Following the opening of the London Conference on 21 January 1930, there was growing concern in Tokyo over the difficulties being encountered in negotiations, especially between the Japanese and American delegations in London. There was also evidence of a major split within the Japanese delegation between the diplomats and the naval specialists.1 The naval specialists adhered very strictly to the ‘Three Principles’ and were opposed to any ‘political’ or ‘diplomatic’ solution to cope with the problem of American intransigence. Not surprisingly, since there were a variety of communication channels from London to Tokyo, both official and unofficial, the naval leaders in Tokyo were in touch with developments there. Nevertheless, the decision by the civilian delegates at London, to proceed with negotiations without full discussion with the navy specialists and even without the full knowledge of Plenipotentiary Takarabe, were a clear intimation of the determination of the civilians to reach an agreement. The exclusion of navy men in London from the decision-making process relating to an AmericanJapanese compromise, meant that the only information filtering through to the Navy in Tokyo was rather negative in character. This simply increased the speculation and fears of naval officers in Tokyo who were becoming more anxious lest the ‘Three Principles’ be the problems even for navy moderates who would have preferred that Japan’s ‘minimum’ conditions at London be met in full. But for Katō Kanji, who had come to believe that even the fulfilment of the Three Principles’ was inadequate, intelligence from London indicated that even these minimum demands would not be met. This clearly caused him very great concern that he believed necessitated prompt action.