Japanese Gold Standard for Added Matter and Its Similarity with G2/21 (Plausibility)

Abstract In common with many jurisdictions worldwide, in Japan a patent application or a patent may not be amended in such a way that it contains subject matter that extends beyond the content of the specification as originally filed, i.e., added subject matter (or new matter). However, the method of determining the boundary between allowable and unallowable amendments is unique in Japan, and the Japanese approach is arguably one of the most generous among all major jurisdictions. If a scale is drawn ranging from a ‘photographic’ level at one end (where literal support for an amendment must always be found in the original application) to an ‘impressionistic’ level at the other (where literal support for an amendment does not play any role at all), the Japanese standard is perhaps closer to the latter. This article firstly aims to serve as a practical guide into this unique practice for international users. As the author believes that the rationale behind the Japanese standard regarding the allowability of amendments shares many things in common with the standard given in G2/21 (i.e., the EPO’s Enlarged Board of Appeal decision regarding a reliance on a purported technical effect for inventive step), the rest of this article then strives to provide a unique approach to interpret the G2/21’s standard, while comparing it with the Japanese added matter standard.