2026.02.25
Practical Points to Note Regarding “Disclaimer”
PATENT
Practical Points to Note Regarding “Disclaimer”
1. Introduction
A “disclaimer” refers to a claim that explicitly states exclusion of only a part of matters included in the claimed invention from matters recited in the claim, while retaining the expression of the matters stated in the claim. In Japanese patent practice, “disclaimers” are often used in a manner where an applicant makes an amendment to form a “disclaimer” that excludes overlap with prior art cited during examination from the scope of claims, and then asserts novelty and inventive step of the invention of the application.
For example, Japanese Patent No. 7769825 specifies in Claim 1 “a fluoride ion removing agent comprising (A) a cerium compound and (B) a potassium compound (excluding alum) and/or a lithium compound, ...” During the examination of that patent, it was judged as follows: among the invention according to Claim 1 as originally filed, an embodiment in which alum is used as the potassium compound is described in a cited reference, and thus the invention lacks novelty. In response, the applicant made an amendment to add the wording “excluding alum” to exclude overlap with the cited reference from the scope of the claims, and argued in a written opinion that there were no grounds for refusal regarding novelty and inventive step based on that cited reference as the primary reference. As a result, the applicant overcame the refusal and received a decision to grant a patent.
With respect to “disclaimers,” issues may arise regarding (i) requirements for amendment, (ii) inventive step, and (iii) clarity. In this article, we analyze views of the Japan Patent Office (hereinafter, “JPO”) on each of these issues based on documents published by the JPO, and consider practical points to note in light of the views of the JPO.
2. Requirements for Amendment
(1) Practical Standard
An amendment to form a “disclaimer” is often made for the purpose of excluding a certain invention described in a reference cited during examination from the scope of claims. Since it is difficult to fully predict, at the time of filing, the references that will be cited during the examination, there are few cases where the specification, etc. as of the filing explicitly states that a certain scope of technical matters described in such references is to be excluded from the technical scope of the invention of the application. Therefore, for many amendments to form “disclaimers,” the matters to be excluded from the scope of the claims are not explicitly described in the specification, etc. as of the filing, and thus an issue arises regarding compliance with the requirements for amendment that prohibit the addition of a new matter.
Regarding whether an amendment to form a “disclaimer” complies with the requirements for amendment, the current practical standard is the holding of the Grand Panel Decision in the Solder Resist Case (Case No. 2006 (Gyo-ke) 10563, decision rendered on May 30, 2008 by the Intellectual Property High Court, Special Division). In that case, legality of a correction to form a “disclaimer” was at issue, because the exclusion of a specific technical matter from the scope of the claims was not explicitly described in the specification, etc. as of the filing. The key points of the standard derived from the decision of that case are as follows.
・ An amendment or a correction that does not introduce any new technical matter in relation to the technical matters derived by comprehensively considering all descriptions in the specification or the drawings can be deemed to be made “within the scope of the matters described in the specification or the drawings.”
・ Even an amendment or a correction involving a matter not specifically described in the specification or the drawings should be regarded as being made “within the scope of the matters described in the specification or the drawings,” as long as the amendment or the correction is recognized not to introduce any new technical matter in light of the technical matters disclosed by the specification or the drawings.
This standard is reflected in the “Examination Guidelines for Patent and Utility Model in Japan” and is referred to in the JPO examination practice. The quoted portion below is a portion revised following the Solder Resist Grand Panel Decision; however, the decision confirmed that the items (i) and (ii) in the quoted portion, which included description of the same gist even before the revision, did not set requirements for permitting amendments but merely provided examples of cases where amendments are permitted.
A “disclaimer” refers to a claim that explicitly states exclusion of only a part of matters included in the claimed invention from matters recited in the claim, while retaining the expression of the matters stated in the claim. In Japanese patent practice, “disclaimers” are often used in a manner where an applicant makes an amendment to form a “disclaimer” that excludes overlap with prior art cited during examination from the scope of claims, and then asserts novelty and inventive step of the invention of the application.
