During the following year, the Army remained as a garrison force in Burma, defeating an Allied offensive in Arakan and inflicting heavy casualties on a long-range penetration raid under Orde Wingate.

Mutaguchi, his chief of staff, and several other officers were removed in the aftermath, and Lieutenant General Shihachi Katamura was assigned to command.

As the monsoon season ended, the remnants of the Fifteenth Army attempted to forestall an Allied offensive into Burma by withdrawing behind the Irrawaddy River.

They were unable to prevent British and Indian troops from securing bridgeheads across the river, and the army was weakened by losses and detachments to other parts of the front.

Once Mandalay was captured, the Fifteenth Army could only retreat southwards, badly disorganised and was further depleted in the failed Japanese breakout of the Pegu Yomas in July and August 1945.