Author: Alessandro Cossu
  1. The decision G 1/24 of the Enlarged Boards of Appeal, issued on 18 June 2025, was one of the most eagerly awaited decisions of the last years in the field of European patent law, as it concerned the hotly debated issue of whether the description and the drawings of a patent application (or a patent) should be used for interpreting the claims, when the patentability of the claimed invention is assessed under Articles 52 to 57 EPC. 
  1. In the following, an analysis of G 1/24 is presented together with an outline of the possible consequences of the decision on the practice of the Boards of Appeal and of the first-instance departments of the EPO; practical advice is also presented at the end. 
  1. All the opinions expressed in this commentary are the author’s personal views only. 
  1. Before analysing the decision G 1/24, it is useful to recall the three questions of law that were referred to the Enlarged Board of Appeal. 
  1. The first question asked whether Article 69(1), second sentence, EPC and Article 1 of the Protocol on the Interpretation of Article 69 EPC are to be applied to the interpretation of patent claims when assessing the patentability of an invention under Articles 52 to 57 EPC. 
  1. The answer of the Enlarged Board to the first question is that Article 69(1), second sentence, EPC and Article 1 of the Protocol on the Interpretation of Article 69 EPC are not to be applied in the examination of the patentability of the claims of an invention. 
  1. The second question asked whether the description and figures may be consulted when interpreting the claims to assess patentability and, if so, whether this may be done generally or only if the person skilled in the art finds a claim to be unclear or ambiguous when read in isolation. 
  1. The Board’s answer to this question is that the description and any drawings are always referred to when interpreting the claims, and not just in the case of unclarity or ambiguity. 
  1. The third question, asking whether a definition or similar information on a term used in the claims which is explicitly given in the description may be disregarded when interpreting the claims to assess patentability and, if so, under what conditions, was found to be inadmissible. 
  1. While the admissibility of the first and second questions was convincingly justified by the Enlarged Board, the reasoning in support of the finding of inadmissibility of the third question appears to be less clear and persuasive: in particular, it is not apparent why the Enlarged Board said that an answer to the third question was «not necessary» for the referring board, to reach a decision in the case before it. 
  1. The reason is that, at point II of the summary of facts and submissions of G 1/24, the Enlarged Board of Appeal noted that «a key issue in the appeal was whether claim 1 of the patent as granted was novel» and then recalled, at point III, that novelty of the claim hinged on whether the definition of the term «gathered sheet» given in the description was to be applied: it does therefore appear that an answer to the third question was actually necessary for the referring board, to decide on the issue of novelty. 
  1. It may be speculated that the Enlarged Board consciously chose not to engage with the third question, in order to leave the Boards of Appeal the necessary discretion – in each individual case – to decide how to specifically deal with definitions contained in the description, when interpreting the claims. At any rate, by not admitting the third question the Enlarged Board refrained from deciding whether a patent application or a patent can be generally used as its own dictionary for interpreting the claims.  
  1. Turning to the reasoning underlying the answer to the first question, the Enlarged Board first recalled that it is undisputed that the departments of the EPO, in the course of their duties, are required to interpret patent claims, when assessing the patentability of an invention. The Board then noted that the first question «concerns the legal basis in the EPC for carrying out this interpretation» and explained that «the two positions on this question are that the legal basis in the EPC is either Article 69 EPC and Article 1 of the Protocol on the interpretation of Article 69 EPC (“the Protocol”), or Article 84 EPC.». 
  1. These statements amount to an implicit reformulation of the first question, because the enquiry of the referring board formally concerned only Article 69 EPC in combination with Article 1 of its Protocol and did not mention Article 84 EPC. 
  1. After a very brief mention of previous decisions of the Boards of Appeal that relied either on Article 69 EPC (G 2/88 and G 6/88) or Article 84 EPC (G 2/12) as the legal basis for claim interpretation, the Enlarged Board of Appeal rejected both articles as an appropriate basis, noting that neither provision is «entirely satisfactory». 
  1. The Board’s reasoning for rejecting Article 69 EPC as a legal basis and, in fact, for answering the first question is persuasive and appears to have been reached by considering Article 69 EPC from a grammatical, systematic, teleological and historical point of view, in accordance with the principles of interpretation of treaties laid down in Articles 31 and 32 of the Vienna Convention on the Law of Treaties. 
