfield.

Here they were halted by a small Japanese force (initially of only two battalions but with heavy artillery support)[10] which occupied nearly impregnable bunkers.

Indian and British troops made repeated frontal assaults without armoured support, and were thrown back with heavy casualties.

Crossing rivers and mountain ranges which the Allies had assumed to be impassable, they hit 14th Division's exposed left flank on 3 April 1943 and overran several units.

The exhausted units which the division had inherited were unable to hold this line and were forced to abandon much equipment and fall back almost to the Indian frontier.

[citation needed] There was continual patrol activity and low-key fighting on the frontier south of Imphal, but neither army possessed the resources to mount decisive operations.

At American insistence, one of the overriding Allied strategic aims was the maintenance of supplies to the Nationalist Chinese government under Chiang Kai-shek.

[19] At the insistence of the American Joseph Stilwell, who was chief of staff to Chiang Kai-shek among other appointments, the Allies also began construct the Ledo Road to link India with China, which was to prove an enormous engineering task.

As part of the preparations to drive this road through Japanese-occupied northern and eastern Burma, two divisions of Chinese troops who had retreated into India in 1942 were re-equipped and trained by the Americans at camps in Ramgarh in Bihar.

Following Wingate's raid and the expansion of his force for the campaigning season of 1943–1944, the Americans also formed the long-range penetration unit which later became known as Merrill's Marauders and deployed them to Ledo.

Liaison and engineering parties were flown or parachuted into Fort Hertz, and a locally raised irregular force, the Kachin Levies, was established.

The Commander-in-Chief, India, General Archibald Wavell, was responsible for operations in Persia and Iraq (where there had been fears of a breakthrough by German forces in North Africa and the Caucasus until late 1942) and against the Japanese in Burma, and also for internal security in wide areas of India and the administration of the rapidly expanding Indian Army.

[22] In August 1943, the new Allied South East Asia Command was created, to take over control and planning of operations against the Japanese in Burma and the Indian Ocean.

From the moment he took charge, Mutaguchi forcefully advocated a bold offensive into India for the following year, in contrast to his earlier dismissal of the chances of such an attack succeeding.