Welcome to the new version of the Patents Manual. Please note there are changes to the numbering and sequence of the chapters and pages in the manual. You are encouraged to take the time to explore and familiarise yourself with this new structure. Guidance about C-Sets Information in Scheme and Definitions

Date Published

Instructions about the C-Sets construction and syntax are presented in a standard format in all C-Sets authorised subclasses.

As a general guidance, the specific C-Sets rule is located at only one place of the base symbol in the definitions. The placement of the specific C-Sets rule follows the CPC scheme hierarchy. If the C-Sets rule is applicable to all groups of a subclass, it is located at the subclass level only. If the same C-Sets rule is applicable to multiple groups or subgroups within the same subclass, the C-Sets rule is placed at the highest group or subgroup of the multiple groups. A reference usually is placed in the lower groups, indicating the location of the C-sets rule.

With respect to the presentation of C-Sets information in the CPC, first, in the Scheme, a Note at the subclass level states the use of C-Sets in the subclass, and also refers to the Definitions for the detailed C-Sets rules. As further notification, a similar Note may be also placed at the specific group level where C-Sets are applied.

Secondly, in the Definitions, specific guidance about the intended usage and syntax of C-Sets is detailed in the section “Special rules of classification”.

At subclass level, a table indicates the pertinent types of C-Sets using symbols of the subclass as base and/or subsequent, and the place where the corresponding C-Sets rule can be found.

Example: summary of all C-Sets in subclass C12Q

Base Symbols

Subsequent Symbols

C-Sets Rules

C12Q1/68-C12Q1/6874, C12Q1/6897, C12Q1/70






  • As shown in the above table, there are two types of C-Sets in C12Q.
  • In the first type, both base symbols and subsequent symbols are from C12Q and the C-Sets construction is explained in the “Special rules” of C12Q1/68.
  • In the second type, the base symbols are from C12N, while the subsequent symbols are from C12Q and the C-Sets rules are in the “Special rules” of C12N15/10.

Finally, at the subclass, group or subgroup level, the specific C-Sets rules describe the detailed information about the C-Sets construction and the associated syntax.

C-Sets rules are presented with the following three subheadings under the heading Special rules of classification:

  • C-Sets statement
  • C-Sets syntax rules
  • C-Sets examples

The C-Sets statement indicates which technical features are classified in the base and subsequent symbols of the C-Sets.

The C-Sets syntax rules specify the number of symbols in a C-Set; whether duplicate symbols and breakdown codes are allowed or not; the relevance of the order in the string of symbols; and any other special rule relevant for the C-Sets in question.

Amended Reasons

Amended Reason Date Amended
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