  1. The reasoning for rejecting Article 84 EPC as an appropriate legal basis for claim construction, on the contrary, is not entirely persuasive. 
  1. The Enlarged Board’s remarks that Article 84 EPC «provides no guidance on how to interpret claims» and «only sets out an instruction to the drafter of what needs to be in the claims, and an instruction to the EPO to determine whether the claims meet that purpose» are understandable and, in principle, sufficient to conclude that Article 84 EPC is not an appropriate legal basis for claim construction.  
  1. It is instead not entirely understandable why the Enlarged Board felt compelled to say that Article 84 EPC «is formal in nature» and does not mention the invention.  
  1. It is beyond dispute in the case law of the Boards that «the matter for which protection is sought» of Article 84 EPC is, in the wider context of the Convention, quite simply the «invention» referred to in Articles 52 to 57 EPC (cf. T 56/21, reasons, point 13, last sentence): hence, while it is formally true that Article 84 EPC «does not mention the invention», the provision may arguably be understood to refer to the invention. 
  1. Furthermore, the requirement enshrined in the first sentence of Article 84 EPC seems to be more than a purely formal requirement, since it assigns the claims the substantive function of defining the invention whose patentability is to be assessed and of enabling the determination of the substantive rights of the patent owner in the designated Contracting States.  
  1. It is also noted that the Enlarged Board’s reasoning for rejecting Article 84 EPC falls short of considering the purpose of that provision in the system of the EPC, in contrast to the reasoning for rejecting Article 69 EPC.  
  1. As regards the second question, the Enlarged Board of Appeal noted that, despite the lack of a clear legal basis in the EPC, principles of claim construction can be extracted from an existing body of case law. 
  1. What is puzzling is that this body of case law relies on Article 69 EPC or Article 84 EPC, to derive applicable principles of claim interpretation: in other words, the case law referred to by the Enlarged Board of Appeal relies on those two provisions which the very same Enlarged Board considers unfit for providing a clear legal basis: as a consequence, it is not clear at all on which legal basis the two principles of claim construction identified at subsequent point 12 of G 1/24 would rest. 
  1. Arguably, the first principle identified – «the claims are the starting point and the basis for assessing the patentability of an invention under Articles 52 to 57 EPC» – is nothing more than the principle of primacy of the claims, which is a settled point in the case law of the Boards of Appeal and which undisputedly flows from Article 84, first sentence, EPC, although the Enlarged Board did not acknowledge this expressly. 
  1. The justification for the second principle identified at point 12 is, instead, much less clear. According to this principle, the description and any drawings are always referred to when interpreting the claims, and not just in the case of unclarity or ambiguity. 
  1. The first argument presented by the Enlarged Board in support of this principle is that interpreting the claims by referring to the description and drawings only in cases of unclarity or ambiguity «is contrary to the wording, and hence the principles, of Article 69 EPC». 
  1. This argument is patently at odds with the findings at point 7 of the reasons of G 1/24, where the Enlarged Board concluded that «Article 69 EPC and the Protocol are arguably only concerned with infringement actions before national courts and the UPC» and thus not applicable in the assessment of patentability. 
  1. The second argument is that interpreting the claims, when assessing their patentability, by referring to the description and the drawings only in cases of unclarity or ambiguity, as suggested in one line of case law of the Boards that is now rejected, «is also contrary to the practice of the national courts of the EPC states and to the practice of the UPC». 
  1. This argument is solely based on a policy choice, namely the goal of harmonisation of patent law in Europe. However, this goal hardly seems to be a cogent reason, in the absence of any legal reason within the EPC, for rejecting one approach to claim construction that has emerged in the case law of the Boards, arguably by applying the EPC: it cannot be understood why the Boards of Appeal, in the application of the EPC, should defer to national courts and the UPC, without there being a clear legal reason in the EPC for rejecting said one line of case law. 
  1. The third argument appears to suggest that the line of case law which considers it unnecessary to consult the description and drawings, when interpreting the claims, if the claims are clear and unambiguous, would be logically flawed, because it would allegedly fail to recognise that finding that «the language of a claim is clear and unambiguous is an act of interpretation, not a preliminary stage to such an interpretative act». 
