Both the European Patent Office (EPO) and the Japanese Patent Office (JPO) accept a third party observation regarding validity of a patent application. In February 2012, it was announced that third party observations could be filed for Patent Cooperation Treaty (PCT) applications as well. And while the timing may be different for these jurisdictions, the goal and content of these submissions remain consistent. Care must be taken however because while there are advantages with these submissions, the disadvantages may outweigh them in some cases.


Following publication of the European patent application under Article 93, any person may present observations concerning the patentability of the invention. An attractive feature in some cases is that third party observations can be filed anonymously. Although lack of novelty and/or inventive step are the most common observations, third party observations may also be directed to clarity (Art. 84), sufficiency of disclosure (Art. 83), patentability (Art. 52(2) and (3), 53 or 57), and unallowable amendments (Art. 76(1), 123(2) and 123(3)).[1] Observations must be filed in either English, French, or German and contain a statement of the grounds on which they are based.

Following submission, the party that files the observations is effectively removed from any proceedings regarding the observations, meaning the EPO does not inform them of any further action it takes in response to the submission. Observations are communicated to the Applicant/Patentee and they have the opportunity to comment on the submission, but the submitting party is not provided any specific notice.

Once substantiated by the EPO, they will generally issue an office action within three months of receipt by the examining division.

China and Japan

The State Intellectual Property Office (SIPO) in China and the JPO accept third party observations by any party. In Japan, a third party can submit at any time after a patent application or an application for utility model registration is filed, even after a decision is made to grant a patent or utility model registration. However, in China, third party observations (also known as public observations) are only allowed for invention patent applications. The SIPO is also stricter with their requirements for the third party observations.

With respect to the reasons for refusal or invalidation, the JPO accepts observations related to the following provisions:[2]

  • Article 17bis, Paragraph 3 (Addition of New Matter);
  • Body Text of Article 29, Paragraph 1 (Patentable Subject Matter or Lack of Industrial Applicability);
  • Article 29, Paragraph 1 (Lack of Novelty);
  • Article 29, Paragraph 2 (Lack of Inventive Step);
  • Article 29bis (Secret Prior Art);
  • Article 39, Paragraphs 1 to 4 (Prior Application / Double Patenting);
  • Article 36, Paragraph 4, Item 1 (Violation of Enablement Requirement);
  • Article 36, Paragraph 6, Items 1 to 3 (Violation of Description Requirement for Claims); and
  • Article 36bis, Paragraph 2 (Addition of New Matter as to the Original Text).

With respect to the submission to the JPO, it must be filed in writing, and supporting evidence, such as copies of publications or certifying documents (such as experimental reports), may be submitted.

In China, there is no criteria for the submission. And while the third party can act anonymously, the Chinese examiner will not respond to any submission of prior art, but may take it into account during substantive examination.

PCT applications

Third party observations are also allowable, through ePCT, for published PCT applications. Any third party (even anonymously) may submit only one observation any time after the date of publication and before expiration of 28 months from the priority date, provided the application is not withdrawn or considered withdrawn.[3] Following submission, the patent applicant is notified and provided the opportunity to comment on the observations at any time up to expiration of 30 months from the priority date. To the extent that the observations are received by any competent International Searching Authority and/or the International Preliminary Examining Authority in time to be taken into account in preparing their respective reports, any prior art referred to in the observations will be considered, provided that either a copy of the prior art is included, or it is otherwise immediately available to the examiner. The observations will also be transmitted to the designated Offices promptly after the expiration of 30 months from the priority date. The designated Offices are, however, not obliged to take them into account during national processing.


As mentioned in the companion article, third party observations are a cost-effective opportunity for any third party to submit relevant art or arguments (often anonymously) to an examining jurisdiction. In Europe, a pre-grant third party observation may be the only opportunity to raise objections with respect to clarity and unity. Since these submissions bring prior art to the attention of the patent applicant, the applicant must inform any foreign jurisdiction of the existence of that art in any jurisdiction where there is a duty to disclose relevant art.

On the flip side, the third party submitter has no participation in the examination process once the submission is filed. If the examiner ignores the submitted references or the patent applicant can overcome a rejection based on the submitted references, the resulting patent may actually be harder to invalidate. Therefore, the pros and cons of each submission must be weighed before moving forward.


This article appeared in the September 2018 issue of Global Patent Prosecution Newsletter.