2.3 Search in neighbouring fields 

The search division carries out the search in document collections and databases in which it can expect to find material covering all the technical fields directly relevant to the invention. The search strategy determines which parts of this documentation should be consulted. The scope of the search may then have to be extended to parts covering neighbouring fields, but it is for the search division to decide in each individual case whether this is necessary in view of what it has already found in the initially consulted parts (see B‑III, 3.2).

When deciding which technical fields are to be regarded as neighbouring in a particular case, the search division has to consider what appears to be the invention's essential technical contribution and not only the specific functions expressly mentioned in the application.

It is left to the search division's discretion whether to widen its search to include fields not mentioned in the application. In deciding on this, it does not put itself in the inventor's shoes and does not try to imagine every single possible application of the invention. The most important question guiding its decision is whether searching in neighbouring fields is likely to uncover material on which a reasonable inventive-step objection could be based (see T 176/84, T 195/84 and G‑VII, 3).