Frequently Asked Questions about the International Patent Classification (IPC)

This page provides answers to frequently asked questions about the International Patent Classification in general and about the changes implied by the reform of the IPC which entered into force on January 1, 2006.

Should you require further information about the IPC, please contact us at ipc.mail@wipo.int. 

 

General Questions Related to the IPC

  1. What is the IPC?
  2. Where can I find other IPC related information?
  3. Is the IPC home on the web searchable?
  4. What is the Strasbourg Agreement?
  5. What are the bodies of the IPC Union?
  6. Which countries are members of the Strasbourg Agreement?
  7. How many patent offices use the IPC?
  8. Which language versions of the IPC are available?
  9. Why is it useful?
  10. Where can I find complete detailed explanations of principles and rules of the IPC?
  11. What is the IPC hierarchical structure?
  12. What are the notes in the IPC?
  13. What are references in the IPC?
  14. What is the Official Catchword Index?
  15. What are the IPC editions?
  16. What is the edition indicator?
  17. Why is the edition indicator useful for searching?
  18. Which versions of the IPC are available on the Internet?
  19. How do I find a correct IPC symbol for a subject I want to search?
  20. What other patent classification systems exist?
  21. What is the relation between the IPC and ECLA?
  22. What is the relation between the Japanese FI and the IPC?
  23. What is the valid symbols file?

Questions Related to the Reformed IPC 

  1. Why was there an IPC reform?
  2. What  are the features and changes of the reformed IPC?
  3. What will change with respect to searching patent documents?
  4. What will change for industrial property offices and providers of patent related databases?
  5. What is the core level and how was it defined?
  6. What is the advanced level?
  7. What is the relation between the core level and the advanced level?
  8. What is the electronic layer?
  9. What are the definitions of subclasses and main groups in the IPC?
  10. What is the MCD?
  11. What is the standardized sequence?
  12. What is CONOPS?
  13. What is CLAIMS?
 

Technical Questions Related to the IPC

  1. How and where can I get the IPC?
  2. In which formats can I download the IPC?
  3. Where can the PDF version of the IPC be found?
  4. What IPC related files does WIPO provide?
  5. What is the Validity File?
  6. What is the Revision Concordance List?
  7. What is IPC:CLASS?
  8. Why do I need IPC:CLASS if the IPC is available on the web?
  9. Should I need to pay to WIPO if I want to use a database version of the IPC in my web service?
  10. Can I establish a link to WIPO IPC databases from my database?
  11. How can I use the IPC in my own internal system?
  12. What WIPO Standards are relevant for the IPC?
  13. What is WIPO Standard ST.8?
  14. What is the content of the different fields of Standard ST.8?
  15. What is WIPO Standard ST.10/C?
  16. What time lines are foreseen for new versions of the IPC?
 

General questions Related to the IPC

What is the IPC?

(see also paragraphs 6 to 10 of the Guide to the IPC)

The acronym IPC stands for International Patent Classification.  It is a hierarchical classification system used primarily to classify and search patent documents (patent applications, specifications of granted patents, utility models, etc.) according to the technical fields they pertain.  It therefore serves as an instrument for an orderly arrangement of the patent documents, a basis for selective dissemination of information and a basis for investigating the state of the art in given fields of technology.  Furthermore, it is used for classifying non patent literature, as for example in the JOPAL database.

The classification scheme contains about 70,000 entries, i.e. classification symbols that can be allotted to patent documents. These different classification places are arranged in a hierarchical, tree-like structure.

  • The highest hierarchical level are the eight sections of the IPC corresponding to very broad technical fields.  For example, Section C deals with "Chemistry and Metallurgy".
  • Sections are subdivided into 120 classes in the eighth edition of the IPC (IPC-8 (IPC-2006)).  Class C21, for example, deals with the "Metallurgy of iron".
  • Classes are further subdivided into more than 600 subclasses.  Subclass A21B, for example, deals with "Bakers' ovens; Machines or equipment for baking".
  • Subclasses are divided into main groups and subgroups.
  • Main group symbols always end with "/00".  For example, main group A21C 5/00 deals with "Dough-dividing machines".
  • The hierarchy of the subgroups under main groups is designated by dots preceding the titles of the entries.

IPC-2006 contains about 70,000 groups. Ten percent of the groups are main groups.

 

Where can I find other IPC related information?

You can find detailed information about the IPC on the WIPO IPC website.  Most likely you already know this site and have been linked from there to the present site.

This IPC homepage gives you access to the HTML version of the eighth edition of the IPC in English, French and Spanish.

The site also provides links to documentation describing the IPC and its use (e.g. the official Guide), its history, and the principles of its reform.  It also offers access to the documentation of the IPC revision process, i.e. meeting documents and reports of different meetings of IPC bodies.

You will find there also a link to the E-Forum which serves as a place for exchanging information and in particular documents related to the different ongoing and completed projects of the IPC revision process (such as proposals or comments).  It is freely accessible by the general public, however submission of documents and remarks is limited to participating patent offices.

 

Is the IPC home on the web searchable?

Yes, you can initiate a search on the WIPO website and you can limit the scope of the search to the IPC area.

