In early 1942, as the list of military defeats and reversals for the Australian, British, American and Dutch military and naval forces began to mount, the feeling in the general populace of Australia was one of depression and a general expectation that the Japanese would invade at any moment. Almost as if aware of these fears, the Japanese were, by April 1942, examining the possibility of capturing Port Moresby, Tulagi, New Caledonia, Fiji and Samoa. The object of this plan was to extend and strengthen the Japanese defensive perimeter as well as cutting the lines of communication between Australia and the United States. The occupation of Port Moresby, designated Operation MO, would not only cut off the eastern sea approaches to Darwin but provide the Imperial Japanese Navy with a secure operating base on Australia's northern doorstep.
While the Japanese Naval General Staff were examining options for further operations the planning staff of the Japanese Combined Fleet were doing the same, though their objectives were different. In early April 1942 the staff of the Combined Fleet had presented the Naval General Staff with a proposal for the invasion and capture of Midway Island. By this action it was hoped that the American Fleet would be enticed “into an ambush where they [the American Fleet] could be annihilated by overwhelming numbers”. In essence Admiral Isoroku Yamamoto was hoping to repeat Admiral Togo Heihachiro’s victory over the Russians at the Straits of Tsushima in 1905. After much haggling the two staffs agreed to go ahead with the Midway operation after the capture of Port Moresby. However, planning progressed slowly until 18 April when American B25 bombers, led by Lieutenant Colonel James H Doolittle, attacked targets in the Japanese Home Islands.
