a) Currently predominant approach 

Two decisions in particular have affirmed the applicable law, setting out the now predominant approach after summarising and analysing the case law to date: T 1811/13 (decision in English - lack of clarity vs. insufficiency of disclosure) and T 647/15 (decision in French). An example of a decision in German is T 548/13.

While these decisions were not the first (see e.g. T 2290/12) to take the approach currently applied by the majority of the boards, their findings are taken here to illustrate the point.

The approach is as follows: "today there is agreement or at least a clearly predominant opinion among the boards that the definition of the "forbidden area" of a claim should not be considered as a matter related to Art. 83 EPC." The board added that: "This is not to say that a lack of clarity cannot result in an insufficient disclosure of the invention. However, in such a case it is not sufficient to establish that a claim lacks clarity, but it is necessary to establish that the application or patent, as the case may be, does not disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. In other words, it is not sufficient to establish a lack of clarity of the claims for establishing lack of compliance with Art. 83 EPC 1973; it is necessary to show that the lack of clarity affects the patent as a whole (i.e. not only the claims) and that it is such that the skilled person – who can avail himself of the description and his common general knowledge – is hindered from carrying out the invention".

As already stated, these decisions are not the first ones that represent the currently applied approach. Examples of decisions prior T 1811/13 that also follow the current majority approach: T 1948/10, T 608/12, T 2331/11, T 1507/10, T 943/00, T 960/98, T 619/00, T 396/02, T 1033/02, T 452/04, T 466/05, T 1586/05, T 1015/06, T 1250/08, T 593/09, T 1507/10, T 2331/11, T 2290/12, T 647/15, T 548/13, T 466/05, T 2290/12, T 1886/06, T 1608/13, T 608/07.

The decision in T 608/07 (hidden objection) is very often cited (especially its point 2.5.2 of the Reasons) in the case law, including even in recent decisions, e.g. in T 786/15 (Tg parameter – ambiguity at the edges of the values); T 1627/17; T 1768/15; T 1960/14 (melting points of palm oil fraction); T 1608/13 (definition of a sieving coefficient); T 1285/15 (example of a hidden clarity objection); T 593/09 (also referring to T 815/07 and Kirin-Amgen Inc v. Hoechst Marion Roussel Ltd [2004] UKHL 46 of the United Kingdom's House of Lords). In T 593/09 (ill-defined parameter) the board held (see catchword and point 4.1.4 of the Reasons) that what is decisive for establishing insufficiency within the meaning of Art. 83 EPC is whether the parameter, in the specific case, is so ill defined that the skilled person is not able, on the basis of the disclosure as a whole and using common general knowledge, to identify (without undue burden) the technical measures (e.g. selection of suitable compounds) necessary to solve the problem underlying the patent at issue. The decision in T 593/09 (essential parameter for preparation of a product) is in turn frequently cited still in recent case law, e.g. T 1305/15 (Zeta potential of hollow fibre membrane – severe lack of information concerning the ZP measurement method – ill-defined parameter not reliably measurable – Art. 83 EPC not satisfied); T 1526/09 (vague definition of parameter affected clarity but did not prevent reproduction of the claimed product); T 2403/11; T 786/15.

Examples of decisions since T 1811/13 endorsing the predominant view: T 1900/17; T 2319/14; T 417/13; T 548/13.

In T 646/13 the board considered a request for a referral to the Enlarged Board filed in view of a divergence between T 1811/13 and T 464/05 but refused it on the ground that this alleged divergence instead illustrated a development in the case law.

T 626/14, which endorsed T 464/05, likewise analysed the decisions in T 1811/13 and T 464/05. The board in T 250/15 held that T 626/14 did not call the case law confirmed in T 1811/13 into question and declined to make a referral to the Enlarged Board, considering that T 626/14 and T 464/05 concerned a particular constellation in a certain technical field.

The board in T 1845/14 took issue with the approach taken in some decisions to defining the term "invention" for the purposes of Art. 83 EPC. Addressing the rationale of T 593/09, T 815/07, T 172/99 and T 608/07, it found that, although the expression "promise of the invention" in light of Zipher Ltd v. Markem Systems Ltd referred to in T 608/07 could be understood to correspond to the indication in the description of the patent of the technical benefits provided by the claimed subject-matter, this decision from the High Court (UK) makes clear that not fulfilling the "promise of the invention" is rather an issue of inventive step. The board in T 409/17 considered T 1845/14 and T 593/09.