 

What is the Strasbourg Agreement?

The Strasbourg Agreement is the legal foundation of the creation and revision of the IPC. On March 24, 1971, the Diplomatic Conference adopted the Strasbourg (IPC) Agreement Concerning the International Patent Classification, which on that date was signed by 15 States.  Following that, the International (European) Classification of Patents for Inventions became de facto the 1 st edition of the IPC.  The Strasbourg Agreement entered into force in 1975.  The members to the Strasbourg Agreement constitute the Special Union of the IPC.

 

What are the bodies of the IPC Union?

The principal bodies of the IPC Union are the Assembly and the Committee of Experts. The Committee of Experts has established two subsidiary bodies, the IPC Revision Working Group (WG) and the A dvanced Level Subcommittee (ALS).

The Revision Working Group is in charge of the revision of the core level of the IPC and meets regularly twice a year in Geneva.  Participation is open to all members of the IPC Union and the intergovernmental organizations mentioned in Article 5 of the Strasbourg Agreement.

The Advanced Level Subcommittee is in charge of the revision and further development of the advanced level of the IPC.  In order to allow for an accelerated revision of the advanced level the Special Subcommittee presently comprises only four members: the European Patent Office, Japan, the United States of America and the International Bureau of the World Intellectual Property Organization (WIPO).

The administration of the IPC revision is carried out by the International Bureau of WIPO. 

 

Which countries are members of the Strasbourg Agreement?

At present (April 2006), 56 countries are members of the Strasbourg Union.  The list of members is regularly updated.

 

How many patent offices use the IPC?

The number of countries using the IPC when publishing their patent documents is much higher than the number of the members of the Strasbourg Union; the IPC is used in more than 100 countries in the world.  The IPC is so to speak the lingua franca of the patent classification. 

 

Which language versions of the IPC are available?

 The authentic versions of the IPC are published in English and French.

There are several more national versions of the 7th edition: Chinese, Croatian, Czech, Dutch, German, Hungarian, Japanese, Korean, Polish, Romanian, Russian, Serbian, Spanish.  Many of them are available on the Internet (see the homepages of respective offices).  The Internet presentation of the IPC  provides links to various language versions.

 

Why is it useful?

(see also paragraphs 19 to 23 of the Guide to the IPC)

The IPC is used in more than 100 countries for classifying patent documents.  As such it is a very powerful tool for searching patent-related databases.  You can carry out a search (or you can modify your term based search) using IPC symbols in almost all patent-related databases.  Using the US Classification, you can carry out a high precision search in the US patent documentation and in US patent databases.  Using F-terms, you can carry out a high precision search in the Japanese documentation.  However, the IPC is used universally all over the world which enables you to search, for example, both US and JP documents.

 

Where can I find complete detailed explanations of principles and rules of the IPC?

The most comprehensive information about the structure, principles and rules of the IPC is collected in the Guide to the IPC.  The Guide is the official document approved by the bodies of the Strasbourg Agreement which explains the use of the IPC. It describes in simple terms and by means of examples the structure of the IPC and how the Classification should be used for classifying or retrieving patent documents.  The Guide is revised with each new edition of the IPC.

The  Guide to IPC-8 is published as Volume 5 of the printed publication of the core level of the IPC.  It is also available on the  WIPO IPC website.

 

What is the IPC hierarchical structure?

(see also paragraphs 19 to 23 of the Guide to the IPC)

The Classification consists of several hierarchical levels:

Sections - 1 st level

Classes - 2 nd level

Subclasses - 3 rd level

Main groups - 4 th level

Subgroups - 5 th and lower levels

Subgroups may have different hierarchical levels; their hierarchical level is indicated by a certain number of dots, with a lower level corresponding to a higher number of dots.

While the advanced level of the reformed IPC comprises all hierarchical levels, the core level comprises, with some exceptions, only the levels down to the highest subgroup levels.

 

What are the notes in the IPC?

(see also paragraph 29 of the Guide to the IPC)

In addition to hierarchical entries (sections, classes, subclasses, main groups and subgroups), the Classification contains also notes which are an integral part of the IPC.  Notes are important for proper understanding of the text of the IPC because they define specific terms, explain the scope of places and indicate how subject matter is classified.

 

What are the references in the IPC?

(see also paragraph 38-40, 48 of the Guide to the IPC)

References traditionally occur at the end of titles of IPC hierarchical entries (sections, classes, subclasses, main groups and subgroups) and in notes and point to other places in the IPC which are of relevance in the context of the technical subject matter covered by the place where they appear.

The IPC contains different categories of references:

References relevant to classification: They limit the scope of a place and are therefore also called "limiting references". There are three types of such references:  precedence references, references to application places, other limiting references.

Informative references: They indicate other places in the IPC which cover similar subject matter which could be of interest for search purposes.  For example, when searching for spectroscopic apparatus in G01J 3/00, it could be of interest to know that semiconductor detectors are classified in Section H.  As such informative references do not define the scope of a place they will be successively removed from the scheme and be available in the definitions only.

 

What is the Official Catchword Index?

