5.2. Indication of at least 'one way'

An invention is in principle sufficiently disclosed if at least one way is clearly indicated enabling the person skilled in the art to carry out the invention (T 292/85, OJ 1989, 275).

The disclosure of one way of performing the invention is only sufficient if it allows the invention to be performed in the whole range claimed (T 409/91 (OJ 1994, 653), see also T 1173/00 (OJ JO 2004, 16 point 3.2 of the Reasons), T 2172/15, T 2046/19, T 867/21 (see Catchword), T 174/21, T 1298/21 (single experimental set-up sufficient, by contrast to in T 149/21), T 552/22).

For sufficiency of disclosure (Art. 100(b) and 83 EPC), the board has to be satisfied firstly that the patent specification certainly puts the skilled person in possession of at least one way of putting the claimed invention into practice, and secondly that the skilled person can put the invention into practice over the whole scope of the claim. If the board is not satisfied on the first point that one way exists, the second point need not be considered (T 792/00, Catchword).

Disclosing one way of performing the invention may be sufficient as long as this one way also covers the whole claimed scope when combined with the common general knowledge (T 867/21).

The question whether the disclosure of one way of performing the invention is sufficient to enable a person skilled in the art to carry out the invention in the whole claimed range is a question of fact that must be answered on the basis of the available evidence, and on the balance of probabilities in each individual case (T 409/91, OJ 1994, 653 – point 3.5 of the Reasons, more recently for example T 2038/19).

The findings of decision T 292/85 (OJ 1989, 275) in relation to possible variants for a functional definition (see in particular chapter II.C.5.4 a) ) have been summarised and applied in later case law, for example in the following key decisions: T 238/88 (OJ 1992, 709, point 4.1 of the Reasons: "At least one way of carrying out the invention should be described in detail. The disclosure need not include specific instructions as to how all possible component variants could be obtained, as long as …"); T 60/89 (OJ 1992, 268, point 2.2.7 of the Reasons: it is not necessary that each and every variant can be carried out); T 19/90 (OJ 1990, 476, Onco-Mouse, fourth part, "consistent approach", and points 3.3, 3.7 and 3.8 of the Reasons); T 354/97; T 1173/00 (OJ 2004, 16, point 3.2 of the Reasons with reference to T 409/91; T 435/91; T 292/85 and T 612/92); T 986/21 ("... need not include specific instructions as to how all possible component variants ... should be obtained").

The board in T 740/90 deemed the reference to T 292/85 to be inappropriate because the invention in T 740/90 was defined by parameters rather than in functional terms. It was thus defined clearly, and the only possible variants were in the necessary starting materials for preparing the yeasts covered by the claim. The EPC did not stipulate that various ways of performing the invention had to be described (R. 27(1)(e) EPC). All that mattered in the context of Art. 83 EPC was whether the description included one way of preparing a yeast as described in the claim that a person skilled in the art could reproduce.

The mere fact that only one way of carrying out the invention is indicated does not in itself offer grounds for considering that the application is not entitled to broader claims (T 242/92, see also T 19/90 point 3.3 of the Reasons: "Only if there are serious doubts…"). No concrete evidence was available that the skilled person would be unable to extend the particular teaching of the description to a broader field by using routine methods. In view of the contribution to the art by the present applicant it would be unjustified, in the absence of well-founded reasons, to restrict the claims to the specifically exemplified embodiment (ex parte case T 242/92, issues of Art. 84 and Art. 83 EPC considered by the board).

In T 2046/19 both the opposition division and the respondent (patent proprietor) reasoned that the criterion of sufficiency of disclosure had already been met because the example disclosed one way of performing the invention. The board did not share this view, stating that the established case law meant that the person skilled in the art must be enabled to find working embodiments over the claimed range with reasonable effort. More technical details and more examples may be necessary to support claims of a broad scope (as in the present instance, where the desired result was only defined as a desideratum or result to be achieved). Thus, it must also be considered whether the patent's disclosure allows the person skilled in the art to work over the whole ambit of the claim without undue burden.

In T 500/20 the board explained that in claimed inventions that did not involve a range of parameter values or compositions, basing an argument of insufficiency on the approach that the invention would not be sufficiently disclosed across the entire breadth of the claim was inappropriate and could be rejected. This was especially so where an invention was directed at a broadly defined concept expressed in terms of generic structural or functional features of an apparatus or of a method. There it normally sufficed to provide a single detailed example or embodiment to illustrate how this concept could be put into practice in such a way that the underlying principles could be understood by the relevant skilled person to the extent that they could reproduce the claimed invention using their common general knowledge without undue burden (decision dealt with in details in this chapter II.C.5.4 d) ).

In T 149/21, the board agreed that the contested patent detailed at least one way of performing the claimed invention and thus satisfied at least R. 42(1)(e) EPC. According to the established case law of the boards of appeal, however, the claimed invention had to be reproducible over the whole claimed scope. It was thus essential to disclose at least one way of performing the claimed invention, but this was not sufficient to satisfy the requirement of Art. 83 EPC.

In T 1298/21 a single experimental set-up was sufficient, in contrast to the case in T 149/21, where the claimed method had explicitly to be able to identify and deal with even unscheduled incidents ("unplanned rolling pause on account of a failure").

In T 1809/17 the opponent argued that claim 1 was insufficiently disclosed in that it did not specify all essential features. For the board, however, the crucial point was not whether the independent claim defined all essential features but rather whether the patent specification as a whole provided the skilled person with at least one workable example of how the claimed invention could be implemented.