4.2.2.2.2 First Place Priority Rule

Date Published

In certain areas of classification, priority classification rules are applied. The purpose of these rules is to improve consistency of classifying. As opposed to the common rule, the priority rules give general priority rules between all groups in the given area. In order to enable this, the schemes have been specially adapted for the particular rule.

Example: Note (3) of G06Q states that

“3. In this subclass, the first place priority rule is applied, i.e. at each hierarchical level, in the absence of an indication to the contrary, classification is made in the first appropriate place”.

According to the first place priority rule, a technical subject of the invention is classified by successively, at each indentation level, locating the first group covering any portion of the technical subject, until a subgroup is selected for classification at the deepest appropriate indentation level. When several particular technical subjects are disclosed in a patent document, the first place priority rule is separately applied to each of them.

This standardised sequence follows the principle of proceeding from more complex or specialised subject matter at the top of the scheme to less complex or less specialised subject matter located lower in the scheme.

After selection of the appropriate subclass for the subject of the invention, the following procedure is applied for identifying a detailed classification place:

a) determining the first main group in the subclass which provides at least in part for the subject of the invention;

b) determining, under this main group, the first one-dot subgroup which provides at least in part for this subject of the invention;

c) repeating the procedure of the previous step through successive indentation levels of subgroups until the first subgroup at the deepest subgroup level (i.e., with a maximum number of dots) which provides for the subject of the invention is determined.


Example (hypothetical):

  • Inventive subject matter: characterised by both Wind and Chemical energy
  • Relevant CPC scheme:

A (1/00) main group

  • A1(1/02) Electrical energy
  • A2(1/04) Wind energy
  • A3(1/06) Solar energy
  • A4(1/08) Chemical energy
  • When the first place priority rule is applied, the invention should be classified under A2.


If the matter to be classified relates to a combination of elements covered in an area where the first place priority rule applies and no specific place for the combination is provided, the combination is classified in the first group that provides for at least one of its sub-combinations. Any other sub-combinations which are determined to be novel and non-obvious must also be separately classified following the first place priority rule procedure. Sub-combinations which are considered to represent information of interest for search may be classified as additional information.