Regarding so-called “disclaimer claims” (i.e., claims containing a negative limitation), the Grand Panel’s decision in the Solder Resist Case (2006 (Gyo-Ke) No. 10563–Intellectual Property (IP) High Court, May 30, 2008) established a criterion for determining their validity. This ruling addressed the phrase “within the scope of the matters described in the specification or drawings” under Article 17(2) of the Patent Act prior to the 1994 amendment (currently Article 17-2(3)) and defined a criterion for the meaning of “the matters described in the specification or drawings” as the technical matters derived from a comprehensive review of all descriptions in the specification or drawings by a person skilled in the art. Consequently, an amendment that does not introduce any new technical matter in relation to the technical matters derived from such a review qualifies as an amendment made “within the scope of the matters described in the specification or drawings.”

 

The Grand Panel further held that amendments to claims Involving a disclaimer (hereinafter, also referred to as disclaimer amendments) likewise should be assessed based on this criterion—specifically, whether the amendment introduces any new technical matter in relation to the technical matters described in the specification, etc.—and that there is no room for assuming “exceptional” treatment for such amendments.

 

Following the finalization of this Grand Panel decision, the JPO revised the Examination Guidelines for “Amendments of Description, Claims or Drawings (New Matter)” in June 2010.

 

 

 

The Patent Committee, Second Division of the Japan Patent Attorneys Association (JPAA) evaluated the utility of disclaimer claims and presented its findings in the report dated March 9, 2023.

 

In an article summarizing this report and titled “Evaluation of the Utility of Disclaimer Claims” (Patent, Vol. 77, No. 6, pp. 45–60 (2024)), it is concluded that disclaimer claims are useful as a means of amendment to overcome the reason for refusal based on lack of Inventive Step not only in the chemical technology field but also in non-chemical fields such as electrical, mechanical, and software technologies, based on the results of the analysis of patents registered in fiscal year 2021 and containing disclaimer claims.

 

In particular, the article points out that excluding an element essential for solving the problem of the cited invention from the claimed invention creates a situation requiring the deliberate omission of the essential element of the cited invention to reach the claimed invention. The article presents the findings that it is effective to make such a disclaimer amendment to overcome the reason for refusal based on lack of Inventive Step, and to assert in Written Argument that the cited invention teaches away from modifying it to exclude the essential element.

 

 

 

While the usefulness of disclaimer claims is recognized, concerns about their abuse are also rising alongside their increased use.

 

Disclaimer claims are often viewed as not constituting Addition of New Matter, and they allow the original claim scope to be maintained more broadly than if the claims were progressively narrowed by adding language disclosed in the specification, etc. as filed. Consequently, these claims appear to have been used frequently, particularly since the Grand Panel’s decision mentioned above. Considering such circumstances, there is a view that disclaimer amendments should not always be approved even to overcome a reason for refusal, etc.; that the extent of exclusion must be reasonable; and that the Inventive Step after a disclaimer amendment also must be appropriately assessed１.

 

If exclusion of claimed matter broader than the overlapping scope with prior art is approved, the applicant (patentee) can take the content of prior art into consideration to exclude a scope broader than descriptions in the prior art and assert the Inventive Step of the claimed invention, even though the excluded matter was not disclosed at the time of filing the application. For a third party’s perspective, this makes it impossible to predict the nature of future amendments (corrections). Consequently, there is a view that a restriction should be imposed on disclaimer amendments—those excluding recitations not disclosed in the specification, etc. as filed—to limit the extent of exclusion only to the scope overlapping with the cited invention２.

 

The JPO’s “Report from Trial and Appeal Practitioners’ Working Group 2023” (March 2024) also mentions that many participants expressed concerns about the current situation where use of disclaimer claims is excessively permissive; the use is approved not only in cases of establishing Novelty over “accidental prior art.” The report notes an opinion to the JPO that whether the prior art used for the original reason for refusal still negates the Novelty and/or Inventive Step should be carefully considered even after a disclaimer amendment has been made.

 

1 Shimao Kato, “Disclaimer Amendments: Proposals for Appropriate Examination and Trial That Do Not Allow Gaining Unfair Advantages through Disclaimer,” in Professor Setsu Shimizu’s 70th Birthday Commemorative Collection, Toward the Future of Diversifying Intellectual Property Litigation, Nihon Kajo Publishing (October 2023)

2 Setsuko Asami, “The Ideal Form of ‘Disclaimer Claims’ – Using the Fluorine Compound Composition Case as a Case Study,” Intellectual Property Management, Vol. 75, No. 1, 2025, pp. 5–18

 

 

 

 

There are recent cases where the IP High Court did not accept applicants’ arguments for Inventive Step based on disclaimer claims.

