head of the Navy General Staff's Planning section, on the grounds that the United States was likely to use Australia as a base to launch a counter-offensive in the South-West Pacific. The Navy headquarters argued that this invasion could be carried out by a small landing force as this area of Australia was lightly defended and isolated from Australia's main population centres. There was not universal support for this proposal within the Navy, however, and Isoroku Yamamoto, the commander of the Combined Fleet, consistently opposed it. The Japanese Army opposed the Navy's proposal as being impractical. The Army's focus was on defending the perimeter of Japan's conquests, and it believed that invading Australia would over-extend these defence lines. Moreover, the Army was not willing to release the large number of troops it calculated was needed for such an operation from the Kwantung Army in Manchuria as it both feared that the Soviet Union would enter the Pacific War and wanted to preserve an option for Japan to invade Siberia. Prime Minister Hideki Tojo also consistently opposed invading Australia. Instead, Tojo favoured a policy of forcing Australia to submit by cutting its lines of communication with the US. In his last interview before being executed for war crimes Tojo stated, In speeches before the Diet of Japan on 12 January and 16 February 1942, Tojo claimed Japanese policy was to "eradicate the British colonies at Hong Kong and in the Malay Peninsula as these were 'evil bases used against East Asia', and turn these places into strongholds for the defence of Greater East Asia. Burma and the Philippines would get independence if they co-operated with Japan; the Netherlands East Indies and Australia would be crushed if they resisted; but if they recognised Japan's true intentions would receive help in promoting their welfare and development." The Army's and the Navy's calculations of the number of troops needed to invade Australia differed greatly and formed a central area of discussion. In December 1941 the Navy calculated that a force of three divisions (between 45,000 and 60,000 men) would be sufficient to secure Australia's north-eastern and north-western coastal areas. In contrast, the Army calculated that a force of at least ten divisions (between 150,000 and 250,000 men) would be needed. The Army's planners estimated that transporting this force to Australia would require 1.5 to 2 million tons of shipping, which would have required delaying