In December 1941, nearly a decade before the start of the Korean War, the Japanese invaded Burma with a well armed, well supplied, and well equipped contingent of 35,000 troops backed up by basically unfettered air support. They advanced northward into the interior almost unimpeded, with the capitol, Rangoon, falling March 6-7, 1942. They were also successful in shutting down the Allies' life-line into China, the Burma Road. During that period, on December 7, 1941, Japanese forces attacked Pearl Harbor opening the door for the U.S. entry into World War II. Two days later, December 9, 1941, China declared war on Japan.
China, had however, been in a full-scale war with Japan since at least July 1937 when the Japanese claimed they were fired upon by Chinese troops at the Marco Polo Bridge near Beijing. From that the Japanese retaliated by launching an invasion from Manchuria. By November 1937 Shanghai, China's most important sea port fell followed by Nanking, Chiang Kai-shek’s capital, in December 1937.
On February 4, 1942, close on the heels of the Japanese invasion of Burma and just before the fall of Rangoon, Chiang Kai-shek flew over the Hump on a secret mission into India in an effort to convince British and Indian leaders, military and otherwise, that as soon as Japan solidified their positions in Burma they would be setting their sights on India and anything that could be done in the meantime to impact that solidification adversely would impede or possibly stop any of their designs on India.
True to Chiang's words, soon as 1944 rolled around, with Burma mostly under control, the Japanese began formulating invasion plans which, even in those early stages, had been given a codename, Operation U Go. Part of the U Go plan included soldiers of the Indian National Army joining the Japanese and fighting along side Imperial Army troops as they entered India, with the idea being for Japan to be viewed by the Indian populace more as a liberation force rather than an invasion force. The Indian National Army, whose only reason for existence was to remove the yoke of their British overlords, had been convinced by Japan that by combining forces they could in fact overthrow British and European rule just as the Japanese had, up to that point, all over Asia.
On April 5. 1944, Japanese troops, under the command of Major-General Shigesaburo, with a low-profile assist by the Indian National Army, launched an attack into India against Kohima. However, although initially Japanese advances met a certain amount of success in the early stages, as the opening quote at the top of the page states, in the end it didn't work out.