The Official Catchword Index helps the users to find a starting point in the classification scheme by browsing a list of catchwords. It offers about 20,000 entries consisting of short technical terms/keywords which refer the user to an appropriate classification place.  Try to use generic topics when you are looking for a particular topic. If you did not find "Bacterial leaching", try "Hydrometallurgy", and if you did not find it, try "Metallurgy".

For the reformed IPC, there is only one version of the Official Catchword Index for both the core and advanced levels.  However, symbols belonging to the advanced level only are distinguishable from symbols existing in both levels.  It will be updated with each new version of the core level.

The Official Catchword Index is available in English and French in printed form, and online via the Internet presentation of the IPC (see the corresponding tab in the top line).

The German Patent and Trade Mark Office has prepared a more detailed version of a Catchword Index in the German language.  It offers more than 100,000 different entries. At present it is available in printed form and on the IPC:CLASS CD-ROM of IPC-7.  It will soon be made available online on the IPC website of the German Patent and Trade Mark Office.

 

What are the IPC editions?

(see also paragraphs 5, 42 and 43 of the Guide to the IPC)

The IPC is periodically revised for improving the system and for reflecting technical developments in its contents.  Since its appearance, revision of the IPC has been made, in general, in five-year intervals and every five years a new edition was published.  The current 8th edition was preceded by the 7 th edition which was valid from January 1, 2000, until December 31, 2005; the 6 th edition was in force from January 1, 1995, to December 31, 1999, and so on.

With the entry into force of the reformed, IPC this revision policy has changed. In future, the core level of the IPC will be revised every three years. However, longer time intervals are possible as well. For the advanced level, revised versions will be published in much shorter time intervals. It is possible  to have a new version every three months. However, it is not planned to have a new version before July 1, 2006.

For more information on revision policies, see the Revision Policy and Revision Procedure forthe Reformed IPC .

 

What is the edition indicator?

(see also paragraphs 42 and 43 of the Guide to the IPC)

(to be updated)

 

Why is the edition indicator useful for searching?

From edition to edition, new entries appear in the IPC because there are new technologies for which the coverage was not sufficient in the previous edition.  Frequently an existing "classification tree" was modified, because its original design did not fit the needs of the patent classifiers.  Often it was transferred to a new place where a new, different classification tree, was elaborated.

The consequence of this is that if you found an IPC entry, you should check when it entered into the IPC. If it existed since the beginning, most probably you can initiate a reliable search with that.  However, if you have an edition indicator, e.g., [5], this means that the entry entered into the IPC in the 5 th edition.  You have to check where technical subject of your interest was classified in the earlier editions.

To do this checking, use the Revision Concordance Lists.  If you used that symbol without any additional checking, you can automatically limit the scope of the search by limiting the time span covered only since the appearance of the 5 th edition (1990).

With the reformed IPC, generally, there will be no need to use previous editions of the IPC for searching because a major part of patent files will be reclassified according to the revision changes.

For easier identification, new entries in the most recent edition are presented in italics.

 

Which versions of the IPC are available on the Internet?

Online:

The internet presentation of the 8 th edition of the IPC is available via the WIPO IPC homepage.  This online version also allows printing of selected parts of the IPC.  In addition, many national intellectual property offices provide online presentations of the IPC.

The 6 th and 7 th editions of the IPC are also available on the WIPO IPC homepage.

A complete set of all IPC versions (1 to 8) is available in English, French, and German on the IPC website of the German Patent and Trade Mark Office.

PDF-files:

Currently only the core level of the 8th edition is available in PDF format.  A PDF version of the advanced level is in planning.

The complete 7 th edition of the IPC in PDF-format is available via the above-mentioned online presentation of the 7 th edition.

XML-files:

All IPC-related files of the 8th edition are available in XML format on the IPC download area. The download and use of all IPC related files provided by WIPO is free of charge.  Please note the  respective explanations on the homepage of the download area.

 

How do I find a correct IPC symbol for a subject I want to search?

(see also paragraphs 135  to 155 of the Guide to the IPC)

For the uninitiated user, it is advisable to approach the IPC by using the Catchword Index. Having identified technical terms relating to the subject to be searched, the user should consult the Catchword Index to locate a field of search.

If the use of the Catchword Index does not lead to a pertinent field of search, the user should scan the eight sections of the IPC, selecting possible classes by title.  Then it would be necessary to look at subclasses under the selected class and note a subclass which most satisfactorily covers the subject to be searched.  After selection of the appropriate subclass, the references and notes appearing in the subclass title should be checked for a more precise indication of the subclass contents.  Subclass definitions available in the electronic layer provide a more detailed description of the subject matter covered by a subclass than the rather concise title of a subclass.  These definitions should therefore be consulted if the user is not sure with respect to the scope of a subclass.

At the next step, all main groups in the subclass should be scanned for locating an appropriate main group. For a quick navigation in the subclass, a subclass index appearing at the beginning of the subclass could be used.  Again, the electronic layer also contains definitions for main groups.

Having determined the main group, the searcher should scan all one-dot groups under the main group and identify the group which seems most appropriate. In general, one-dot groups will have subordinate groups with two or more dots.  The group to be selected for search is the group which is most indented (i.e., has most dots) but which still covers the subject in question.

