The Committee on Cataloging of Japan Library Association has published the Nippon Cataloging Rules, 2018 Edition(NCR2018) in December 2018, which is a new cataloging code for libraries in Japan. One of its features is the compatibility with the Resource Description and Access(RDA). The purpose of this study is to depict the characteristics of NCR2018 through a comparison with RDA. First, this study reveals the following four causes for the differences between NCR2018 and RDA: 1) the use of Japanese language and characters, 2) the use of an alternative heading system, 3) the use of a bibliographic hierarchical structure, and 4) the code is for cataloging Japanese publications. Second, the study examines why these differences are necessary for Japan, or why Japan could not directly adopt RDA. This study also identifies the difficulties that libraries in Japan will face when adopting NCR2018.