For example, Japanese Patent No. 7769825 specifies in Claim 1 “a fluoride ion removing agent comprising (A) a cerium compound and (B) a potassium compound (excluding alum) and/or a lithium compound, ...” During the examination of that patent, it was judged as follows: among the invention according to Claim 1 as originally filed, an embodiment in which alum is used as the potassium compound is described in a cited reference, and thus the invention lacks novelty. In response, the applicant made an amendment to add the wording “excluding alum” to exclude overlap with the cited reference from the scope of the claims, and argued in a written opinion that there were no grounds for refusal regarding novelty and inventive step based on that cited reference as the primary reference. As a result, the applicant overcame the refusal and received a decision to grant a patent.
With respect to “disclaimers,” issues may arise regarding (i) requirements for amendment, (ii) inventive step, and (iii) clarity. In this article, we analyze views of the Japan Patent Office (hereinafter, “JPO”) on each of these issues based on documents published by the JPO, and consider practical points to note in light of the views of the JPO.
2. Requirements for Amendment
(1) Practical Standard
An amendment to form a “disclaimer” is often made for the purpose of excluding a certain invention described in a reference cited during examination from the scope of claims. Since it is difficult to fully predict, at the time of filing, the references that will be cited during the examination, there are few cases where the specification, etc. as of the filing explicitly states that a certain scope of technical matters described in such references is to be excluded from the technical scope of the invention of the application. Therefore, for many amendments to form “disclaimers,” the matters to be excluded from the scope of the claims are not explicitly described in the specification, etc. as of the filing, and thus an issue arises regarding compliance with the requirements for amendment that prohibit the addition of a new matter.
Regarding whether an amendment to form a “disclaimer” complies with the requirements for amendment, the current practical standard is the holding of the Grand Panel Decision in the Solder Resist Case (Case No. 2006 (Gyo-ke) 10563, decision rendered on May 30, 2008 by the Intellectual Property High Court, Special Division). In that case, legality of a correction to form a “disclaimer” was at issue, because the exclusion of a specific technical matter from the scope of the claims was not explicitly described in the specification, etc. as of the filing. The key points of the standard derived from the decision of that case are as follows.
・ An amendment or a correction that does not introduce any new technical matter in relation to the technical matters derived by comprehensively considering all descriptions in the specification or the drawings can be deemed to be made “within the scope of the matters described in the specification or the drawings.”
・ Even an amendment or a correction involving a matter not specifically described in the specification or the drawings should be regarded as being made “within the scope of the matters described in the specification or the drawings,” as long as the amendment or the correction is recognized not to introduce any new technical matter in light of the technical matters disclosed by the specification or the drawings.
This standard is reflected in the “Examination Guidelines for Patent and Utility Model in Japan” and is referred to in the JPO examination practice. The quoted portion below is a portion revised following the Solder Resist Grand Panel Decision; however, the decision confirmed that the items (i) and (ii) in the quoted portion, which included description of the same gist even before the revision, did not set requirements for permitting amendments but merely provided examples of cases where amendments are permitted.
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(4) In the case of amendment which provides a disclaimer “Disclaimer” refers to claims explicitly stating exclusion of only part of matters included in the claimed inventions from matters stated in said claims, while leaving the expression of the statement of matters stated in the claims. “Disclaimer,” which excludes matters stated in the originally attached description, etc. through amendment while leaving the expression of the statement of matters stated in claims before amendment, is permitted if the “disclaimer” after exclusion does not introduce any new technical matter. The amendment to provide a “disclaimer” in the following (i) and (ii) does not introduce any new technical matter, and the amendment is permitted. (i) The amendment to exclude only the overlap in case where the claimed invention overlaps the cited invention and is thus likely to lose novelty, etc. (Article 29(1)(iii), Article 29bis or Article 39) <<Omitted>> (ii) In the case where the claimed invention includes the term “human being” and thus does not fulfill the requirement of the main paragraph of Article 29(1) of the Patent Act or falls under the category of unpatentable invention under Article 32 of the Patent Act, an amendment which excludes only the term “human being” <<Remainder omitted>>
(Excerpted from the Examination Guidelines for Patent and Utility Model in Japan,
Part IV, Chapter 2 “Amendment Adding New Matter”)
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(2) Recognition of Issues at the JPO
Regarding issues concerning the requirements for amendment in case of “disclaimers,” the JPO points out the following in a document titled “Regarding Amendments to Form ‘Disclaimer’” (Japanese version only) published on its website in April 2025.
