Li Yibin Liu Yang

Abstract:［Purpose /Significance］Since 2020，the interaction between the "Five Eyes Alliance" and Japan has increased significantly,and there are obvious differences in the discussion about whether Japan will join the alliance.The exploration of the logic of the expansion of the "Five Eyes Alliance" can help answer this question．

［Method /Process］Starting from the history of the expansion of the "Five Eyes Alliance"，the expansion structure is summarized as a pyramid type，from top to bottom: the United States，"Five Eyes" "Nine Eyes"" Fourteen Eyes" and " 5+1" or " 5+X" mode.Through combing the history and structure,the logic of its expansion is further explored．

［Result /Conclusion］According to the alliance theory,the basic logic of the " Five Eyes Alliance" expansion is to chase power，and the specific logic is: the United States leads，seeks out specific opponents，and limits the scale．According to this logic，we explored the issue of Japan’s accession to the alliance，and found that the reasons behind it include American interests and strategic needs，as well as China’s being regarded as a core opponent．Further research shows that Japan cannot truly integrate into the " Five Eyes Alliance".However，the"Five Eyes Alliance"’s expansion of personnel against China deserves our attention and vigilance．

Key words: Five Eyes Alliance; Japan; expansion logic; alliance theory; China－US relations