Joining the war Japan proceeded their war of conquest throughout the Pacific nearly unhamperedly until 1941. However, the frivolous attack of Pearl Harbour and the immediate entry of the Americans into the war heralded their slow but irresistible downfall. Even initial successes of the Japanese forces like the conquest of Singapore were quickly undone by the achievements of the allies like the Burman victory by Australian troops. 1941: Unexpectedly the Japanese attack Pearl Harbor. America wants to take revenge. February 1942: Singapore surrenders to Japan September 1942: In Burma the allies defeat the Japanese infantry for the first time.