This article focuses on the involvement of Siemens in the market for radiology equipment in Japan between 1900 and 1945. It explores why the German multinational company was unable to keep its dominant position in the Japanese market in the interwar years despite its technological competitiveness. At this time the Japanese medical market was already well structured when the country opened up to the West. In particular, it examines the firm's strategic choices in relation to the changing economic and technological environment, highlighting the importance for foreign multinationals of working together with national trading firms involved in the distribution of drugs and products for doctors.