The parent company, Weaver Pharmaceutical, had extensive international operations and was one of the largest U.S. drug firms. Its competitive position depended heavily on research and development (R&D). Sales activity in Japan started in the early 1930s when Yamazaki Pharmaceutical, a major producer of drugs and chemicals in Japan, began distributing Weaver's products. World War II disrupted sales, but Weaver resumed exporting to Japan in 1948 and subsequently captured a substantial market share. To prepare for increasingly keen competition from Japanese producers, Weaver and Yamazaki established in 1954 a jointly owned and operated manufacturing subsidiary to produce part of Weaver's product line.
Through the combined effort of both parent companies, the subsidiary soon began manufacturing sufficiently broad lines of products to fill the general demands of the Japanese market. Imports from the United States were limited to highly specialized items. The company conducted substantial R&D on its own, coordinated through a joint committee representing both Weaver and Yamazaki to avoid unnecessary duplication of efforts. The subsidiary turned out many new products, some of which were marketed successfully in the United States and elsewhere. Weaver's management considered the Japanese operation to be one of its most successful international ventures and felt that the company's future prospects were promising, especially given the steady improvement in Japan's standard of living.
The subsidiary was headed by Shozo Suzuki who, as executive vice president of Yamazaki and president of several other subsidiaries, limited his participation in Weaver-Yamazaki