Abstract: “Work” is an indispensable bibliographic entity to achieve the objectives of catalogue proposed in international cataloguing principle. The definition of “work” in NCR1987 is confined at the conceptual level, which makes it hard to identify a work accurately. In contrast, NCR2018 takes RDA, which is based on FRBR, as reference to complete its conceptual definition of “work”. In addition, by introducing “authorized access point representing a work” from RDA, NCR2018 assigns “work” a clear
operational definition that helps to identify a work accurately.

Key words: Work, Nippon Cataloging Rules, NCR1987, NCR2018