On June 16, 1958, Japan concluded the bilateral agreement with the United States which described the cooperaztion in the field of civlilian use of nuclear energy. This agreement became a cornerstone for the bilateral cooperation in the field of civilian use of nuclear energy that has continued until today. However, very few people knows that Japan and the United Kingdom concluded the almost same agreement on the same day.

This paper focuses on these two bilateral agreements and examines why and how were those agreements were concluded at the same day. Especially this research tries to consider the questions from the perspectives of the UK's and Japan's diplomatic strategy.

In this research, I hypothesizes that the original motive of concluding the agreement for both of UK and Japan were to compete agaisnt the US made regiolnal order in the East Asia after the World War II. To verify this hypothesis, this research examines the diplomatic records of the UK and Japan.