With Japan's limited resources towards the end of that conflict, the entire IJA was committed to combat in Manchuria, leaving not a single division to guard the Japanese home islands from attack.

Under the command of Lieutenant General Yoshio Iwamatsu, it was assigned to the Chinese mainland as a garrison force around Nanjing and to maintain public safety over Japanese-occupied areas.

During these operations, the division lost more than half of its men in combat or due to disease, and was forced out of Burma into Thailand in August 1945 days before the end of the war, where it was officially disbanded.

Thus, the 15th Division started the campaign with 6 battalions, 18 guns and a commander, Lieutenant-General Masafumi Yamauchi, who mortally ill with tuberculosis.

The British counterattack on this ridge included M3 Lee tanks, which came as a shock to the Japanese as they had considered the terrain to be completely impassable to armored vehicles.

On 7 July the division received orders for a last-ditch attack on Pallel, but by now it had been shattered as a military formation; its remnants retreated back across the Chindwin River to safety.

The opposing, Indian 19th Infantry Division, established its first bridgeheads on the eastern side of the Irrawaddy on 14 January and all attempts to dislodge them failed.

Of the two main positions, the Japanese were driven off Mandalay Hill by 12 March, but the thick walls of Fort Dufferin withstood artillery and air bombardment.

The survivors of the 15th Division (less than half its original strength of 15,000 men) retreated via the territory of the hostile Karen people and through the Southern Shan States, back into Kachanaburi, Thailand, where it remained at the time of the surrender of Japan 15 August 1945.