The above-mentioned definitions of subclasses and main groups also contain informative references to other places in the IPC which cover similar subject matter and could therefore be searched as well.

Furthermore, the homepage of the IPC provides two electronic tools for determining possible classification entries:

IPCCAT (currently open to industrial property offices only): It is a linguistic tool that allows to enter short descriptions of technical subject matter, e.g. a summary or abstract, and retrieve suggestions where such subject matter could be classified. The tool is based on a neural network that was trained with a large set of patent documents that were classified by experts.

TACSY: This tool allows to enter short descriptions of technical subject matter in natural language. 

 

What other patent classification systems exist?

There are three important classification systems used in addition by the largest patent offices (US, EP, JP). Out of these, the European (ECLA) and the Japanese systems (FI) have very close links to the IPC.

 

What is the relation between the IPC and ECLA?

ECLA is the internal classification scheme used by the European Patent Office (EPO) and it is based on the IPC, but it is much more detailed. ECLA classification codes can be used to carry out subject searches on the Esp@cenet database. This is done by either inserting an ECLA classification in the EC classification field, if known, or by clicking on the highlighted ECLA field when a bibliographic record of a patent specification known to be of interest is found.

The advantages of using ECLA are that when the classification schedules are revised, which happens quite frequently, the Esp@cenet database is revised so that only the latest codes need to be searched to cover backlog documentation. The codes are also applied consistently by one group of examiners. ECLA is available on EPO website at the URL http://l2.espacenet.com/eclasrch.

The more detailed subdivision of ECLA also serves as a source for the future revision of the advanced level of the IPC, i.e. for the more detailed subdivision of the present IPC structure.

 

What is the relation between the Japanese FI and the IPC?

FI or "File Index" is the internal classification system used by the Japan Patent Office to classify their patent documentation and to organize prior art searches more efficiently.

FI classifications are made up of an IPC subgroup, followed by an IPC subdivision symbol in the form of a three-digit number. These IPC subdivision symbols are unique to FI classes and are structured hierarchically. Optionally, a file discrimination symbol in the form of a letter can be added.

With its various subdivisions, the File Index (FI) Classification has about 190,000 entries, whereas the IPC has 70,000. FI and F-terms are available in English at http://www4.ipdl.ncipi.go.jp/Tokujitu/tjftermena.ipdl?N0000=114, or at http://www5.ipdl.ncipi.go.jp/pmgs1/pmgs1/main_page_E.

Like ECLA, the more detailed subdivision of the FI classification scheme also serves as a source for the future revision of the advanced level of the IPC, i.e. for the more detailed subdivision of the present IPC structure.

 

What is the valid symbols file?

Please refer to the question "What is the validity file" below.

 

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Questions Related to the Reformed IPC 

Why was there an IPC reform?

(see also paragraphs 42 and 43 of the Guide to the IPC)

The IPC was designed and developed for many years as a paper-based search tool.  With the advent of electronic patent databases at the end of the twentieth century, the Committee of Experts of the IPC Union decided that the IPC should be fully accommodated to the use in the electronic environment and has started the IPC reform.  It was launched in 1999 and its basic period was completed in 2005.  The new edition of the IPC, which entered into force on January 1, 2006, represents a first version of the reformed IPC.  The IPC reform was a multi-aspect process including fundamental changes to the IPC structure, its methods of revision and application.  The IPC reform was supported by the information technology projects IBIS and CLAIMS.

 

What are the features and changes of the reformed IPC?

As result of the revision projects of the last revision period, some entries of IPC-7 were amended and a number of new entries were added to IPC-7.  So far, the entry into force of IPC-8 was similar to the entry into force of earlier editions of the IPC.  You may find a compilation of these amendments in a word file here and a compilation in XML format here.

As result of several tasks of the IPC reform, further important changes have taken place.  The goals of the reform of the IPC were the creation of an universal search tool and the enhanced usability of the IPC in particular in the context of modern information technology.  The most prominent features of the reformed IPC are therefore:

  • Separation of the IPC classification scheme into two levels: a relatively stable core level of limited size and a dynamic and more extended advanced level; the advanced level includes a more detailed subdivision of the core level.
  • Different revision procedures for the two levels with different time scales: more frequent revisions of the advanced level allow for a rapid adaptation of the IPC to newly emerging technologies.
  • As a final step of any revision of the IPC, the obligatory reclassification of all patent documents belonging to the PCT Minimum Documentation which are classified in places affected by the revision; this reclassification will be completed prior to the entry into force of the revisions.
  • Establishing a Master Classification Database (MCD) for collecting all such reclassification data together with classification data of newly published documents; it will therefore contain classification data of at least all documents being part of the PCT Minimum Documentation in accordance with the most recent version of the IPC;
  • Adding an electronic layer to the IPC (the electronic layer being information published in the Internet version of the IPC, but not appearing in the paper publication).  This electronic layer will allow to present much more useful information than in the prior printed versions of the IPC which were by their very nature limited in space. Part of the electronic layer will be classification definitions for IPC subclasses and main groups (like the US Patent Classification system, which has an extensive set of definitions) and other explanatory information like chemical formula.

