WORLD INTELLECTUAL PROPERTY ORGANIZATION
IPC COMMITTEE OF EXPERTS
Project: CE421
Amendments to the Guide of the IPC and other basic IPC
documents
Initial Proposal
Date: January 18, 2010
PROPOSAL
GUIDELINES FOR DETERMINING SUBJECT MATTER APPROPRIATE
FOR OBLIGATORY AND NONOBLIGATORY CLASSIFICATION
(I.E., “WHAT” TO CLASSIFY WITHIN PATENT DOCUMENT DISCLOSURES)
DEFINITION OF TERMS
“Invention information” in a patent document is all novel and unobvious subject matter
in its total disclosure (e.g., description, drawings, claims) that represents an addition to the
state of the art in the context of the state of the art (e.g. solution to a stated problem);
“invention information” should usually be determined using the claims of the patent
document as guidance.
“Addition to the state of the art” is the difference between the subject matter in question
and the state of the art.
“The state of the art” is the collection of all technical “things” that have already been
placed within public knowledge.
“Thing” means any technical subject matter, tangible or not, such as:
–
methods of using a product or performing a non-manufacturing operation;
–
products (articles of manufacture);
–
processes of making a product;
–
apparatus; and
–
materials from which a product is made.
“Inventive thing” means any part of the invention information which is novel and
unobvious in itself.
PROCEDURES FOR DETERMINING OBLIGATORY CLASSIFICATION
It is obligatory to classify all subject matter that constitutes invention information in a
patent document. In practice it can be difficult to objectively determine invention
information. Therefore, the best possible approximation to this ideal case has to be found.
The following procedures should be used by classifiers to determine for each of the
various types of published patent documents which technical information must be classified.
Procedure for Patents Granted after Search and Examination

All subject matter covered by the claims must be classified. This means that
classification should be based on the subject matter of each claim as a whole and on each
inventive thing within a claim.

In addition, any part of a claimed combination should be classified if it is novel
and unobvious per se.

Any unclaimed invention information should also be classified when not fully
covered by a related published application (e.g., a published divisional application).
Procedure for Applications that Have Been Searched

All claimed subject matter that appears to be novel and unobvious in view of the
search results should be classified.

Any unclaimed subject matter that appears to be novel and unobvious in view of
the search results should be classified when not fully covered by a related published
application (i.e., a published divisional application).
Procedure for Unsearched Applications Classified by an Expert in the Art

All claimed subject matter that appears to be potentially novel and unobvious in the
opinion of the expert should be classified. This opinion is based on what the examiner or
classifier remembers as being already known or obvious based on previous similar searches or
general experience; it is not an actual review of the prior art.