・ Applicants are required, when making an amendment, to fully explain that the amendment falls within the scope of the matters described in the specification, etc. as originally filed.
・ In particular, when an applicant asserts that a refusal for lack of inventive step has been overcome by a “disclaimer,” there is a possibility that the invention according to the claim has changed from an invention of which the technical idea is not remarkably different from that of the cited invention to an invention of which the technical idea is remarkably different from that of the cited invention, and there exists a doubt that the amendment has introduced a new technical matter.
In relation to these issues, an Expert Committee of the JPO has pointed out that many cases are seen where the applicant merely explains that an amendment to form a “disclaimer” has excluded overlap with a cited reference, without fully explaining that the amendment falls within the scope of the matters described in the specification, etc. as originally filed. As one cause, the Expert Committee notes the possibility that the statement of the Examination Guidelines quoted above — “(i) The amendment to exclude only the overlap in case where the claimed invention overlaps the cited invention and is thus likely to lose novelty, etc. (Article 29(1)(iii), Article 29bis or Article 39)” — may have led to the misunderstanding that the requirements for amendment is satisfied as long as the amendment is to exclude only the overlap with the cited invention.
(3) Practical Points to Note
Given that the JPO has issued cautions regarding the requirements for amendment regarding “disclaimers” as noted above, when an applicant makes an amendment to form a “disclaimer,” it is desirable to provide a logical explanation on the compliance with the requirements for amendment.
In asserting that the requirements for amendment are satisfied, the holding in the Marine Vessel Case (Case No. 2021 (Gyo-ke) 10151, decision rendered on August 23, 2022 by the Intellectual Property High Court) is instructive. In that case, the issue was whether it was permissible to correct the statement “watertight compartment” in the claims to “watertight compartment (excluding a tank)” so as to exclude one which also serves as a tank. The court held that the correction was legal. The key points of the grounds supporting such a conclusion are as follows.
・ Since a “watertight compartment” may have a function of a tank, it is recognized that the “watertight compartment” includes those which also serve as tanks and those which do not. There is no reason for interpreting that the specification, etc. of the subject case as describing only watertight compartments which also serve as tanks. Accordingly, the specification, etc. of the subject case is recognized to disclose both “watertight compartment” which also serves as a tank and “watertight compartment” which does not serve as a tank. Therefore, it is clear that the exclusion of inventions including a “watertight compartment” which also serves as a tank does not introduce any new technical matter.
・ There is also no room to interpret that a new technical matter has been introduced by a change in the action and the effect of the invention due to the correction.
Following the decision of the Marine Vessel Case, it is effective to explain based on common technical knowledge, etc. that the descriptions of the specification, etc. as originally filed encompass both inventions including and not including the scope to be excluded by the “disclaimer.” In practice, we have experienced some cases where our clients asserted legality of amendments to form “disclaimers” based on the Marine Vessel Case in written opinions and then the amendments were accepted.
However, based on a contrario interpretation of the decision of the Marine Vessel Case, it is understood that, if circumstances such as a change in the action and the effect of the invention arise due to the amendment, it may be judged that the amendment has introduced a new technical matter. For example, if it is argued that a configuration excluding a part of matters achieves advantageous effects over a configuration not excluding them, this may introduce a new matter with regard to the technical significance of the configuration excluding the part of matters, and be judged as addition of a new matter. Accordingly, care is required in structuring logical arguments for inventive step.