  1. This argument, which purports to be one of logic, appears – on a closer look to be logically flawed. 
  1. Deciding that a claim is clear and unambiguous is undisputedly an act of interpretation, because it presupposes that the meaning of the claim has been singled out and identified with certainty. However, patent claims are addressed to the skilled person, who is supposed to have the technical background and a knowledge of the terminology ordinarily used in the relevant technical field: hence, the skilled person is normally capable of reading the claims and singling out their technical meaning without having to consult the description and the drawings.  
  1. Implying that any act of interpretation of the claims logically requires the consultation of the description and the drawings is as baseless as claiming that an English speaker would always need to consult a dictionary of the English language, in order to understand any utterance in English: it is plainly evident that an English speaker would have to consult a dictionary only if the utterance contained unknown words or words used with a particular meaning that does not accord with their generally recognised meaning. Other than in such special cases, any English speaker is normally capable of understanding an English sentence purely on the basis of his ordinary knowledge of the English language, without having to consult an English dictionary. 
  1. In summary, the only understandable reason in support of the second principle appears to be the goal of harmonising the practice of the EPO with the practice of the national courts and the UPC, rather than a legal reason derivable from within the EPC. The remarks at point 19 of the reasons of G 1/24, suggesting that the answers given to questions 1 and 2 are consistent with the case law of the Court of Appeal of the UPC, apparently confirm this finding. 
  1. However, a comparison of the order of the decision G 2/14 with the headnote 2 of the order of the Court of Appeal of the UPC of 26 February 2024 in the matter Nanostring Technologies vs 10x Genomics, as rectified by the order of 11 March 2024, reveals a significant difference. 
  1. Whereas the order of G 2/14 stipulates that «the description and drawings shall always be consulted to interpret the claims when assessing the patentability of an invention […], and not only if the person skilled in the art finds a claim to be unclear or ambiguous when read in isolation», headnote 2 of the order of the Court of Appeal of the UPC in its English translation instead requires that «the description and the drawings must always be used as explanatory aids for the interpretation of the patent claim and not only to resolve any ambiguities in the patent claim.» (emphasis added). 
  1. The order of decision G 2/14 does not provide any guidance on how the description and drawings should be consulted or referred to and does not prescribe that the description and drawings should be used «as explanatory aids»: the difference in language with the order of the Court of Appeal of the UPC is significant. 
  1. Furthermore, by expressly indicating that principles of claim construction already exist in the case law of the Boards of Appeal and need not be invented from scratch, the Enlarged Board of Appeal appears to have implicitly affirmed, in G 1/24, that the principles developed by the Boards of Appeal over the course of the years on the use of the description and drawings to interpret the claims continue to retain validity. 
  1. All this suggests that, while proclaiming the importance of aligning the practice of the EPO with that of the national courts and the UPC, the Enlarged Board of Appeal has in fact left the departments of the EPO free to continue to apply their own principles of claim construction. 
  1. Of particular interest, in this respect, is the remark in the second sentence at point 20 of the reasons, according to which «the correct response to any unclarity in a claim is amendment». The language used in this remark closely mirrors the language used in the decision T 1279/04, where – in the context of a discussion of claim interpretation in examination and opposition proceedings, i.e., in the assessment of the patentability of the claims – the deciding board stated:  

«Amendment rather than protracted argument should be the answer to genuine difficulties of interpretation in all aspects of the examination and opposition procedure». 

  1. The remark at point 20 of the reasons of G 1/24 thus seems to be meant as guidance on how the description should be used, whenever misalignment between the meaning of a term as used in the claims and its meaning as specified in the description creates unclarity: amendment of the claims (whenever possible), rather than arguing that the claims should be understood on the basis of definitions in the description, is the correct approach.  
  1. Considering that the Enlarged Board seems to have deliberately chosen not to answer the third question, the remark at point 20 of the reasons might furthermore be understood as an indication that the Board did not consider the theory of a patent being its own dictionary as being generally valid.  
  1. On the basis of these considerations and in view of the explicit reference to the existing principles of claim construction at point 10 of the reasons, it may be expected that the decision G 1/24 will not significantly change the practice of the Boards of Appeal, when it comes to the interpretation of claims for assessing their patentability. 
