This article focuses on the development of the Japanese medical instrument industry from the 1880s to the beginning of the war against China (1937). It argues that the growth of this industry relied on the adaptation of Western technologies to the Japanese environment. The article focuses on the learning processes adopted by Japanese entrepreneurs, revealing a major difference between small enterprises, engaged in innovation based on reverse engineering and cooperation with medical doctors, on the one hand, and large firms which benefitted from organisational facilities acquired through international technology transfer and cooperation with domestic R&D centres, on the other hand.