While US-China tensions have been rising due to technology, Japan-China relations have improved. Japan highly considers the importance of Japan-US security, but cannot ignore its economic relations with China. Japan-US-China relations stand at a great turning point. As technology involves both security and economics, it is not possible to resolve the situation if politics is separated from economics. How then have Japan-China relations been developed? Firstly, China-Japan relations in the context of the current competition between China and the United States is discussed. Secondly, two points are examined: (i) What kind of conditions did Japan present to China for Japan-China cooperation to proceed in spite of the current competition between China and the United States? (ii) How do they relate to and affect the Free and Open Indo-Pacific Strategy as well as the Belt and Road Initiative? Thirdly, future Japanese policy on China under further severe competition between China and the United States is considered.