Japanese researchers who initiated fusion research were of the common view that “fusion research should start from basic research.” However, the A-plan (“developing and realizing new ideas”) and the B-plan (“building medium-sized devices”) proposed in March 1959 by Kakuyugo Senmonbukai (the Special Panel on Nuclear Fusion Research, established in 1958) of the Japan Atomic Energy Commission under the auspices of the Prime Ministerʼs Office took a different view from the above-mentioned common view. These future plans led to an intense dispute that in later years was referred to as the A-B plans dispute. A particular focus of the A-B plans dispute was the B-planʼs aim of building in Japan the type of medium-sized devices that had obtained some success in foreign countries. Many previous studies have emphasized the influence of the second United Nations International Conference on the Peaceful Uses of Atomic Energy (September, 1958) on Senmonbukaiʼs drafting of the B-plan; but in addition to this, domestic arguments also had a strong influence, such arguments arising from the results of questionnaires that Kakuyugo Kondankai (Nuclear Fusion Research Group) had carried out about how to proceed with nuclear fusion research, and the insistence of some researchers, especially experimentalists, that the B-plan should be carried out as “basic research of engineering.” At first, many Senmonbukai members approved the implementation of the B-plan. However, Kakuyugo Kenkyu-iinkai (the B-plan committee) did not resolve a type of the B-plan device. Therefore, some Senmonbukai members changed an opinion and didnʼt agree with the B-plan. Subsequently, the B-plan was postponed.