  1. It is worthwhile emphasising that the Boards of Appeal – even in the line of case law which G 1/24 has now rejected – have generally «referred to» the description and drawings, when interpreting the claims.  
  1. There is also no dispute that the Boards of Appeal have consistently considered the claims – and the claims only – as the starting point and basis for assessing the patentability of an invention, regardless of whether they considered recourse to the description and drawings as being allowable for interpreting the claims. 
  1. There also seems to be general consensus, in the case law of the Boards of Appeal, that restrictive features only disclosed in the description cannot be normally read into the claims to narrow their ambit, when the explicit wording of the claims does not recite such restrictive features, as this approach would deprive the claims of their intended function. 
  1. However, reference in G 1/24 to the principles of claim interpretation developed by the Boards might be invoked by some Boards to continue to apply the theory of the patent being its own dictionary: hence, it cannot be excluded that the case law of the Boards will continue to show a certain degree of divergence, in this respect. 
  1. The first decisions where the Boards of Appeal have applied the principles of G 1/24 suggest that G 1/24 has indeed not changed the practice of claim interpretation of the Boards of Appeal. 
  1. The decision T 1999/23, for example, expressly noted that G 1/24, while clarifying that the description has to be consulted when interpreting the claims, has otherwise indicated that principles of claim construction developed by the Boards are still applicable.  
  1. The board that decided the case T 1999/23 pointed out that one of these applicable principles stipulates that a narrower definition of a term in the description cannot be used to limit claimed subject matter that is clearly broader for the skilled person and explained the rationale behind this principle: a patent proprietor should not be allowed, in the formulation of the matter which third parties should not be allowed to use, to deviate without justification from the established terminology in a technical field, while drawing attention to this deviation in the description only; tolerating this practice unrestrictedly would undercut legal security (s. T 1999/23, reasons, no. 5.6). 
  1. A similar view has been held by the Boards in the decisions T 400/23, T 1846/23, T 1561/23 and T 161/24.
  1. As regards the practice at first instance, the EPO has already provided guidance to examiners on how to apply G 1/24, in the form of a so-called Practice and Procedure Notice (PPN) 2/25.  
  1. PPN 2/25 essentially instructs examiners to continue to apply the existing practices prescribed in the Guidelines and illustrates the procedure to be followed during the search and in the subsequent examination of two exemplary scenarios: one where the claim is narrower than the description and another one where the claim is broader. 
  1. In both scenarios, examiners are instructed to raise an objection under Article 84 EPC because of the inconsistency between the claim and the description and to ask the applicant to remove the inconsistency by way of amendment. 
  1. In principle, the instructions given in PPN 2/25 should entail that G 1/24 will have no impact on the practice of examining and opposition divisions; in practice, the situation may be expected to be more nuanced at first instance. 
  1. The increase of pressure on the examiners to grant European patents as quickly as possible has arguably led to a deterioration of the quality of examination at the EPO1, for example in the the notoriously time-consuming assessment of clarity, and to an increasing divergence between first-instance decisions and decisions of the Boards of Appeal2. 
  1. While most of the EPO examiners certainly do a very good job, despite the increasing production pressure on them, there is a risk that some of them might be lured to think, on the basis of the order of G 1/24, that terms in the claims having a broad and well-accepted meaning in the relevant technical field should to be interpreted in a narrower sense, in the light of a limiting definition contained in the description. Some examiners might thus be convinced, by reference to the authority of G 1/24, that such claims should be deemed novel over prior art that actually anticipates the feature in its broader meaning. 
  1. It is thus not unreasonable to expect that, in the second scenario where a term in a claim has a broader meaning than a limiting definition of that term contained in the description only, more applicants than in the past will now attempt ,at first instance, to reply to objections of lack of novelty based on prior art that anticipates the broader claim by arguing that the claim is novel in the light of the limiting definition in the description, in cases where the wording of the claim does not recite such a limitation, and that they would do so by citing the authority of G 1/24. 
  1. While most of the EPO examiners may be expected to follow the instructions given in PPN 2/25 (soon to be incorporated into the Guidelines) and to generally reject such attempts, some examiners might react differently.  