It has also been confirmed that the statement of the Examination Guidelines — “(i) The amendment to exclude only the overlap in case where the claimed invention overlaps the cited invention and is thus likely to lose novelty, etc. (Article 29(1)(iii), Article 29bis or Article 39)” — provides an example, not a criterion, in a decision of a case where legality of a correction to form a “disclaimer” in an invention relating to a Freon gas composition was an issue (Case No. 2022 (Gyo-ke) 10125, decision rendered on October 5, 2023 by the Intellectual Property High Court). In that case, the “excluded” portion was specified by numerical limitation including a range overlapping with a prior application. The defendant argued as follows: the correction was not a legal correction complying with the (i) above in the Examination Guidelines, because the “excluded” portion was not limited to only the overlap with the cited invention. However, the court held that the above statement in the Examination Guidelines was not a requirement and found the correction legal because it did not introduce any new technical matter. Further, as seen in that case, it is also permissible to define the “excluded” scope by numerical limitations.
3. Inventive Step
(1) Recognition of Issues at the JPO
If the overlapping portion with a cited invention is excluded from the scope of the claims by an amendment to form a “disclaimer,” the invention to be examined is no longer identical to the cited invention, and thus a refusal for lack of novelty is overcome. On the other hand, if the amended invention is considered to be easily conceivable starting from the excluded portion, a refusal for lack of inventive step is not overcome.
In this regard, the JPO points out the following in “Regarding Amendments to Form ‘Disclaimer’” published in April 2025.
・ An invention that can be patented by using a “disclaimer” to overcome a refusal due to lack of novelty, etc. is one that, when compared with the cited invention identified in the grounds for refusal, is remarkably different in technical idea and thus originally has inventive step, but happens to overlap with the cited invention.
・ If the invention is not remarkably different in technical idea from the cited invention, it is believed that a refusal for lack of inventive step will rarely be overcome by using a “disclaimer.”
The Expert Committee of the JPO also has pointed out a gap between the views seen on the applicant’s side and the JPO’s view.
Regarding issues concerning the requirements for amendment in case of “disclaimers,” the JPO points out the following in a document titled “Regarding Amendments to Form ‘Disclaimer’” (Japanese version only) published on its website in April 2025.
・ Applicants are required, when making an amendment, to fully explain that the amendment falls within the scope of the matters described in the specification, etc. as originally filed.
・ In particular, when an applicant asserts that a refusal for lack of inventive step has been overcome by a “disclaimer,” there is a possibility that the invention according to the claim has changed from an invention of which the technical idea is not remarkably different from that of the cited invention to an invention of which the technical idea is remarkably different from that of the cited invention, and there exists a doubt that the amendment has introduced a new technical matter.
In relation to these issues, an Expert Committee of the JPO has pointed out that many cases are seen where the applicant merely explains that an amendment to form a “disclaimer” has excluded overlap with a cited reference, without fully explaining that the amendment falls within the scope of the matters described in the specification, etc. as originally filed. As one cause, the Expert Committee notes the possibility that the statement of the Examination Guidelines quoted above — “(i) The amendment to exclude only the overlap in case where the claimed invention overlaps the cited invention and is thus likely to lose novelty, etc. (Article 29(1)(iii), Article 29bis or Article 39)” — may have led to the misunderstanding that the requirements for amendment is satisfied as long as the amendment is to exclude only the overlap with the cited invention.
(3) Practical Points to Note
Given that the JPO has issued cautions regarding the requirements for amendment regarding “disclaimers” as noted above, when an applicant makes an amendment to form a “disclaimer,” it is desirable to provide a logical explanation on the compliance with the requirements for amendment.
In asserting that the requirements for amendment are satisfied, the holding in the Marine Vessel Case (Case No. 2021 (Gyo-ke) 10151, decision rendered on August 23, 2022 by the Intellectual Property High Court) is instructive. In that case, the issue was whether it was permissible to correct the statement “watertight compartment” in the claims to “watertight compartment (excluding a tank)” so as to exclude one which also serves as a tank. The court held that the correction was legal. The key points of the grounds supporting such a conclusion are as follows.