 

 

In the Enzyme-Treated Milk Product Case (2024 (Gyo-Ke) No. 10012–IP High Court, October 30, 2024), the Inventive Step of the disclaimer claim—“bovine milk (excluding bovine colostrum)”—was contested against the primary cited invention that uses “bovine colostrum.” The Plaintiff (Applicant) argued that the reason bovine colostrum is selected in the invention of Exhibit A-1 (primary cited invention) lies in the fact that it contains a high concentration of Gc-globulin, and that there is thus no motivation in the invention of Exhibit A-1 to substitute bovine colostrum with bovine mature milk, which has a lower Gc-globulin concentration; on the contrary there is teaching away from doing so.

 

However, the IP High Court judged from the following reasons that there is sufficient motivation to apply the technical matter of Exhibit A-3 to the invention of Exhibit A-1 and adopt “bovine milk (excluding bovine colostrum)” in place of “bovine colostrum” of the invention of Exhibit A-1, and that no teaching away is found.

 

・Exhibit A-3 discloses “dairy products, colostrum, or fermented culture fluid” as sources of Gc-globulin. In addition, Exhibits A-4, A-5, and Exhibits B-5 and B-6 demonstrate that bovine milk being a source of Gc-globulin is well-known technical knowledge prior to the priority date of the subject application.

・Although bovine colostrum has a relatively high Gc-globulin concentration among other types of bovine milk, it is considered a material with a low Gc-globulin concentration compared to blood-derived materials, such as serum or plasma.

・No description is found in Exhibit A-1 that would constitute teaching away for adopting bovine milk other than bovine colostrum.

 

This judgment is noteworthy for clarifying that the mere exclusion of an essential element of a cited invention does not automatically establish teaching away, and that obviousness should be substantively assessed from the perspective of a person skilled in the art. This judgement approach is in line with the JPO’s guidelines to be described below.

 

 

 

In April 2025, the JPO’s Examination Guidelines Office published a document titled “Amendments to Claims Involving a Disclaimer”. This document clearly outlines the points for applicants to consider when making disclaimer amendments, with a strong focus on the following three points:

 

 

Regarding Inventive Step, the document clearly states that when the technical idea of the claimed invention does not significantly differ from that of the cited invention, making a disclaimer amendment rarely overcomes the reason for refusal based on lack of Inventive Step. This point clarifies the limitations of disclaimer claims in light of the situations where disclaimer claims are used to establish not only Novelty but also Inventive Step.

 

The document further points out regarding Addition of New Matter that there is a question as to whether a new technical matter has been introduced through the disclaimer amendment. This is because when the applicant asserts that the disclaimer claim has overcome the reason for refusal based on lack of Inventive Step, there is a possibility that the technical idea of the claimed invention has changed from a state not significantly different from that of the cited invention to a state significantly different. For this reason, applicants are required to explain in Written Argument, etc. that the technical idea has not been changed due to the amendment and that the claimed invention possesses Inventive Step even before the amendment.

 

Finally, the document points out regarding Clarity the potential lack of Clarity when the excluded matter constitutes a substantial part of the claimed invention; comprises numerous elements; or is recited using the language lifted from the prior art cited in the Notice of Reason(s) for Refusal.

 

 

 

The series of developments outlined above indicates an industry-wide movement seeking the proper use of disclaimer claims. An increased number of cases is anticipated where disclaimer claims will be more cautiously and stringently assessed in future examination practices and trial and appeal practices at the JPO, as well as IP High Court judgements.

 

Under such circumstances, strategies that excessively rely on a disclaimer claim should be reconsidered in future patent practices. Disclaimer claims should be positioned as a means of an amendment to avoid overlapping scope with accidental prior art.

 

For an invention not significantly different from the technical idea of the cited invention, the simplistic strategy of excluding the essential element of the cited invention and asserting the Inventive Step is likely to become untenable in future examination practices, trial and appeal practices, and court practices.
Conversely, when an invention significantly different from the technical idea of the cited invention formally lacks Novelty, excluding the cited invention to clarify the scope of the claimed invention is a legitimate practice. In other words, the issue is not the disclaimer claim itself, but the perception that Inventive Step is easily established by employing a disclaimer claim.

 

 

 

This article has outlined recent developments associated with disclaimer claims: a renewed recognition of their utility, rising concerns about their potential abuse, and a shift toward emphasizing substantive assessment, and the publication of administrative guidelines. These developments indicate a movement toward institutional reform, repositioning disclaimer claims as a means to avoid accidental prior art, which is their original intended purpose. I believe that it is possible to contribute to the sound development of the entire Japanese patent system by gaining practical experiences in accordance with the system’s intent, while closely monitoring future developments in examination practices and trial and appeal practices, as well as judicial precedents.

 

 

Edited by Kenshi Takenaka