In this examination appeal, the concepts of 'closest prior art' vs. 'a suitable starting point' in inventive step are discussed. Decisions such as T 967/97 and T 21/08 (also cited in the present case) have tended towards the inventive step having to be assessed relative to all suitable starting points, rather than presuming the existence of one closest prior art document to be used as sole starting point.
In this case, according to the Board's preliminary opinion, the claimed invention lacked an inventive step over D1. With its letter of response, the appellant introduced a document that had been considered in a related case, D6, and argued that given the existence of D6, D1 cannot be closest prior art and that, hence, the inventive step assessment had to start from D6.
The present Board does not follow this line of argument, and rather deliberates that it cannot be true that if a claim is considered obvious with respect to D1, it cannot be rendered non-obvious if a closer prior art, e.g., D6, was found, i.e., an inventive step argument cannot be refuted merely by the introduction of another piece of prior art. Thereby, T 967/97 and T 21/08 are followed.