Legal transplants and change: Unjust enrichment law in Japan

The dissertation is a comparative study of the Roman, French and German origins of the Japanese law of unjust enrichment and the modifications Japan imposed on the transplanted legal rules. It demonstrates that Japan has not altered the Greek natural law philosophy or the core Roman formulation of the legal rules that form the basis of all civil law unjust enrichment actions. Initially, because the Japanese code is primarily German in form and content (although the dissertation identifies a definite French influence), Japan uniformly accepted German legal doctrine. However, the Japanese legal system in time modified the formulation and application of certain fundamental German rules in order to achieve socially acceptable results.; The dissertation reviews the Roman unjust enrichment actions (condictiones), the judicial recognition of the doctrine in France, the codification of the action in Germany, and directly links each system and their legal rules to the Japanese codes; first the 1890 Boissonade draft, and then the current code. The dissertation also evaluates pre-code Tokugawa customary law, and concludes that although there was some indica of unjust enrichment consciousness, it was insufficient to effect the transplanted legal rules.; The focus of the dissertation is an analysis of Japanese unjust enrichment law, focusing on the differences between the Japanese and German interpretation of the legal rules, utilizing the most prominent Japanese academic commentators and case law. The dissertation demonstrates that Japan accepted the basic elements of the unjust enrichment action without alteration: a transfer of economic value (including labor as well as property) without legal cause that resulted in a loss to one party and a gain to another. The Japanese legal system rejected the German requirement that the transfer had to be direct, and adopted a "social common sense" standard because, as the commentators observed, that while the German rule resulted in strict justice, in certain indirect enrichment cases it failed to achieve substantive justice.