The European Patent Convention is silent about the need of substantiation of a request. However, according to Article 125 EPC, in the absence of procedural provisions in this Convention, the European Patent Office shall take into account the principles of procedural law generally recognised in the Contracting States. Accordingly, the Board has to take care that the general rules of fairness are respected and that any tactical manoeuvres to the detriment of any other party, here filing of auxiliary requests, which are not sufficiently substantiated, are avoided.1)