The Japan Patent Office (JPO) revised its Examination Guidelines for Patent and Utility Model, with the revised guidelines applying to examinations conducted on or after July 1, 2026.
The revisions cover a number of areas of Japanese patent examination. Among them, three changes are particularly relevant to overseas applicants and patent practitioners: the treatment of disclaimer claims, the assessment of inventive step, and the handling of divisional applications based on foreign-language written applications.
1. Revised Guidance on Disclaimer Claims
One of the most notable revisions concerns amendments using so-called “disclaimer claims.”
A disclaimer claim excludes a particular part of the originally claimed subject matter while leaving the basic wording of the claim in place. Such amendments are sometimes used in response to a novelty or inventive-step rejection, particularly where an applicant seeks to exclude subject matter disclosed in cited prior art.
The JPO has clarified that an amendment introducing a disclaimer is not automatically regarded as complying with the prohibition against adding new matter merely because the amendment excludes an overlap with the cited prior art. As with other amendments, whether a disclaimer introduces new matter must be assessed in light of the disclosure of the application as originally filed.
The JPO has also added new guidance to its Examination Handbook concerning the examination of applications containing disclaimer claims.
For applicants, this means that disclaimers may remain a useful prosecution tool, but their wording and basis in the original disclosure should be considered carefully when responding to an Office Action.
2. Clarification of Inventive-Step Analysis
The revised guidelines also clarify the treatment of “obstructive factors” in the assessment of inventive step.
Under Japanese examination practice, an examiner considering whether a claimed invention could have been easily made does not look only at reasons for combining the teachings of different prior-art references. Factors that would discourage or prevent a skilled person from making such a combination may also be relevant.
For example, an obstructive factor may exist where applying the teaching of a secondary reference to the primary reference would be contrary to the purpose of the primary invention or would prevent it from functioning as intended.
The 2026 revision clarifies the discussion of these factors in the Examination Guidelines. This is relevant not only to examiners but also to applicants preparing arguments against inventive-step rejections. Where an Office Action relies on a combination of multiple references, applicants should consider whether the proposed combination is technically natural and whether there are reasons why a skilled person would have avoided it.
3. Divisional Applications Based on Foreign-Language Written Applications
The JPO has also clarified the handling of substantive requirements for divisional applications and related applications where the original application is a foreign-language written application.
Japan allows certain patent applications to be initially filed in a foreign language, with a Japanese translation subsequently submitted. This system is frequently relevant to overseas applicants.
When a divisional application is filed from such an application, particular attention is required as to whether the divisional application satisfies the substantive requirements for a valid division and whether the claimed subject matter is properly supported by the relevant application documents.
The revised guidelines provide clearer guidance on how these requirements should be examined where the original application was filed as a foreign-language written application.
For overseas applicants, the clarification is a useful reminder that the relationship between the original foreign-language documents, the Japanese translation, and the subject matter of a later divisional application should be carefully considered when planning a divisional filing strategy in Japan.
Practical Implications for Overseas Applicants
The July 2026 revisions do not represent a wholesale change in Japanese patent law. Rather, many of the revisions clarify how existing requirements should be applied in examination practice.
Nevertheless, the three areas discussed above can have practical consequences during prosecution. Applicants considering disclaimer amendments, responding to inventive-step rejections based on combinations of prior art, or filing divisional applications from foreign-language written applications should take the revised guidance into account.
For further details, please see the Japan Patent Office’s official announcement on the revision of the Examination Guidelines.