Further features of the reformed IPC are:

  • different representation of classification information on front pages of patent documents;
  • abolition of double-purpose schemes;
  • deletion of many indexing schemes or conversion of indexing schemes to classification schemes;
  • indexing codes will be presented in the same way and format as ordinary classification symbols; linking of indexing codes is abolished;
  • abolition of X-notations and introduction of "super residual" places in all classes;
  • introduction of new residual main groups in all subclasses where needed;
  • introduction of the "standardized sequence" of main groups as an alternative for displaying the sequence of main groups on screen;
  • informative references will progressively be removed from the scheme and be retained in the definitions only;
  • the recommendations for selecting a proper classification for subject matter to be classified have been amended;
  • some automated classification tools are provided for identifying appropriate IPC symbols based on short descriptions of technical subject matter.
 

What will change with respect to searching patent documents?

The users of the IPC do not have to be worried about changes dramatically altering the use of the reformed IPC for searching.  In effect, the reformed IPC can be used for searching patent documents as before while some new features will facilitate its application and effectiveness.  Some changes due to the reform have immediate effects from January 1, 2006, on, while other benefits will become more apparent in the long run:

  • Changes with immediate effect after January 1, 2006:
  • No changes in the format of symbols except for indexing symbols which then have the same format as ordinary classification symbols.
  • Some additional or amended entries as results of revision projects.
  • Some existing indexing schemes have been abolished or converted to ordinary classification schemes.
  • All documents belonging to PCT Minimum Documentation and published before January 1, 2006, will have been reclassified according to the new IPC-8.
  • All this up-to-date classification information will be available via the MCD from the EPO.
  • Use of new classification tools for identifying appropriate IPC symbols (IPCCAT (currently open to industrial property offices only), TACSY), available at the WIPO website.
  • Changes with effect in the long run:
  • the advanced level will in future have much finer subdivisions in many technical areas; this will allow for more precise searches.
  • the introduction of additional residual main groups in subclasses where existing main groups did not exhaust the scope of the respective subclass, and the creation of "super residual" places in all sections will avoid any improper classification of documents for which no appropriate places existed before.
  • the further development of the electronic layer will facilitate the selection of appropriate symbols for technical subject matters to be searched.
 

What will change for industrial property offices and providers of patent related databases?

Besides the above-mentioned changes with respect to the use of the IPC for searching purposes, the reform of the IPC may have impacts in the following fields:

  • Presentation of classification information on front pages of patent documents due to the amended WIPO Standard ST.10/C.
  • Exchange of data:
  • changes due to the amended WIPO Standard ST.8 and new standard ST.36;
  • IPC-related data provided by WIPO: new files, new file formats;
  • Classification/Reclassification data sent to and received from the MCD (which will be hosted by the EPO).
  • Making available of the supplementary information of the new electronic layer in addition to the classification scheme itself.
  • Offices will have the choice to use the advanced or the core level for classification.
  • Participation in reclassification for patent documents:
  • With the creation of the MCD, all patent documents belonging to the PCT Minimum Documentation and published before January 1, 2006, will be reclassified according to the advanced level of the eighth edition of the IPC.
  • Also, with each new revision of the IPC all documents belonging to the PCT Minimum Documentation which carry classifications affected by the revision will obligatorily be reclassified according to the advanced level.
  • These obligatory reclassifications will be carried out by the members of the Special Subcommittee.  The classification will be propagated to all members of a patent family having at least one member in the PCT Minimum Documentation.
  • Offices can retrieve these data including data pertaining to their national documents from MCD.  Offices not being members of the Special Subcommittee may also reclassify their own national collections and provide the respective reclassification data to the MCD.
  • Offices publishing patent documents which are not part of the PCT Minimum Documentation are encouraged to reclassify these national documents and provide the data to the MCD;  this will further improve the MCD as an efficient tool for searching patents according to most recent version of the IPC.
  • Changes in the revision policy of the IPC and the participation of members of the IPC Union:  the revision of the advanced level of the IPC will be carried out by a new body under the authority of the Committee of Experts, the so-called Special Subcommittee for the Revision of the Advanced Level. The Special Subcommittee will have a limited number of members in order to assure a rapid further elaboration of the advanced level.

WIPO Circulars IPC 107, IPC 123, and IPC 145 requested intellectual property offices to provide information regarding their plans for the implementation of changes implied by the reformed IPC.  Summaries of the results are to be found in documents IPC/CE/33/7 and IPC/CE/35/8.

 

What is the core level and how was it defined?

(see also paragraphs 29 to 31 of the Guide to IPC-8)

The core level consists of a limited number of classification places.  It comprises only hierarchically high entries and is therefore the relatively stable part of the IPC.

The IPC down to the main group level is the foundation of the core level. Additional subgroups were added to this foundation.  The selection criteria was the following: if no more than 5,000 documents belonging to the PCT Minimum Documentation are classified under an entry, most probably no more than 200 documents of a small or medium-sized patent office will be classified under that entry.  The assumption is that if there are no more than 200 documents classified under a classification entry, the manual or the computer-search based upon the classification symbol(s) is at least feasible.  The core level will be revised in three-year revision cycles.

