Interpretation of Claims for Patentability: The Enlarged Board's Decision in G1/24

The European Patent Office (EPO) grants patents for inventions that are new, involve an inventive step, and are susceptible of industrial application. To perform this task, the EPO must first ascertain the subject-matter of the invention as defined in a patent application. This subject-matter is then compared against the state of the art to assess novelty and inventive step.

Under the European Patent Convention (EPC), the claims define the matter for which protection is sought in terms of the technical features of the invention (Article 84 and Rule 43(1) EPC). Consequently, the claims are central to the assessment of patentability throughout the entire lifecycle of a patent at the EPO, from examination to opposition. However, what role should the description and drawings play in the interpretation of the claims? And what is the legal basis in the EPC for using the description and drawings to interpret the claims?

In the opposition against European patent EP 3076804, these questions became central when the question of novelty turned on a single disputed term, which the Opposition Division (OD) interpreted according to its narrower, established meaning, rather than using a broader definition provided in the patent’s own description. The patent concerns a heated tobacco insert for a heat-not-burn device, containing a rod made from a ‘gathered sheet’ of tobacco. The Opponent argued for a broad interpretation based on an explicit definition within the patent’s own description, which stated that a ‘gathered sheet’ is one that is ‘convoluted, folded, or otherwise compressed or constricted substantially transversely to the cylindrical axis of the rod’. Under this interpretation, the claim would encompass also a ‘rolled sheet’ which was already disclosed in the prior art, thereby lacking novelty. The OD, however, took a different view. It held that ‘gathered sheet’ had a narrower, established meaning in the tobacco industry, defining it as a sheet that is ‘folded and convoluted to occupy a tri-dimensional space’. Notably, the OD supported this view by drawing an analogy from a Wikipedia entry on the term ‘gather’ in the field of sewing, illustrated as follows:

Because this ‘established meaning’ would not cover the prior art’s rolled sheet, the OD concluded that the claim was novel. 

The Opponent appealed said decision. 

Citing both diverging lines of case law and the fundamental importance of the legal point, the Technical Board of Appeal in its interlocutory decision T 439/22 referred the matter to the Enlarged Board of Appeal (EBA). The Board asked for clarification on three key questions, the substance of which can be summarised as follows:

1. What is the correct legal basis in the EPC for claim interpretation when assessing patentability? Specifically, should Article 69 EPC, which governs the extent of protection for infringement purposes, be applied?
2. May the description and drawings be consulted to interpret the claims always, or only when the claims are found to be unclear or ambiguous when read in isolation?
3. May an explicit definition of a claim term provided in the description be disregarded, and under what conditions?

On 18 June 2025, the EBA issued its decision, providing clear answers to the first two questions but finding the third question inadmissible, stating that it was encompassed by the answer to Question 2 and not necessary for the referring Board to reach a decision. From a practitioner’s perspective, the decision to leave the third question unanswered suggests that the EBA deliberately avoided setting a rigid, inflexible rule on when a definition can be disregarded. Instead, this provides the EPO examining and opposition divisions and the Boards of Appeal with the necessary flexibility to assess, on a case-by-case basis, whether applying or disregarding a patent’s self-provided definition is justifiable in the context of the entire disclosure.

Regarding the first question, the EBA acknowledged the previously diverging case law on the legal basis for claim interpretation. However, it pragmatically concluded that no single provision of the EPC provides an entirely satisfactory basis for this purpose. The EBA reasoned that Article 69 EPC and its Protocol are primarily concerned with infringement actions before national courts and the UPC. Conversely, it found Article 84 EPC unsuitable because it is formal in nature, addressing the content of the claims rather than providing guidance on how to interpret them. In this, the EBA echoed the reasoning of T 1473/19, which noted that Article 84 EPC defines a standard for clarity but is silent on the claim interpretation.

The EBA therefore concluded that there is 'no clear legal basis, in terms of an article of the EPC, for claim interpretation when assessing patentability.'

Despite this finding, the EBA confirmed there was no need to 'invent from scratch new principles of claim interpretation'. The EBA observed that in practice, the choice between Article 69 EPC or Article 84 EPC as a legal basis did not appear to affect the interpretative principles the Boards of Appeal actually applied. The applicable principles could therefore be extracted directly from this existing body of case law. The EBA distilled this case law into two fundamental principles:

1. The claims are the starting point and the basis for assessing the patentability of an invention under Articles 52 to 57 EPC.
2. The description and any drawings are always referred to when interpreting the claims, and not just in the case of unclarity or ambiguity.

The EBA confirmed that the first principle—that claims are the starting point for assessing patentability—is settled in case law. Its analysis therefore focused on the second principle, which was the source of the diverging case law.

In siding with the ‘always consult’ approach, the EBA explicitly rejected the line of case law that permitted consulting the description only when a claim was unclear or ambiguous. The Board provided two primary reasons for this rejection.

Firstly, it cited the need for legal harmonization. It found the ‘consult only when claim unclear or ambiguous’ approach contrary to the principles of Article 69 EPC and inconsistent with the established practice of national courts and the UPC. The EBA warned against the EPO deliberately adopting a contrary practice to the tribunals downstream of its patents. This stance aligns with the harmonisation philosophy behind the EPC, a principle the EBA has subscribed to for decades (e.g., G 5/83).

Secondly, the EBA presented a logical argument: the act of determining that a claim is ‘clear and unambiguous’ is itself an act of interpretation. Therefore, finding of clarity cannot be a preliminary stage to such an interpretative act.

Regarding the answer to Question 2, while the EBA decision mandates that the description and drawings must always be consulted, it refrains from offering explicit guidance on the precise methodology of this interpretation, leaving that task to the competent EPO divisions and Boards of Appeal. In Reason 11 of the decision, the EBA points to several past Board of Appeal cases - notably T 2684/17, T1871/09, and T1473/19 - which suggests that the principles applied in these decisions may be considered particularly suitable guidance for the future.

A closer look at these decisions reveals a consistent, nuanced methodology. They establish that claim interpretation is a contextual exercise, requiring the patent to be read as a coherent whole where no single part is interpreted in isolation. However, this contextual reading is not without limits. It is guided by the EBA’s first principle: that the claims are the starting point and the basis for assessing the patentability. This implies that while the description helps to understand the technical features in the claims, it should not be used to redefine them in a way that would be inconsistent with the claim language itself. The goal of this balanced approach is to reach a technically sensible understanding based on the entire patent document, while respecting the central role of the claims. In our view this is likely the path the EPO will now follow. The first true test, however, will be seeing how the Technical Board applies the EBA’s guidance in the underlying ‘gathered sheet’ case, which will provide the next crucial insights.

Finally, in a pointed concluding remark, the EBA reminded the examining divisions of the importance of a 'high quality examination of whether a claim fulfils the clarity requirements of Article 84 EPC'. It explicitly endorsed the view that the 'correct response to any unclarity in a claim is amendment'. By aligning with the EPO President’s comments on this matter, the EBA appears to support a strict approach to clarity to ensure legal certainty for the public. For practitioners, this raises a crucial question: will this final remark be used to justify the EPO’s already strict stance on clarity and its controversial requirement to adapt the description to the allowed claims prior to grant?

Should you have any questions arising from this decision, please do not hesitate to contact us at info@dcp-ip.com.