Abstract on Article 123(2) EPC for the decision T0873/24 of 03.02.2026

In T 873/24, in each of the originally filed sets of claims of the application, the parent and the grandparent application, the titanium to nitrogen ratio was explicitly defined by expressing their respective amounts in weight percent, as being in excess of 3.42, thus resulting in a weight ratio. In contrast, claim 1, feature F1.3 of the patent in suit did not specify that the amounts of titanium and nitrogen had to be expressed as weight percent in order to determine the ratio. Appellant 2 argued that subject-matter had been added since the application as filed (as well as the parent and grandparent applications) only disclosed a ratio based on weight but not a generalisation of the ratio by omission of the unit, as claimed.

According to the board, the case hinged on the extent to which the information found in the description might influence the interpretation of claim 1 and on what possible interpretations of the claim needed to be originally disclosed.

The board observed that most decisions acknowledged that the principles of G 1/24 as to the role of the description in claim interpretation also applied to the assessment under Art. 76(1) and 123(2) EPC. Generally, most decisions adopted a two-step approach, first interpreting the amended claim and then assessing whether the amended claim contained added subject-matter. The board identified three approaches regarding the extent to which the description was relied upon during this first step of interpreting the amended claims. Under the first approach, the description was consulted only to define the skilled person. Under the second, there was no broadening or limitation of claims based on the patent specification. The third was a holistic approach permitting broadening and/or narrowing the interpretation in view of the patent specification. The board noted that the three approaches led to a different outcome when applied to the case in hand. Under the first and second approaches, the amendment to claim 1 would be deemed to add subject-matter. The third approach would lead to the conclusion that feature F1.3 fulfilled the requirements of Art. 123(2) EPC.

After addressing the admissibility of the referral (see abstract under Art. 112(1) EPC), the board referred the following questions to the Enlarged Board (referral pending under G 1/26 – "Coated steel strips"):

"1. May a decision be considered to be "required" for the purposes of Article 112(1) EPC, if the referring Board demonstrates that the point of law in question arises out of the context of the case pending before it and, in the circumstances of the proceedings, it is reasonable for the Board to examine it and decide on it next?

2. (a) Does the fact that the claims are the starting point and the basis for assessing the patentability of an invention generally preclude a feature which is only disclosed in the description or the drawings of a patent from being read into the meaning of a granted claim, in particular if this leads to a restrictive reading of terms used in the claim?

2. (b) If the answer to question 2.a) is no: is claim interpretation the result of both reading the claims and consulting the description and drawings as a unitary process and does the claim being the starting point and the basis for assessing the patentability rule out only those interpretations which can be derived from the patent as a whole but would clearly contradict the general technical understanding of the terms used in the claim?

3. (a) When assessing compliance with Article 123(2) EPC, must a term used in a claim be assessed against all interpretations that make technical sense to the skilled reader on the basis of the claim alone?

3. (b) If the answer to question 3.a) is no: is it sufficient that only the interpretations of the subject-matter of the claim established against the background of the patent specification as a whole are directly and unambiguously derivable from the application as filed?"