The National Diet Library (NDL) is the sole national library in Japan. This poster mainly presents the National Diet Library Dublin Core Metadata Description (DC-NDL), which is a descriptive metadata standard utilized primarily for converting catalog records of publications held by the NDL into metadata based on the Dublin Core Metadata Element Set (DCMES) and the DCMI Metadata Terms. The key functions of the DC-NDL are the follows: (1) Representing the yomi (pronunciation), one of the characteristics of the Japanese language, (2) Connectivity with Linked Data especially for URI, and (3) Compatibility with digitized materials. Furthermore, we describe an example of implementing DC-NDL for use with NDL Search. To conclude, we point out issues for future research on the DC-NDL.