Recent decisions of the Enlarged Board of Appeal, G 1/24 and G 1/25, together with other recent Board of Appeal decisions, contain a number of important observations regarding claim interpretation before the European Patent Office. When read together, these decisions emphasise several established principles concerning the relationship between the claims, the description and the skilled person’s understanding of the patent.
These principles are not merely academic. They influence how claims are assessed for novelty and inventive step, how patentees defend granted claims in opposition and appeal proceedings, and how applications should be drafted and prosecuted in the first place. Understanding the emerging approach to claim interpretation is therefore critical for both applicants and third parties.
The following six principles can be distilled from the case law.
1. The claims are the starting point, basis and decisive reference point
In G 1/24, the Enlarged Board confirmed that “the claims are the starting point and the basis for assessing the patentability of an invention“. Subsequent decisions have emphasised that the claims are the decisive reference point for claim interpretation.
The central question is what a skilled person would objectively understand the claim language to mean. The wording chosen by the patentee is therefore the primary source of claim meaning.
2. Broad claim language receives its broadest technically sensible meaning
A longstanding principle of EPO case law is that non-specific claim language is given its broadest technically sensible meaning.
As summarised in the Case Law of the Boards of Appeal (I.C.4.1):
“It is a well-established principle laid down by the boards’ case law that a non-specific definition in a claim should be given its broadest technically sensible meaning (see T 79/96, T 596/96). For a feature defined in a negative manner, which excludes the presence of a specific element, the broadest scope of the claim corresponds to the narrowest (i.e. most limited) technically sensible definition of the element to be excluded (T 1553/19).”
The consequence is that general claim language cannot ordinarily be confined to a narrower scope merely because a narrower interpretation would better reflect a preferred embodiment, align with the invention described in the specification, or improve the patent’s prospects of validity. Unless the claim wording itself provides a basis for a limitation, the claim is generally assessed across its full technically sensible scope.
This principle was reaffirmed in T 2027/23, where the Board reiterated:
“the board finds no authority for interpreting a claim more narrowly than the wording of the claim as understood by the person skilled in the art would allow.”
For opponents, this often provides a powerful response to attempts to read additional technical restrictions into broad claim language. For patentees, it highlights the importance of ensuring that any genuinely important limitation appears in the claims themselves.
3. Claims are construed objectively by a skilled person with a mind willing to understand
The phrase “a mind willing to understand” frequently appears in EPO case law, but it is sometimes misunderstood.
In T 10/22, the Board explained that the principle simply means that:
“the skilled person when considering a claim should rule out interpretations which are illogical or which do not make technical sense”.
This does not mean that a claim should be interpreted according to what would be most convenient for the patentee.
On the contrary, the Board explained that the deciding body should take into account:
“all technically meaningful interpretations of this claim … that would objectively occur to a skilled reader“.
The relevant perspective is therefore:
“a mind willing to objectively construe a claim“,
not:
“a mind willing to understand the applicant’s or patent proprietor’s alleged intention“.
Claim construction is an objective exercise focused on the understanding of the skilled person rather than the subjective intentions of the drafter.
4. The description and drawings must always be consulted
One of the questions addressed by G 1/24 was whether the description and drawings should always be considered when interpreting a claim. The Enlarged Board answered that question in the affirmative.
G 1/25 clarified the nature of that exercise. The Enlarged Board in that decision explained that references to interpreting claims “in the light of” or “by consulting” the description and drawings do not describe different legal tests or different stages of interpretation. Rather, they describe: “the same interpretative operation: determining the meaning of the claim wording from the perspective of the skilled person based on the claims, the description and any drawings taken together.“
This emphasises that claim construction is not a two-stage exercise in which the claims are first interpreted in isolation and then corrected by reference to the description. It is a single interpretative process conducted from the perspective of a skilled person reading the patent as a whole.
5. Consultation of the description may affect claim meaning, but cannot impose unsupported limitations
The requirement to consult the description and drawings is substantive rather than merely formal. As recognised in G 1/25, the description may affect the meaning which the skilled person attributes to the claim wording. Where the patent contains an express definition of a term or a clear contextual explanation, the skilled person will ordinarily take that into account when interpreting the claim.
At the same time, the description cannot be used to impose a limitation or expansion for which the claim wording provides no basis. As the Enlarged Board stated:
“The description and drawings may affect the meaning which the skilled person attributes to the claim wording, but they cannot be used to impose on the claim a limitation or expansion for which the claim wording provides no basis.”
The key question therefore remains whether the interpretation advanced can reasonably be derived from the language of the claim itself. The description may influence the skilled person’s understanding of that language, but it cannot supply limitations that find no basis in the claim wording.
6. If a narrower scope is required, the proper remedy is amendment
The final principle follows naturally from the preceding five.
Where the patentee wishes to rely upon technical limitations that are not reflected in the claim language, the solution is amendment rather than interpretation.
In G 1/24, the Enlarged Board stated unequivocally:
“The correct response to any unclarity in a claim is amendment.”
Similarly, T 2027/23 identified as a major takeaway from G 1/24 that “it is up to a patentee to remedy discrepancies between the description and the claims“, stating that “patentees are the masters of their fate.”
In short, where narrower protection is required, amendment rather than interpretation is the appropriate mechanism.
Practical Consequences
Taken together, G 1/24, G 1/25, and the subsequent Board of Appeal decisions have important practical implications for applicants and patentees.
First, broad claim language will be assessed across its full technically sensible scope.
Second, the decisions reinforce the importance of precise claim drafting. If a particular technical feature is essential to patentability, it should generally appear in the claims rather than being left to implication from the description.
Third, the description remains critically important. While it cannot be used to import limitations unsupported by the claim wording, it helps inform the skilled person’s understanding of claim language and may provide definitions that influence how claim terms are interpreted. It also provides the basis for future amendment should broader claims later prove vulnerable.
The practical lesson for applicants is therefore straightforward. Claim drafting proceeds on the assumption that the claims will be interpreted according to their broadest technically sensible meaning. Patentability will be assessed against that full scope. At the same time, the specification should be drafted with sufficient detail, clear terminology and appropriate fallback positions to support both claim interpretation and future amendment if required.
The claims are the primary determinant of scope, but their meaning is determined from the perspective of the skilled person reading the claims, description and drawings together. The description informs, and may in some cases define, the meaning of claim terms; it does not override the claim language or supply limitations for which the claims provide no basis. Where narrower protection is required, the appropriate remedy is amendment, not interpretative rewriting.
