EPC: The Application of Intermediate Generalisation (T0824/23)

The EPO Board of Appeal’s decision T 0824/23 addresses the application of intermediate generalisation under the European Patent Convention (EPC). The case clarifies the conditions under which a feature extracted from a specific embodiment of the original disclosure may be introduced into a claim without contravening Article 123(2) EPC. This decision is particularly relevant for practitioners concerned with claim amendments during opposition or appeal proceedings.

Background

The appeal concerned opposition against EP 3 070 213 A1 (flush toilet). The issue of interest is an objection under Article 100(c) EPC. The appellant (opponent) argued that claim 1 as granted extended beyond the content of the application as filed, because the amendment involved an unallowable intermediate generalisation of the wording of the feature in the description.

Key findings

The Board confirmed the established legal framework for intermediate generalisation. According to the decision, an amendment constitutes an intermediate generalisation if:

• it extracts a feature from a specific embodiment; and
• the remaining features of that embodiment are not included in the claim.

The Board reiterated that an intermediate generalisation is allowable if a skilled person can directly and unambiguously derive from the application as filed—whether explicitly or implicitly—that a feature can be separated from the others without introducing new technical information (the “gold standard”, G 2/10, Reasons 4.5.1).

According to established Board of Appeal case law, such an omission is justified only where the extracted feature is not inextricably linked to the omitted features. In other words, there must be no clear functional or structural relationship between them, or it must be evident that the extracted features are not closely related to those that have been omitted (Case Law of the Boards of Appeal of the EPO, 11th edn., 2025, II.E.1.9.1).

These criteria are not concerned with the mere “context” in which a feature was originally disclosed. The key question is whether the skilled person would understand the isolated feature to be inextricably linked to the omitted features. Such a link exists if the skilled person would consider the omitted features necessary to achieve the technical effect associated with the isolated feature (see T 1762/21, Catchword).

Analysis and implications

T 0824/23 confirms that intermediate generalisation can be allowable. Its allowability hinges on whether the isolated feature can be regarded as independent from the omitted features.

This is not determined by the mere context of the original disclosure but by what the skilled person would directly and unambiguously understand from the description. The isolated feature can be considered independent if:

• there is no clearly recognisable functional or structural relationship with the omitted features;
• the omitted features are not necessary for achieving the technical effect associated with the isolated feature.

Conclusion

Decision T 0824/23 serves as a useful reminder that intermediate generalisations are not per se unallowable but can be allowable where the relevant criteria are met. It provides a clear application of those principles, emphasising that the key assessment lies in the independence of the extracted feature, in particular the absence of an inextricable link and the fact that the omitted features are not necessary for achieving the associated technical effect.