・ Since a “watertight compartment” may have a function of a tank, it is recognized that the “watertight compartment” includes those which also serve as tanks and those which do not. There is no reason for interpreting that the specification, etc. of the subject case as describing only watertight compartments which also serve as tanks. Accordingly, the specification, etc. of the subject case is recognized to disclose both “watertight compartment” which also serves as a tank and “watertight compartment” which does not serve as a tank. Therefore, it is clear that the exclusion of inventions including a “watertight compartment” which also serves as a tank does not introduce any new technical matter.
・ There is also no room to interpret that a new technical matter has been introduced by a change in the action and the effect of the invention due to the correction.
Following the decision of the Marine Vessel Case, it is effective to explain based on common technical knowledge, etc. that the descriptions of the specification, etc. as originally filed encompass both inventions including and not including the scope to be excluded by the “disclaimer.” In practice, we have experienced some cases where our clients asserted legality of amendments to form “disclaimers” based on the Marine Vessel Case in written opinions and then the amendments were accepted.
However, based on a contrario interpretation of the decision of the Marine Vessel Case, it is understood that, if circumstances such as a change in the action and the effect of the invention arise due to the amendment, it may be judged that the amendment has introduced a new technical matter. For example, if it is argued that a configuration excluding a part of matters achieves advantageous effects over a configuration not excluding them, this may introduce a new matter with regard to the technical significance of the configuration excluding the part of matters, and be judged as addition of a new matter. Accordingly, care is required in structuring logical arguments for inventive step.
It has also been confirmed that the statement of the Examination Guidelines — “(i) The amendment to exclude only the overlap in case where the claimed invention overlaps the cited invention and is thus likely to lose novelty, etc. (Article 29(1)(iii), Article 29bis or Article 39)” — provides an example, not a criterion, in a decision of a case where legality of a correction to form a “disclaimer” in an invention relating to a Freon gas composition was an issue (Case No. 2022 (Gyo-ke) 10125, decision rendered on October 5, 2023 by the Intellectual Property High Court). In that case, the “excluded” portion was specified by numerical limitation including a range overlapping with a prior application. The defendant argued as follows: the correction was not a legal correction complying with the (i) above in the Examination Guidelines, because the “excluded” portion was not limited to only the overlap with the cited invention. However, the court held that the above statement in the Examination Guidelines was not a requirement and found the correction legal because it did not introduce any new technical matter. Further, as seen in that case, it is also permissible to define the “excluded” scope by numerical limitations.
3. Inventive Step
(1) Recognition of Issues at the JPO
If the overlapping portion with a cited invention is excluded from the scope of the claims by an amendment to form a “disclaimer,” the invention to be examined is no longer identical to the cited invention, and thus a refusal for lack of novelty is overcome. On the other hand, if the amended invention is considered to be easily conceivable starting from the excluded portion, a refusal for lack of inventive step is not overcome.
In this regard, the JPO points out the following in “Regarding Amendments to Form ‘Disclaimer’” published in April 2025.
・ An invention that can be patented by using a “disclaimer” to overcome a refusal due to lack of novelty, etc. is one that, when compared with the cited invention identified in the grounds for refusal, is remarkably different in technical idea and thus originally has inventive step, but happens to overlap with the cited invention.
・ If the invention is not remarkably different in technical idea from the cited invention, it is believed that a refusal for lack of inventive step will rarely be overcome by using a “disclaimer.”
The Expert Committee of the JPO also has pointed out a gap between the views seen on the applicant’s side and the JPO’s view.
