Introduction

Japan changed considerably during the decade of the 1950s, and research in science and technology was no exception in this regard. World War II came to an end in August 1945 with the surrender of Japan, which in 1950 was still under occupation by the allied powers. The economic situation was miserable: Inflation was rampant, black markets were thriving, and people were literally starving. However, the morale of theoretical physicists was high, for during the 1940s they had produced the two-meson theory, the super-many-time theory, and the covariant renormalization theory. In 1949, Hideki Yukawa was honored with the Nobel Prize in physics. In contrast to this flourishing theoretical culture, the level of experimental particle and nuclear physics was very depressed. For example, on 23 November 1945, all the cyclotrons in Japan – two at the Institute for Physical and Chemical Research (Riken) in Tokyo, one at Osaka University, and one under construction at Kyoto University – were dismantled by order of the occupation forces, who threw the dismembered parts into the sea (possibly also into a lake). On 30 January 1947, the Far Eastern Committee, which was the organization for policy making of the allied powers in Japan, decided that “all research in Japan of either a fundamental or applied nature in the field of atomic energy should be prohibited.” This prohibition, which obviously put severe restrictions on the resumption of research in nuclear physics, was in force until the peace treaty became effective in 1952.

Over the ten years after the signing of the peace treaty in 1952, by which Japan recovered its independence, economic conditions improved significantly.