a) According to the European Patent Convention, lack of clarity (Article 84 EPC) is not a ground for opposition against a European Patent (see Article 100 EPC).   However, according to Article 101(3) EPC, the Opposition Division must examine amendments made by the patent proprietor during the opposition proceedings with respect to “the requirements of the European Patent Convention”. Case law has interpreted this provision as meaning that amended claims filed by a patent proprietor in opposition proceedings must also be sufficiently clear (Art. 84 EPC).   This interpretation is based in particular on decision G9/91 by the Enlarged Board of Appeal. This decision states that, in case of amendments of the claims or other parts of a patent in the course of first or second instance opposition proceedings, such amendments are to be fully examined as to their compatibility with the requirements of the European Patent Convention.   But decision G9/91 does not explain exactly what is to be understood as an “amendment” of the patent. Consequently, some Boards of Appeal have considered that the introduction of the features of a granted dependent claim into an independent claim is not an “amendment” and thus that the resultant new independent claim cannot be examined as to its clarity. Other Boards of Appeal have qualified such a falling back to a granted dependent claim as an “amendment”, which needs to be in line with the clarity requirement.   b) This question of the extent to which an Opposition Division or a Board of Appeal is allowed to examine the clarity of claims amended during the Opposition proceedings was recently raised anew in case T0373/12.    In this case, the patent proprietor filed, during the appeal proceedings, an auxiliary request with an independent claim corresponding to the combination of claims 1 and 3 of the granted patent. Claim 3 of the patent recited the following additional feature: “the prosthetic liner is coated over substantially all of its surface area”.   The Opponent argued that this auxiliary request should be refused for non-compliance with Article 84 EPC (lack of clarity) because the feature “the prosthetic liner is coated over substantially all of its surface area” was unclear due to the use of the word “substantially”.   c) Considering that the Jurisprudence of the Boards of Appeal was not uniform on the matter as to whether features in an independent claim which have been taken literally from a granted dependent claim and inserted into the independent claim should be examined as to clarity (Article 84) in opposition proceedings, the Board of Appeal now referred the following questions to the Enlarged Board of Appeal:   1. Is the term "amendments" as used in decision G9/91 of the Enlarged Board of Appeal (see point 3.2.1) to be understood as encompassing a literal insertion of (a) elements of dependent claims as granted and/or (b) complete dependent claims as granted into an independent claim, so that opposition divisions and boards of appeal are required by Article 101(3) EPC always to examine the clarity of independent claims thus amended during the proceedings?   2. If the Enlarged Board answers Question 1 in the affirmative, is then an examination of the clarity of the independent claim in such cases limited to the inserted features, or may it extend to features already contained in the unamended independent claim?   3. If the Enlarged Board answers Question 1 in the negative, is then an examination of the clarity of independent claims thus amended always excluded?   These questions will be considered by the Enlarged Board of Appeal under the reference G3/14.   Written statements regarding this case can be filed at the European Patent Office until the end of August 2014.   We will keep you informed on any developments regarding this case.   If you have any questions, please contact Anne FRANCASTEL at afrancastel@lavoix.eu. 