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(The views seen on the applicant’s side) As an argument by an applicant regarding inventive step of an invention after an amendment to form a “disclaimer,” it is sometimes asserted that, since an essential configuration of the cited invention has been excluded, it is recognized that there is a teaching away from arriving at the invention to be examined from the cited invention. This argument is based on the following idea: for the inventor of the cited invention, employing the configuration excluded by the amendment is the very point of the invention, and therefore no change to remove such a point would be made. |
(The JPO’s view) According to the approach in the Examination Guidelines, one should consider the matter from the standpoint of the relevant technical field upon viewing the cited invention while stepping back from the standpoint of the inventor of the cited invention. A third-party skilled person, in seeking further improvements, may through trial and error to solve problems different from those addressed by the cited invention, and easily conceive an invention including the configuration excluded by the amendment, starting from an invention not including such a configuration. Moreover, even if the configuration excluded by the amendment is an essential configuration of the cited invention, it may not necessarily constitute such a strong teaching away as to completely prevent replacement with any other configuration. |
(2) Practical Points to Note
In light of the above indication of the JPO, when asserting the inventive step of an invention after an amendment to form a “disclaimer,” it is necessary to structure arguments from a third-party perspective separate from the standpoint of the inventor of the cited invention. In other words, arguments based only on the essential configurations of the cited invention or on the problems to be solved by the cited invention itself may be insufficient, and it is desirable to consider from other perspective while stepping back from the cited invention.
In the previously mentioned Marine Vessel Case, determination was made on the inventive step of the invention after correcting the statement “watertight compartment” in the claims to “watertight compartment (excluding a tank)” so as to exclude one which also serves as a tank, and the inventive step of the invention after the correction was acknowledged. The key points of the grounds supporting such a conclusion are as follows.
・ The “anti-rolling tank” of the cited invention is recognized as a “watertight compartment” which also serves as a tank.
・ In the cited reference, there is no evidence that suggests configuration of a “watertight compartment” which also serves as a tank by separately configuring a tank and a “watertight compartment” which does not serve as a tank. Further, there is no evidence that suggests placement of a “watertight compartment” without a function of a tank at a location for a tank originally designed to exert the function of a tank and recognized to also have a function of a “watertight compartment,” while arranging a separate tank at a location different from that location. Accordingly, no motivation is found to replace the “anti-rolling tank” of the cited invention with space as a “watertight compartment.”
・ If the “anti-rolling tank” that serves as a tank were replaced with a “watertight compartment” without a function of a tank, additional layout space to house a tank would be required, and the location originally usable as a tank could no longer be used as a tank, which would reduce the design flexibility. Therefore, it is recognized that a teaching away exists against such replacement.
As seen above, in the Marine Vessel Case, the motivation to replace a “watertight compartment serving as a tank” in the cited invention with a “watertight compartment not serving as a tank” was assessed based on common technical knowledge in marine vessels, apart from the core concept of the cited invention. As in that case, it is considered to be effective to assert that an invention after an amendment is not easily conceivable based on issues related to differences in technical significance between inventions including and not including a configuration excluded by a “disclaimer.”
However, as noted in the section on the requirements for amendment, if circumstances such as a change in the action and the effect of the invention arise due to the amendment, it may be judged that the amendment has introduced a new technical matter. Accordingly, when making an amendment to form a “disclaimer,” arguments for inventive step based on the action and the effect of the invention after the amendment may be judged as addition of a new matter. Therefore, inventive step should be asserted based on differences in configuration between the invention after the amendment and the cited invention and on the lack of a logical basis for overcoming those differences.
4. Clarity
(1) Recognition of Issues at the JPO
The JPO requests, in the document “Regarding Amendments to Form ‘Disclaimer’” issued on April 2025, that applicants, etc. take care to avoid lack of clarity from the following viewpoints when making an amendment to form a “disclaimer.”
・ When the “excluded” portion occupies a large part of the claimed invention or extends to many items, it may become impossible to clearly grasp a single invention from a single claim.
・ When the “excluded” portion is described by borrowing expressions from a reference cited in a Notice of Reasons for Refusal, it may be impossible to clearly understand the content intended to be specified by that description unless the content of the reference is actually confirmed, even in light of the common technical knowledge as of the filing.
(2) Practical Points to Note
In light of the above cautions of the JPO, when making an amendment to form a “disclaimer,” attention should be paid to the following points.
・ The scope of the “excluded” portion should not be excessive.
