The Japanese commander in Burma, Lieutenant General Shōjirō Iida, was asked for his opinion on whether a renewed advance should be made into India after the rains ended.

One of its subordinate formations, responsible for the central part of the front facing Imphal and Assam, was the Fifteenth Army, whose new commander was Lieutenant-General Renya Mutaguchi.

In late 1942, when he was consulted by Lieutenant General Iida about the advisability of continuing the Japanese advance, he had been particularly vocal in his opposition, as the terrain appeared to be too difficult and the logistic problems seemed impossible to overcome.

[5] The Allies had widely publicised the successful aspects of Wingate's expedition while concealing their losses to disease and exhaustion, misleading Mutaguchi and some of his staff as to the difficulties they would later face.

Mutaguchi's Chief of Staff, Major General Todai Kunomura, presented Mutaguchi's plan, but was brusquely overruled as the staff of Burma Area Army objected to Kunomura pre-empting their own limited plans to push the Japanese forward defensive lines a short distance into the mountainous frontier with India.

Lieutenant General Inada was still opposed, but put forward to Kunomura and Major Iwaichi Fujiwara (one of Mutaguchi's staff officers) the apparently frivolous idea of attacking into the Chinese province of Yunnan instead.

However, Inada was removed from Southern Expeditionary Army on 11 October 1943, after being made the scapegoat for failures to comply with an agreement to cede territories to Thailand which, under Field Marshal Plaek Pibulsonggram, was allied to Japan.

[8] After another map exercise in Singapore on 23 December 1943, Field Marshal Hisaichi Terauchi (Commander in Chief of Southern Expeditionary Army Group) approved the plan.

[9] Once this decision was taken, neither Lieutenant General Kawabe nor Field Marshal Terauchi were given any opportunity to call off Mutaguchi's attack, codenamed U-GO or Operation C (ウ号作戦), nor to exercise much control over it once it was launched.

To some extent, Mutaguchi and Tojo were influenced by Subhas Chandra Bose, who led the Azad Hind, a movement which was dedicated to freeing India from British rule.

Bose was also commander in chief of the movement's armed forces, the Azad Hind Fauj or Indian National Army (INA).

The Japanese planned that a division from the Twenty-Eighth Army would launch a diversionary attack in the Arakan, codenamed Ha Go, in the first week of February.

In the centre, Mutaguchi's Fifteenth Army would launch the main attack into Manipur in the first week in March, aiming to capture Imphal and Kohima, scattering British forces and forestalling any offensive movements against Burma.

In early 1944, the Allied formations in Assam and Arakan were part of the British Fourteenth Army, commanded by Lieutenant General William Slim.

Over the preceding year, since the failure of an earlier offensive in the Arakan, he and his predecessor, General George Giffard, had been striving to improve the health, training and morale of the British and Indian units of the army.

Although a detachment continued to fight rearguard actions to block the road, XXXIII Corps drove south to link up with the defenders of Imphal on 22 June.

Mutaguchi continued to order fresh attacks, but by late June it was clear that the starving and disease-ridden Japanese formations were in no state to obey.

The Japanese, reduced in many cases to a rabble, fell back to the Chindwin, abandoning their artillery, transport, and soldiers too sick to walk.