This "light and stable version" of the IPC is therefore best suited for small and medium patent offices. According to the current expectations, many offices will publish their documents using the core level IPC symbols.

 

What is the advanced level?

(see also paragraphs 29, 32 and 33 of the Guide to IPC-8)

The advanced level is an extension of the core level.  It embraces the whole classification scheme of the IPC and is compatible with the core level, i.e. the core level can in general be considered as being a subset of the advanced level

The advanced level serves the needs of large patent offices and at least all documents belonging to the PCT Minimum Documentation will be classified according to the advanced level. The advanced level will be more frequently revised than the core level in order to provide for a rapid inclusion of new technical developments in the IPC.

The advanced level will only be available in the electronic version of the IPC. Entries of the IPC being part of the advanced level only are highlighted on the screen in yellow.

 

What is the relation between the core level and the advanced level?

The core level and the advanced level are compatible. This means that the core level is in general a subset of the advanced level, i.e. all core level entries are also part of the advanced level with identical titles and scope.

However, some exceptions are possible with respect to amendments and to references.

Amendments

Some revision projects of the advanced level may require amendments to classification places which are part of both the advanced and the core levels (e.g. main groups). Since the revision cycles of the advanced level are much shorter than those of the core level (three months rather than three years), it is possible that such amendments are adopted during the advanced level revision and enter into force for the advanced level. They will then temporarily be part of the advanced level only and will become part of the core level with the next core edition.

Similarly, amendments to the core level adopted by the Committee of Experts will temporarily be included in the advanced level until the entry into force of a new core level edition.

References

Another difference between the core level and the advanced level concerns references to other places in the IPC. Such references appear in titles, notes and subclass indices.

References in the core level

The core level is expected to be a self-sufficient classification tool, i.e. it should be usable without consulting the advanced level.  Therefore, a problematic situation could arise when a reference occurring in a core level place points to a place which is not part of the core level.

In representations of the core level only, e.g. in the printed form of the IPC, which will include the core level only, such references will be presented differently.  They will then point to the next hierarchically higher place which is part of the core level. If this hierarchically higher place is identical with the place where the reference was found, such references will be deleted in the core level.

References in the advanced level

A problematic situation could also arise with limiting references appearing in the advanced level which affect the scope of place by referring out subject matter to another hierarchical branch of the IPC.  As this will also affect the scope of the hierarchically higher core level places, these references are repeated in the relevant core level places when the core level is presented separately, e.g. in the printed form of the IPC.

 

What is the electronic layer?

(see also paragraphs 29 to 31 of the Guide to the IPC)

The electronic layer contains supplementary information which does not belong to the classification scheme of the IPC itself.  For example, the chemical illustrating formulae can be considered as information belonging to the electronic layer.  The electronic layer also includes other informative and illustrating material, such as classification definitions, informative references and illustrating drawings.  The electronic layer is accessible via the internet presentation of the IPC (see the corresponding tabs in the top-line referring to definitions and illustrations.

 

What are the definitions of subclasses and main groups in the IPC?

The definitions are a predominant feature of the reformed IPC for improving the usability of the IPC.  While former printed versions of the IPC were naturally limited in space for providing information, the online presentation of the IPC will allow for more ample room for explanations and illustrations of the scope of classification places.  Such more detailed description is the main objective of the definitions.

They consist of eight subsections:

"Title"

"Definition statement"

"Relationship between large subject matter areas"

"References relevant to classification in this subclass"

"Informative references"

"Special rules of classification within this subclass"

"Glossary of terms"

"Synonyms and keywords"

In a first step, definitions for all subclasses will be established.  With the entry into force of the reformed IPC on January 1, 2006, definitions for approximately 50 subclasses are available.  Further definitions will be elaborated continuously afterwards.  Definitions for all main groups will follow after the completion of this initial step.  Definitions are accessible via the internet presentation of the IPC (see the corresponding tab in the top-line referring to definitions).

 

What is the MCD?

The Master Classification Database (MCD) is another prominent  feature of the reformed IPC.  It is a database which collects regularly updated classification information for at least all patent documents belonging to the PCT Minimum Documentation.  The new rules governing the revision of the advanced level of the IPC require obligatory reclassification of all PCT Minimum patent documents which carry classification symbols affected by revision projects.  All such reclassification data is to be collected in the MCD and will from there be available to the public via Esp@cenet.

The MCD will therefore be the most powerful tool for searching patent documents according to the most recent version of the IPC.

Information regarding non PCT Minimum documents will completely depend on what information is supplied by national intellectual property offices with respect to their national collections of patent documents.

The operations with respect to the maintenance of MCD are detailed in CONOPS (Concept of Operations).

 

What is the standardized sequence?

The standardized sequence is an alternative for the sequence of main groups in a subclass. While the ordinary sequence is based on the numerical order, i.e. group 2/00 comes after group 1/00 and 3/00 comes after 2/00, the standardized sequence defines an order where most specialized subject matter is located highest.

The user of the reformed IPC has the choice between the two representations only for the online presentation. The printed representation will follow the numerical order of groups.

 

What is CONOPS?

