Japan had to try and take out the US early on. The US would not stand for the New Greater East Asia Co-Prosperity Sphere. Thus, the reason for the Pearl Harbor attack. Once the US decided to go onto a total war footing it was just a matter of time before the Japanese were beaten back. Due to the immense resources of the USA. Japan did however quickly take a very large Asian – Pacific empire. Which meant the US and allies weren’t going to defeat Japan overnight. At 1st the Japanese had superior planes more experienced soldiers, pilots and the going was rough. However by the battle of Midway it was proven that the carriers would be the deciding factor in the Pacific war and the US had a distinct advantage in carriers from Midway on. Later the US developed superior deck top aircraft as well (i.e. the Corsair). The US out produced and outnumbered the Japanese. The war was prolonged however in a brutal island hopping campaign due to the dedication of both the Japanese soldier (even in the face of obvious defeat) and the steadfastness of the US army and marines. By 43 the air and sea battles were all allied victories such as the great Mariana’s Turkey Shoot which could be called the death kneel of the Japanese air force. From here a bloody war of attrition finally drove the Japanese back, cutting off all vital supplies and slowly destroying their armed forces.