What was the fighting in Burma, Papua New Guinea & Indochina about during WW2?

Question:

how much of the Japanese forces were in these areas and roughly when ? who they were figthing and how and how the Americans came into fighting with the Japanese? (after Pearl Harbour)

Answer:

The fighting in the Japanese War was "about" Japan's absolute need for supplies of oil. Their attempt to get them by seizing Russian oil-fields had been defeated at Nomohan (in Mongolia), forcing them to turn to the oil-fields of the East Indies, These were in the possession of the Dutch and the,British, so, when Hitler over-ran the Netherlands, and Britain stood alone, under heavy pressure at sea and in North Africa, the Japanese struck.- the landings in Malaya and the Dutch East Indies took place at the same time as the attack on Pearl Harbour. Malaya led to Burma, Java and Sumatra led to the other islands in the "chain".and the "extremities" of Japanese expansion eventually were Guadalcanal, and New Guinea, and the Burma-India frontier. At these places the "tide" was turned by the Australians and Americans in the South, and the British and Indians in the North. From then on, the Japanese forces were relentlessly destroyed by the Americans "island-hopping" North-westward across the Pacific, and the British driving South - even during the monsoon - through Burma. The ultimate invasion of Japan was, of course, rendered unnecessary by the dropping of the atomic bombs on Hiroshima and Nagasaki, which brought about the Japanese surrender.