The Concept of Operations (CONOPS) describes in detail different aspects for the maintenance of the Master Classification Database (MCD)  with respect to revisions of the IPC.  The reformed IPC requires mandatory reclassification of patent documents carrying classifications which are affected by adopted amendments of the IPC.  All such new classification data is to be collected in the MCD.  CONOPS describes the details of all procedures in this context. 

 

What is CLAIMS?

CLAIMS was the continuation of the IBIS projects. It had several subprojects as follows:

  • linking the IPC to the Master Classification Database set up by the Trilateral offices (EP, JP, US);
  • providing support to the translation of the IPC into national languages;
  • testing and making available tools for automatic classification (pre-classification and/or reclassification) patent documents available in computer readable format; these tools are now publicly available (IPCCAT (currently open to industrial property offices only), TACSY);
  • Improvement of the IPC training material, its extension to the reformed IPC and elaboration of Internet-based IPC training tools;
  • replacement of the old database IPCIS by the new RIPCIS system for managing the revision and maintenance of the IPC.
 

Technical Questions Related to the IPC

How and where can I get the IPC?

The complete IPC-8 will be available only via Internet and on the IPC:CLASS CD-ROM (currently under elaboration); there is no printed publication of IPC-8.  However, the internet presentation of IPC-8 allows for print-outs of parts of the IPC, e.g. subclasses.

The core level of the reformed IPC is published in printed form in English and French.  It can be ordered directly from the WIPO Electronic Bookshop. The Official Catchword Index is also available in printed form. It contains both references to core and advanced level places.

 

In which formats can I download the IPC?

All IPC-related files are available in XML format.  For a complete list of the files available see the question " What IPC related files does WIPO provide?" below.

The core level of the IPC is also available in PDF format.

A download area of the IPC-7 (ASCII, RTF and XML files) is also available on the IPC website.

 

Where can the PDF version of the IPC be found?

Currently, only the core level of IPC-8 is available in PDF from the WIPO IPC home page.  A PDF version of the advanced level is in planning.

 

What IPC related files does WIPO provide?

For the reformed IPC, WIPO provides the following IPC related files:

  • IPC scheme
  • validity file
  • revision concordance file
  • electronic layer (definitions, illustrations, chemical formula)
  • catchword index
  • compilation files

All  files are provided in  XML format.  WIPO's IPC homepage provides further documentation and DTD's of these files.

 

What is the Validity File?

For the reformed IPC, the International Bureau provides a so-called validity file for each new core and advanced level edition.

The validity file contains complete information on the validity periods of all classification symbols ever used in the IPC, i.e. it contains information on what date a particular symbol entered into force and on what date the valid use of this symbol ended.  If no such expiration date is given in the most recent validity file, the symbol is to be considered as valid for use.

The validity file does not contain any information on the titles associated with symbols.  However, it does give some more information for each symbol: it also indicates whether the symbol is to be used as indexing code or ordinary classification symbol, and it also provides an indicator for its association with the core or advanced level.

 

What is the Revision Concordance List?

The Revision Concordance List shows in table form how technical subject matter was moved between subsequent editions.  It indicated from which deleted groups or groups with a changed scope of the previous edition subject matter was moved to groups of the new edition. It is generated based upon the "transferred to" and "covered by" notations in the IPC and it is completed with information coming from offices doing reclassification of their patent documentation.  You may view it via the internet presentation of IPC-8 (see the respective tab labelled RCL in the top-line) or download a XML version.

 

What is IPC:CLASS?

IPC:CLASS is the portable CD-ROM version of the IPC.  A new version including IPC-8 is currently under elaboration.  The previous version containing all editions from the 1 st edition to the seventh can still be ordered from WIPO's electronic bookshop.

In this previous version,  IPC editions are presented in the form of full-text hypertext databases, the entries of which are linked to each other between editions using the Revision Concordance List information.

IPC:CLASS is an inexpensive product (150 Swiss francs only) recommended for those who would like to have a complete collection of all the IPC editions and for those who would like to download the IPC in a format suitable for further processing and integration into their own systems.

 

Why do I need IPC:CLASS if the IPC is available on the web?

On the web, you have access only to the 8 th, 7 th and 6 th editions in HTML (and the 7 th edition in PDF).  Should you need the Spanish, German or Russian versions, IPC:CLASS can be your everyday used tool in the patent database searching.  From IPC:CLASS you can download the previous versions of the IPC in various formats.

 

Should I need to pay to WIPO if I want to use a database version of the IPC in my web service?

No, you can download the IPC files, but you have to acknowledge WIPO's copyright if you plan a commercial use of the IPC on your site. 

 

Can I establish a link to WIPO IPC databases from my database?

Yes, please feel free to do that. The URL parameters to be used are described here.

Please inform WIPO if you established a link to our database to enable us to keep you informed if the IPC files are moved to new directories.

 

How can I use the IPC in my own internal system?

You may download the XML files of IPC-8  into your system which comprise both the core and advanced levels or you may download the PDF version of the core level.  

The use of IPC data provided by WIPO is free of charge. Please refer to the question entitled "Should I need to pay to WIPO if I want to use a database version of the IPC in my web service? ".

 

What WIPO Standards are relevant for the IPC?