  1. Examiners under production pressure or with less experience might cave in and buy into the argument that the claim should be read as including a narrower definition found in the description only, thereby concluding that the unamended claim is novel, in spite of prior art anticipating the claim in its broader interpretation.  
  1. Other examiners might instead stick to a novelty objection and object to the lack of clarity, as required by PPN 2/25, thereby forcing applicants to amend the claims by incorporating the narrower definition contained in the description, and then raise an objection under Article 123(2) EPC, for example by arguing that further features of the passage that contains the definition should be included in the amended claims, to avoid an unallowable intermediate generalisation. 
  1. Although the order of G 1/24 only refers to the interpretation of the claims when assessing their patentability under Articles 52 and 57 EPC and thus – formally – does not apply to the assessment of the compliance of amendments with the requirements of Article 123 EPC, in particular those of Article 123(2) EPC, it is legitimate to ask whether the findings of G 1/24 should be applicable to the assessment of compliance with Article 123(2) EPC, since the application of the so-called gold standard (s. G 2/10, reasons, no 4.3) for examining amendments very often gives rise to issues of interpretation of the claims, when amendments of the claims are based on the description and/or the drawings. 
  1. It cannot be excluded that G 1/24 might be invoked by applicants or patentees for justifying an amendment, in a manner similar to that discussed above in connection with the second scenario mentioned in PPN 2/25, for example by arguing that a claim which has been amended in such a way that its wording clearly also encompasses an undisclosed technical realisation should be read, in the light of G 1/24, as only encompassing technical realisations disclosed in the description as filed.  
  1. Such arguments might for example be submitted by practitioners familiar with the case law of the Federal Court of Justice of Germany (BGH) on the interpretation of patent claims (s., in particular, the decisions X ZR 103/13, Kreuzgestänge, and X ZR 35/11, Zugriffsrechte). 
  1. It remains to be seen how the Boards of Appeal will react to such arguments, if raised, and whether the Boards will extend the applicability of the principles of G 1/24 to the examination of Article 123(2) EPC. 
  1. As regards claim interpretation for the assessment of the patentability of the claims, the following conclusions may be drawn. 
  1. The answers given by the Enlarged Board in the referral G 1/24, while apparently aligning the practice of the EPO in the interpretation of claims for assessing their patentability with the practice of national court and the UPC, are sufficiently ambiguous to give the departments of the EPO the discretion to continue to apply the existing principles of claim construction developed by the Boards over the years. 
  1. In particular, it it appears that the principle of primacy of the claims has been reaffirmed and the first decisions of the Board of Appeal applying the principles of G 1/24 suggest that the practice of claim interpretation at the EPO is not about to be turned on its head; it remains to be seen whether examining and opposition divisions of the EPO will occasionally deviate from the existing practice.  
  1. Applicants would be better advised not to fall into the temptation of sprinkling the description of their European patent applications with lexical definitions of terms used in the claim, because this approach might backfire.  
  1. First, since examiners are instructed by PPN 2/25 to ask applicants to remove any inconsistencies between the claims and the description, they might insist on the inclusion of the definitions which are found only in the description into the claims; however, amendments based on the incorporation of parts of the description may open the door to subsequent objections under Article 123(2) EPC. 
  1. Secondly, it is well known that the devil is in the details: what was considered to be an appropriate definition of a term, when the description was drafted, might later turn out to be less than ideal and create all kind of problems. 
  1. Unless there is a demonstrable reason why a term has to be used in a patent application (or a patent) with a particular meaning, especially if this meaning deviates from the accepted terminology, it would in many cases – although arguably not in every case – be better to argue in favour of a certain interpretation of a term in the claims by relying on passages of the description that shed light on the technical purport of that term  in the context of the technical solution provided by an invention. Sometimes, it can be equally useful to clarify the meaning of a term by reference to passages of the description that illustrate the technical problems that an invention purports to overcome. 
  1. Offering examiners a sound technical reasoning based on an explanation of the workings of an invention, rather than relying on a purely “lexical” definition, may have the beneficial effect of engaging examiners in a proper technical analysis of the substance of the invention, while averting the risk of of bringing the discussion onto a formalistic ground about lexical definitions and the extent to which such definitions may be read or incorporated into the claims.