It is well known that clarity is not a ground for opposition under A 100 and that objections of lack of clarity against claims will not be accepted in opposition proceedings unless the lack of clarity is generated by post-grant amendments. The Boards have admitted only very few exceptions to this principle. T 656/07 has provided a rather surprising exception. As this decision is a recent one, I cite the most relevant passages for those who are not familiar with it:
[2.1] It is the position of the Board that the lack of clarity arose - at least in part - from the amendments carried out after grant. The invention as granted was defined in independent claim 1, directed to a pouch, and in independent claim 3, directed to a wafer. Claim 1 was objectively unclear since it sought to define the pouch coupling means by making reference to the wafer. The amendment to claim 1 of the main request submitted during the opposition proceedings introduces in claim 1 further features - in relation to the pouch coupling means - which were formerly contained in dependent claim 2. This makes it necessary to reconsider the coupling means claimed in claim 1 on the light of these new incorporated features - which are now considered essential due to the amendment - and also to reconsider in this new light the fact that the coupling is to be taken in connection with a body-side mounting wafer. It follows that one cannot ignore the fundamental lack of clarity generated by the cross-references.
More specifically, while the cross-reference to the wafer was already present in claim 1 as granted, the incorporation into claim 1 of further features concerning the coupling means makes it necessary to reconsider the interaction of the pouch with the wafer and as a result an objection of lack of clarity due to this new interaction emerges. Therefore, the amendments introduced into claim 1 substantially affect the clarity of claim 1 as a whole, since its subject-matter is not clearly defined. This general lack of clarity makes it impossible to compare the subject matter of claim 1 to the state of the art and to proceed further with the substantive examination of said claim.
[2.2] This lack of clarity can be objected to in opposition proceedings because it is generated by the amendments made during this procedure, even if the contested feature as such was already present in the claims as granted but in another combination. In fact, it is not enough formally to state that a feature was present in the granted version in order to limit the power of investigation of the Board as far as clarity objections arising from an amendment is concerned. It is also necessary to ascertain the effect produced by the amendments introduced into the claim as a whole since a feature of a claim is not to be seen in isolation, but through its interaction with the other features of the claimed combination. A new combination of features is also an amendment in itself.
As pointed out in T 472/88 , in the statement contained in decisions T 227/88 and T 301/87: “fresh objections based on A 84 are not allowed if such objections did not arise out of the amendments so made”, the word “arise” should be broadly construed. Among the meanings of this word registered in the cited decision and taken from the Concise Oxford Dictionary there is “bring into notice”. This means that a lack of clarity also arises out of an amendment when this amendment brings into notice an ambiguity that has existed all along. This is also the case here with the aggravating circumstance that the lack of clarity already present in claim 1 has been extended and reinforced by the amendment.
[2.3] The respondent cited decision T 367/96 in order to support its opinion that, in the present case, clarity should not be examined by the Board. However, T 367/96 [6.2], is principally concerned with a lack of support by the description, which is a separate aspect of A 84, and not with lack of clarity. Furthermore the decision cited does not state that an objection of lack of clarity cannot be raised against a combination of granted claims, but only that the lack of support was already there and has not been introduced after grant of the patent. T 367/96 [6.2] refers to a previous decision (T 301/87), but only to reiterate the generally recognized principle that the clarity objection should arise out of the amendments made.
T 853/02 [3.1.1] of the reasons, stresses also that the unclarity did not concern the amendments. These decisions do not contain any definition of an amendment. In fact, whether an amendment is given and in what it consists is a question of fact to be determined on a case by case basis.
In the opinion of this Board it cannot be stated that there is a general rule in the jurisprudence that a combination of granted claims should not be challenged for lack of clarity.
Now in the present decision the opponents tried to follow the path opened by T 656/07:
** Translation from the German **
 The opponents pointed out that the claims of the main request had become unclear as a consequence of the contraction of granted claims 1 and 6. The lack of clarity only appeared as a consequence of the contraction of the two claims because this amendment modified the focus (Schwerpunkt) of the claimed subject-matter. Thus the situation was the same as in case T 656/07.
The Board agrees with the opponents insofar as the claims as granted are seriously deficient with respect to clarity, which make it difficult to appropriately understand the claimed subject-matter […]. The Board is of the opinion that these deficiencies with respect to clarity should have been corrected during the substantive examination preceding the grant, and that the Examining Division should have insisted on the need for a precise determination of the subject-matter for which protection is sought.
However, the Board cannot see how the contraction of the features of claims 1 and 6 as granted, and the shift of focus (Fokus) of the claimed invention resulting from it, could entail a new lack of clarity. Moreover, the opponents have not specified the alleged new lack of clarity in a concrete manner.
As a rule, contracting claims without otherwise amending their wording in opposition proceedings cannot open up the possibility to attack deficiencies with respect to clarity under A 84 that already existed in the claims as granted.
The Board is of the opinion that decision T 656/07 cited by the opponents concerns a particular case that cannot be generalised. A lack of clarity of the granted claims is not as such a ground for revocation. Rather, an unclear claim has to be interpreted and the grounds for opposition have to be assessed on the basis of this interpretation.
T 656/07 opened the door a bit wider for pleading lack of clarity in opposition (and opposition appeal) proceedings. I remember that the decision was welcomed by some colleagues who dream of a revision of the EPC that would allow lack of clarity to be used as a ground for opposition. I am definitely not one of them because I think that clarity is a very subjective thing. Nothing is clear to him who does not want to understand (and opponents very often are not desirous to understand, are they?). Be that as it may, I am happy to see that T 656/07 is reduced to a “particular case that cannot be generalised”, and thus isolated. Nobody loses face and we may perhaps forget a somewhat weird decision ...