Standard ST.8: it specifies the machine-readable recording of classification data related to patent documents.

Standard ST.10/C: it specifies the presentation of bibliographic data on patent documents; classification information is part of the bibliographic data and related to the INID code 51.

Standard ST.36: It specifies details of using  XML for the exchange of information.

Further information relating to WIPO Standards can be found here.

 

What is WIPO Standard ST.8?

ST.8 is a standard dealing with recording of IPC symbols on machine-readable records. This standard has special importance in the international data exchange.

ST.8 prescribes that for each classification symbol allotted to a patent document a record in form of a fixed-length field with 50 positions should be provided.

WIPO Standard ST.8 is available here.

 

What is the content of the different fields of Standard ST.8?

Standard ST.8 uses fixed length records with 50 positions for recording all information related to a symbol which was allotted to a particular document:

Positions 1 to 19 are used for recording the different parts of the IPC symbol.

Positions 20 to 27 are used to indicate the version indicator of the symbol in an eight digit format. The version indicator specifies which version of the particular symbol was used for classifying the corresponding document. The version indicator represents the date when the version of the respective symbol entered into force.

With the entry into force of the reformed IPC on January 1, 2006, this version indicator for all symbols in force and newly entering into force at that time is set to 20060101. Thus, for symbols that were already in force before 2006, this version indicator of Standard ST.8 will not give the actual date of their entry into force.

It is to be noted that the version of the symbol is not to be confused with the edition of the IPC that was used for classification (or the validity file version): if we assume that classification of a document takes place on May 15, 2007, while the symbol allotted entered into force on January 1, 2006, then the version indicator to be provided in fields 20 to 27 will be 20060101 while the advanced level version of the IPC used for classification will presumably be 20070401.

The version indicator therefore does not indicate which version of the IPC was used for classifying. This information can be deduced from fields 31 to 38, the date of action.

It should also be noted that this version indicator can be different depending on whether the core or the advanced level of the IPC are used for classification (see position 28 below). This is the case if amended core level groups enter into force in the advanced level before they enter into force in the core level (see chapter 2.9 of CONOPS and paragraph 31 of the Guide to the IPC).

For advanced level groups, this version indicator is therefore identical with the version indicator associated with a group in the official view of the advanced level which is in force at the time when the classification is carried out, with the exception that for groups that existed already before the reformed IPC this indicator is not shown in the official view.

Position 28 is used to indicate which level of the classification was used for classifying the subject matter: A for using the advanced level and C for using the core level.

It should be noted that this indicator is not meant to indicate in which level of the IPC the symbol can be found, it rather indicates which level was used for classifying the document. Thus, one and the same "core level symbol", i.e. a symbol which can be found both in the core and advanced level, may carry either a C or an A depending on which level has been used for classifying the document.  This is because offices using the advanced level for classifying take into account hierarchically higher groups of the core level and may assign them to a patent document if only core level groups are relevant for classifying a particular document.

It should also be noted that these two indicators C and A are not to be confused with the indicators C and A as used in the validity file records. In the validity file, A refers to symbols which exist in the advanced level only and do not exist in the core level.

 

What is WIPO Standard ST.10/C?

This standard deals with the presentation of bibliographic data on patent documents. One component of the bibliographic data is the IPC symbols that were assigned to a patent document when its technical subject matter was classified.

For the presentation of the symbols, four different font styles, regular, bold, italics and bold italics, may be used:

  • Symbols in "bold italics" indicate that the advanced level was used for classifying invention information;
  • Symbols in "italics" indicate that the advanced level was used for classifying additional information;
  • Symbols in "bold regular" font indicate that the core level was used for classifying invention information;
  • Symbols in "regular" font indicate that the core level was used for classifying additional information.

It should be noted that a symbol which is both part of the core and of the advanced levels (i.e. a symbol which is usually called a core level symbol) may appear on one document in bold italics and on another document in bold regular font, depending on which level was used for classifying the document (see the explanation above for the use of classifying level in Standard ST.8).

Thus, for a symbol presented in "bold regular" font the reader is readily informed that the document was classified according to the core level only and there might very well be a more appropriate classification place in the more detailed advanced level.

Example 1: document classified by using the core level

(51) Int. Cl. (2006)

G01N 21/17


G01J 3/02


G01J 9/00
 

Example 2: document classified by using the advanced level

(51) Int. Cl.


G01N 21/39 (2007.03)

 

G01J 3/02 (2006.01)

 

G01J 9/02 (2006.01)

Example 3: document classified by using advanced level in section G and core level in section A

(51) Int. Cl. (2006)

A61B 5/145

 

G01N 21/39 (2007.03)

 

G01J 3/02 (2006.01)

 

G01J 9/02 (2006.01)
 

What time lines are foreseen for new versions of the IPC?

New versions of the advanced level may enter into force on January 1, April 1, July 1, and October 1 of every year.  However, a new version will only be published upon successful completion of advanced level revision projects.  WIPO is obliged to notify offices and the general public at least 3 months in advance.

New versions of the core level may enter into force every 3 years.  WIPO is obliged to notify offices and the general public at least 6 months in advance.

International Patent Classification (IPC)

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