Rule 43⁷¹
Form and content of claims

(1) The claims shall define the matter for which protection is sought in terms of the technical features of the invention. Wherever appropriate, claims shall contain: 

(a) a statement indicating the designation of the subject-matter of the invention and those technical features which are necessary for the definition of the claimed subject-matter but which, in combination, form part of the prior art; 

(b) a characterising portion, beginning with the expression "characterised in that" or "characterised by" and specifying the technical features for which, in combination with the features stated under sub-paragraph (a), protection is sought.

(2) Without prejudice to Article 82, a European patent application may contain more than one independent claim in the same category (product, process, apparatus or use) only if the subject-matter of the application involves one of the following:

(a) a plurality of interrelated products, 

(b) different uses of a product or apparatus, 

(c) alternative solutions to a particular problem, where it is inappropriate to cover these alternatives by a single claim. 

(3) Any claim stating the essential features of an invention may be followed by one or more claims concerning particular embodiments of that invention. 

(4) Any claim which includes all the features of any other claim (dependent claim) shall contain, if possible at the beginning, a reference to the other claim and then state the additional features. A dependent claim directly referring to another dependent claim shall also be admissible. All dependent claims referring back to a single previous claim, and all dependent claims referring back to several previous claims, shall be grouped together to the extent and in the most appropriate way possible. 

(5) The number of claims shall be reasonable with regard to the nature of the invention claimed. The claims shall be numbered consecutively in Arabic numerals. 

(6) Except where absolutely necessary, claims shall not rely on references to the description or drawings in specifying the technical features of the invention. In particular, they shall not contain such expressions as "as described in part ... of the description", or "as illustrated in figure ... of the drawings". 

(7) Where the European patent application contains drawings including reference signs, the technical features specified in the claims shall preferably be followed by such reference signs relating to these features, placed in parentheses, if the intelligibility of the claim can thereby be increased. These reference signs shall not be construed as limiting the claim.