・ The “excluded” portion should be described using objective expressions. For example, the “excluded” portion should be expressed by names or features of specific components, or by chemical compound names, etc.
5. Conclusion
An amendment to form a “disclaimer” is judged for compliance with the requirements for amendment based on the criterion of whether it introduces a new technical matter. As long as this criterion is satisfied, specification of the “excluded” scope is not restricted by the descriptions in the specification, etc. as originally filed. However, a careful explanation in a written opinion, etc. is required to show that the amendment does not introduce any new technical matter. In providing such an explanation, it is preferable to first specify the entire scope that is inherently encompassed by the specification, etc. as originally filed and then assert that the amendment merely excludes a part of that scope.
Regarding the inventive step of an invention after an amended to form a “disclaimer,” it is insufficient to argue that the invention to be examined is not conceivable only on the basis of the essential configurations or problems to be solved of the cited invention. It should be noted that arguments must be made from a third-party perspective separated from that of the inventor of the cited invention.
Regarding the clarity of a “disclaimer,” care should be taken so that the “excluded” scope does not become excessive, and the “excluded” scope should be specified in an objective manner.
In light of the above indication of the JPO, when asserting the inventive step of an invention after an amendment to form a “disclaimer,” it is necessary to structure arguments from a third-party perspective separate from the standpoint of the inventor of the cited invention. In other words, arguments based only on the essential configurations of the cited invention or on the problems to be solved by the cited invention itself may be insufficient, and it is desirable to consider from other perspective while stepping back from the cited invention.
In the previously mentioned Marine Vessel Case, determination was made on the inventive step of the invention after correcting the statement “watertight compartment” in the claims to “watertight compartment (excluding a tank)” so as to exclude one which also serves as a tank, and the inventive step of the invention after the correction was acknowledged. The key points of the grounds supporting such a conclusion are as follows.
・ The “anti-rolling tank” of the cited invention is recognized as a “watertight compartment” which also serves as a tank.
・ In the cited reference, there is no evidence that suggests configuration of a “watertight compartment” which also serves as a tank by separately configuring a tank and a “watertight compartment” which does not serve as a tank. Further, there is no evidence that suggests placement of a “watertight compartment” without a function of a tank at a location for a tank originally designed to exert the function of a tank and recognized to also have a function of a “watertight compartment,” while arranging a separate tank at a location different from that location. Accordingly, no motivation is found to replace the “anti-rolling tank” of the cited invention with space as a “watertight compartment.”
・ If the “anti-rolling tank” that serves as a tank were replaced with a “watertight compartment” without a function of a tank, additional layout space to house a tank would be required, and the location originally usable as a tank could no longer be used as a tank, which would reduce the design flexibility. Therefore, it is recognized that a teaching away exists against such replacement.
As seen above, in the Marine Vessel Case, the motivation to replace a “watertight compartment serving as a tank” in the cited invention with a “watertight compartment not serving as a tank” was assessed based on common technical knowledge in marine vessels, apart from the core concept of the cited invention. As in that case, it is considered to be effective to assert that an invention after an amendment is not easily conceivable based on issues related to differences in technical significance between inventions including and not including a configuration excluded by a “disclaimer.”
However, as noted in the section on the requirements for amendment, if circumstances such as a change in the action and the effect of the invention arise due to the amendment, it may be judged that the amendment has introduced a new technical matter. Accordingly, when making an amendment to form a “disclaimer,” arguments for inventive step based on the action and the effect of the invention after the amendment may be judged as addition of a new matter. Therefore, inventive step should be asserted based on differences in configuration between the invention after the amendment and the cited invention and on the lack of a logical basis for overcoming those differences.
4. Clarity
(1) Recognition of Issues at the JPO
The JPO requests, in the document “Regarding Amendments to Form ‘Disclaimer’” issued on April 2025, that applicants, etc. take care to avoid lack of clarity from the following viewpoints when making an amendment to form a “disclaimer.”
・ When the “excluded” portion occupies a large part of the claimed invention or extends to many items, it may become impossible to clearly grasp a single invention from a single claim.
