This article analyzes the development of the concept of informed consent in the context of the culture and economics of Japanese medicine, and locates that development within the framework of the nation's civil law system. Part II sketches the cultural foundations of medical paternalism in Japan; explores the economic incentives (many of them administratively directed) that have sustained physicians' traditional dominant roles; and describes the judiciary's hesitancy to challenge physicians' professional discretion. Part III delineates the forces testing the paternalist model: the undermining of the physicians' personal knowledge of their patients that accompanies the shift from neighborhood clinic to high-tech hospital medicine; the increasing sophistication of consumers of medical services, and their appetite for medical information; the rise of medical quality control issues, and patients' rights groups; and the influence of the movement for transparency, or openness in decisionmaking, in Japanese society as a whole. In particular, the article stresses the importance of two critical developments in focusing attention on informed consent: the debate over brain death and organ transplantation, and the enforcement by the Ministry of Health and Welfare of 'good clinical practice' rules governing clinical trials of investigational drugs.