Episode 37

In this installment, I will explain partial designs and the determination of their similarity.
Traditionally, an "article" was defined as a tangible object circulating in the marketplace; parts of an article that could not be traded independently were not treated as "articles" under the Design Act, and designs pertaining to parts of an article were not eligible for protection.
However, there was an increase in "clever" imitations—where the overall design avoided infringement while incorporating a creative and distinctive part—making it impossible to adequately protect the investment involved. Consequently, the 1998 amendment expanded the scope of protection to include designs pertaining to parts of an article (*Commentary on Industrial Property Laws, Article by Article*).
Regarding the similarity of such partial designs, the courts have ruled as follows:
The partial design system aims to protect a registered partial design when the design of the specific part is identical or similar to that of another design, even if the overall shape of the article (indicated by broken lines) differs. Therefore, when determining the similarity of partial designs, one must ensure that differences in the position (or similar attributes) of the registered part versus the corresponding part do not defeat the purpose of the partial design system. Differences in position that can be interpreted as anticipated—such as changes in position within a reasonably conceivable range, viewed in light of the shape of the broken-line sections and the content of the partial design—do not affect the determination of similarity (IP High Court Judgment, January 31, 2007; Case No. 2006 (Gyo-Ke) 10317).
For cases involving similarity where the principal design is a "whole design" (design for the entire article) and the application for a related design is a "partial design," the IP High Court judgment of May 29, 2025 (Case No. 2024 (Gyo-Ke) 10108) serves as a useful reference. This lawsuit seeks the rescission of an appeal decision (Appeal No. 2023-19811) upholding a refusal of registration based on Article 3, Paragraph 1, Item 3 of the Design Act.
The design of the present application consists of a so-called flange portion—a part of the article (a packaging container)—whereas the cited design (the registered design at issue) encompasses the entire article (a storage container); thus, the two differ significantly in terms of "use, function, position, size, and scope," as well as shape. Consequently, the design of the present application cannot be considered similar to the cited design and is ineligible for registration as a related design under Article 10, Paragraph 1 of the Design Act.
Furthermore, since the design of the present application cannot be registered as a related design, the cited design (the registered design at issue) is not subject to the application of Article 10, Paragraph 2 of the Design Act; therefore, the cited design cannot be deemed not to fall under Article 3, Paragraph 1, Item 1 or 2 of the Act. The articles associated with the design of the present application and the cited design are a "packaging container" and a "storage container," respectively, sharing common uses and functions. Additionally, the relevant portions of both designs consist of a flange located on the left and right sides of the article, extending from the upper third of the outer edge to the top of the article; they share characteristic features—such as the shape of the flange's upper end, the appearance of the flange in a side view, and a pronounced indentation following a raised section at the flange's lower end—indicating a similarity in shape. Accordingly, the design of the present application is considered similar to the cited design (or the relevant portion thereof) and is ineligible for design registration pursuant to Article 3, Paragraph 1, Item 3 of the Act.
When comparing a "principal design" (which is a design for the whole article) with a "related design" that is a partial design, the comparison involves the entire principal design versus the specific part of the design for which registration is sought. In contrast, when comparing the design for which registration is sought with a cited design (a publicly known design), a lack of novelty (under Article 3, Paragraph 1, Items 1–3 of the Design Act) is recognized if even a portion of the cited design is identical or similar; thus, the comparison involves the design for which registration is sought versus a part (the cited portion) of the cited design. Consequently, when one design is a partial design and the other is a design for the whole article (whether a cited design or a principal design), the scope of comparison differs depending on whether one is determining the similarity between a principal design and a related design (which is a partial design) or determining the similarity (regarding novelty, etc.) between the design for which registration is sought and a cited design.
Based on the above, as a general rule, it is not permissible to register a design for the whole article as a principal design and a partial design thereof as a related design.
In the case of patents, the relationship between earlier and later applications is determined by comparing the inventions described in the respective claims; however, regarding novelty and similar requirements, the comparison is made between the invention described in the claims of the application in question and the entirety of the published earlier application (including its specification). A similar approach applies to designs.