・ When the “excluded” portion is described by borrowing expressions from a reference cited in a Notice of Reasons for Refusal, it may be impossible to clearly understand the content intended to be specified by that description unless the content of the reference is actually confirmed, even in light of the common technical knowledge as of the filing.
(2) Practical Points to Note
In light of the above cautions of the JPO, when making an amendment to form a “disclaimer,” attention should be paid to the following points.
・ The scope of the “excluded” portion should not be excessive.
・ The “excluded” portion should be described using objective expressions. For example, the “excluded” portion should be expressed by names or features of specific components, or by chemical compound names, etc.
5. Conclusion
An amendment to form a “disclaimer” is judged for compliance with the requirements for amendment based on the criterion of whether it introduces a new technical matter. As long as this criterion is satisfied, specification of the “excluded” scope is not restricted by the descriptions in the specification, etc. as originally filed. However, a careful explanation in a written opinion, etc. is required to show that the amendment does not introduce any new technical matter. In providing such an explanation, it is preferable to first specify the entire scope that is inherently encompassed by the specification, etc. as originally filed and then assert that the amendment merely excludes a part of that scope.
Regarding the inventive step of an invention after an amended to form a “disclaimer,” it is insufficient to argue that the invention to be examined is not conceivable only on the basis of the essential configurations or problems to be solved of the cited invention. It should be noted that arguments must be made from a third-party perspective separated from that of the inventor of the cited invention.
Regarding the clarity of a “disclaimer,” care should be taken so that the “excluded” scope does not become excessive, and the “excluded” scope should be specified in an objective manner.
6. References
(1) Regarding Amendments to Form “Disclaimer”
(JPO, April 2025)
(2) Industrial Structure Council, Intellectual Property Committee, Patent System Subcommittee, 18th Examination Guidelines Expert Committee Working Group Minutes Material 3
(JPO, November 17, 2025)
(3) Examination Guidelines for Patent and Utility Model in Japan, Part IV, Chapter 2
“Amendment Adding New Matter”(JPO)
(4) Grand Panel Decision in the Solder Resist Case
(Case No. 2006 (Gyo-ke) 10563, decision rendered on May 30, 2008 by the Intellectual Property High Court, Special Division)
(5) Marine Vessel Case decision
(Case No. 2021 (Gyo-ke) 10151, decision rendered on August 23, 2022 by the Intellectual Property High Court)
(6) Decision in the case of a composition including 2,3-dichloro-1,1,1-trifluoropropane, 2-chloro-1,1,1-trifluoropropene, 2-chloro-1,1,1,2-tetrafluoropropane, or 2,3,3,3-tetrafluoropropene
(Case No. 2022 (Gyo-ke) No.10125, decision rendered on October 5, 2023, Intellectual Property High Court)
(1) Regarding Amendments to Form “Disclaimer”
(JPO, April 2025)
(2) Industrial Structure Council, Intellectual Property Committee, Patent System Subcommittee, 18th Examination Guidelines Expert Committee Working Group Minutes Material 3
(JPO, November 17, 2025)
(3) Examination Guidelines for Patent and Utility Model in Japan, Part IV, Chapter 2
“Amendment Adding New Matter”(JPO)
(4) Grand Panel Decision in the Solder Resist Case
(Case No. 2006 (Gyo-ke) 10563, decision rendered on May 30, 2008 by the Intellectual Property High Court, Special Division)
(5) Marine Vessel Case decision
(Case No. 2021 (Gyo-ke) 10151, decision rendered on August 23, 2022 by the Intellectual Property High Court)
(6) Decision in the case of a composition including 2,3-dichloro-1,1,1-trifluoropropane, 2-chloro-1,1,1-trifluoropropene, 2-chloro-1,1,1,2-tetrafluoropropane, or 2,3,3,3-tetrafluoropropene
(Case No. 2022 (Gyo-ke) No.10125, decision rendered on October 5, 2023, Intellectual Property High Court)
