Raising an objection under R. 106 EPC is a procedural act and a precondition for access to the extraordinary legal remedy under Art. 112a EPC (R 4/08, R 7/08, R 3/11, R 7/11, R 16/12). The objection must be expressed by the party in such a form that the board is able to recognise immediately and without doubt that an objection under R. 106 EPC is intended. It also must be specific, indicating clearly and unambiguously on which procedural defect the petitioner intends to rely (see R 4/08, R 7/08, R 8/08, R 1/10, R 17/10, R 7/11, R 5/12, R 6/12, R 16/12: established jurisprudence, R 3/14, R 8/16).

An objection under R. 106 EPC is additional to and distinct from other statements, such as arguing or even protesting against the conduct of the proceedings or against an individual procedural finding (R 2/08, R 7/08, R 9/09, R 1/10, R 14/11, R 21/11, R 16/12). An objection must be expressly described as such (R 8/08, R 21/11). However, even if an objection does not contain an explicit reference to R. 106 EPC, it can qualify as an objection under R. 106 EPC (R 21/09; see also R 17/14, R 12/14).

In R 18/12, the Enlarged Board stated that only an objection which, in substance, raised a procedural defect which could be the subject of a petition for review under Art. 112a(2)(a) to (d) EPC could be regarded as an objection within the meaning of R. 106 EPC. In the case in hand, the Enlarged Board held that objecting, in substance, to the board's conclusion on clarity did not qualify as such an objection, even if the petitioner explicitly referred to Art. 113 EPC.