一序 　　日本民法典已经过了 100年。如果回顾这段民法学的历史就会发现，其研究的重点领域是随时代而变化的。在 20世纪 80至 90年代，契约法就曾经被作为最重要的问题领域受到广泛的关注，而且在这一过程中，还可以看到对以往被作为契约法存在的前提予以承认的一些基本框架 A Japanese Civil Code has been 100 years. If we review the history of civil law, we will find that the focus areas of its research change with the times. In the 1980s and 1990s, the law of contract was once widely regarded as the most important problem area. In the process, some basic frameworks, which have been recognized as preconditions of contract law in the past, can also be seen