In Japan, three-dimensional trademarks are sometimes registered in recognition of their original distinctiveness, but most of them are registered by acquiring the distinctiveness by use under the Japanese Trademark Act. Looking at cases in Japan, even if a registered design has been worked for a long time, it is not determined that trademark registration can be unconditionally obtained in recognition of the distinctiveness by use of the shape of the design. In Japan, due to the above circumstances, it can be seen that the three-dimensional shape itself is somewhat difficult to obtain trademark registration. According to the recently revised Examination Guidelines for Trademarks of the Japanese Patent Office, recognizing that a trademark does not deviate from the scope of the product’s shape itself is not distinctive, and it is also treated as the same when the trademark is recog nized as part of the shape of the product itself. Here, it is worth noting that if a three-dimensional shape is recognized as being adopted for the purpose of contributing to the function or aesthetics of the product, it is determined that it does not deviate from the scope of the product shape itself. The Japanese Patent Office’s Examination Guidelines for Trademarks deal with the criteria for determining the identity of the applied trademark and the used trademark in determining acquired distinctiveness by use, which will also need to be referred to in Korea. In particular, it is worth noting that acquired distinctiveness by use can be recognized if the applied trademark part is independently recognized as a mark used to distinguish goods of one business from those of others, although marks other than the applied trademark are included among the used trademarks. On the other hand, the Japanese Patent Office’s Trademark Examination Manual shows more specific standards and related cases than Examination Guidelines for Trademarks for determining the distinctiveness of three-dimensional trademarks. In this Manual, the same criteria as the standards for determining the distinctiveness of flat trademarks are applied to the overall distinctiveness of three-dimensional trademarks combined with letters, and the criteria for determining when the entire letter or figure is not displayed on the three-dimensional trademark are also specifically stated. In addition, the Trademark Examination Manual deals with the identity of the applied trademark and the used trademark in determining acquired distinctiveness by use in very detail. In other words, it reveals that even if letters or figures are attached to a three-dimensional shape, acquired distinctiveness by use can be recognized, and If the applied trademark uses the distinction between solid and broken lines, it is explained in detail that in principle, the mark part (solid line) of the applied trademark is compared with the used trademark without considering the part (broken line) that does not constitute the trademark in the determination of identity. According to the Trademark Examination Manual, it is worth noting that the Japanese Patent Office somewhat broadly recognizes the identity of the applied trademark and the used trademark in determining acquired distinctiveness by use. On the other hand, it can be seen that the degree of freedom or replacement of the three-dimensional shape for each product plays an important role in the determination of the original distinctiveness. According to the trend of Japanese court’s decisions, it can be seen that three-dimensional trademarks combined with letter trademarks have become easier in recognition of distinctiveness and the possibility of trademark registration has increased after the Coca-Cola bottle case. In this paper, the legal principles of representative decisions related to Article 3 (1) 3 of the Japanese Trademark Act are reviewed, and it is necessary to pay attention to the legal principles of related decisions.