Any unclaimed subject matter, believed by an experienced examiner or classifier
reviewing the disclosure to be novel and unobvious, should also be classified when not fully
covered by a related published application (i.e., a published divisional application).
Procedure for Unsearched Applications Classified by a Non-Expert in the Art
The claims should be used as guidance for the subject matter to be classified.
To minimize potentially unnecessary classifications of patent documents in the search files,
the classifications of any previously published stages of the applications may be reviewed at the
time that the applications are either granted, searched, evaluated, or abandoned to confirm or
alter their obligatory classifications. However attention should be paid to any information that is
only disclosed in a previous publication to avoid the loss of information.
In situations where a classifier determines that no invention information is present
within a published patent document, at least one classification must still be assigned to the
patent document. In this exception to standard practice, the classification should be based on
the portion(s) of the total disclosure that the classifier determines is most useful. Normally,
when the subject matter of the disclosure is well represented in the prior art, a single
classification is adequate.
IDENTIFYING “INVENTION INFORMATION” TO BE CLASSIFIED
In the following, the term “invention information” is meant to also cover its best
possible approximation based upon the stage of the patent granting procedure during which
the patent document is classified.
The “invention information” in a patent document may contain several separately
classifiable “inventive things” that could each be classified in a different classification place.
The general rule is that an “inventive thing” must be classified as a whole, and not by separate
classification of its parts. The following subsections provide additional guidance for applying
this general rule in particular situations:
(a)
Each claim in a patent document potentially defines at least one “inventive thing.”
(b) If a document discloses “inventive things” of more than one category of invention
(e.g. method of manufacturing, article/product, process of using apparatus), the “inventive
things” of all categories must be classified. An example is a novel and unobvious method for
making a product (e.g., tyre) and a novel and unobvious apparatus for making this product.
This may or may not result in classifying a patent document in more than one place, since a
particular process and apparatus for making a product potentially could be classified in the
same place or in different places.
(c) Every different “inventive thing” within a single category of invention must be
classified as a whole into a classification place covering it.
(d) When a document discloses, within a single category of invention, multiple fully
disclosed alternative variants of “inventive things” (e.g. alternative types of vehicle springs),
each variant must be classified as a whole.
For variants covered by general chemical formulae (e.g., Markush-type organic
compound formulae), all variants that are “fully disclosed” within the meaning of
paragraph - of the Guide to the IPC must be classified. This principle is also used when
documents contain inventive things that are appropriate for both “function-oriented” (e.g.,
more general use) places and “application” places.
(e) Whenever a part of an “inventive thing” is determined to also be novel and
unobvious, that part should also be classified. This situation could be indicated by the part
being separately claimed in an independent claim, or by being described in detail in
the description.
DISCRETIONARY (I.E., NONOBLIGATORY) CLASSIFICATION
(a) Any portion of the total disclosure of a patent document or of non-patent
literature (e.g., technical publication) that includes subject matter determined by a classifier
or examiner to be useful for searching may be used as the basis for assignment of
discretionary classifications.
(b) Nonobligatory classifications are made at the discretion of examiners
and classifiers, subject to internal instructions of the office concerned.
(c) In specific classification places, rules or recommendations can be stated (e.g. in
the definitions of those places) in order to assist classifiers and searchers in the use of
discretionary classification. However, such rules should normally not affect the discretionary
nature of this type of classification.
GUIDELINES FOR DETERMINING WHERE TO
CLASSIFY PATENT DOCUMENTS WITHIN THE IPC
GENERAL
The Reformed IPC utilizes three distinct general classifying rules (i.e., first place
priority, last place priority, and common) for determining the appropriate groups for
obligatory classification of inventive things within subclass schemes. Optimally, the
Classification, or at least each of its subclass schemes, should when feasible use only a single
general classifying rule. This is an ultimate goal of the Reformed IPC.
Currently, many of the existing IPC subclasses use more than one general classifying
rule within their schemes (e.g., main groups in the same scheme may use different general
classifying rules). Unfortunately, until each of these mixed-rule type schemes undergoes
reclassification or reorganization, it is not possible to convert them to a single general
classification rule.
In schemes in which several general classification rules are used, it is sometimes
difficult to determine which rule to follow when selecting a group. For example, only one
main group in a scheme may use the last place priority rule and the other main groups use the
common rule. In this example, the appropriate main group is selected using the common rule
and the indented groups are selected using the general rule used by their main group.
Normally, for main groups, the general classification rule specified at the subclass level is
used for all main groups and, when no rule is specified for any main group, the “default”
common rule is used.
The “subject of the invention” within a patent document includes each distinct inventive
thing (e.g., an embodiment, a novel and unobvious subcombination) that is claimed or
disclosed. The “subject of the invention” is determined in the same manner for all of the
general classification rules. For each inventive thing, the procedure specified by the
appropriate general classification rule is followed for determining its classification within the
scheme of the specific subclass or group covering it. All inventive things forming the subject
of the invention are classified.
COVERING DISTINCT INVENTION FEATURES IN THE SAME GROUP
If two or more distinct things within a patent document separately fit within the same
group, the classification symbol of the group is allotted only once to the document.
Moreover, when an inventive thing in a patent document is appropriate for an obligatory
classification and another thing in the same patent document is appropriate for a
non-obligatory classification into the same group, the document is assigned only the
obligatory classification.
COVERAGE OF CLASSIFICATION PLACES
It is important for classifiers and searchers to remember when using any of the three
general classification rules that the inventive things proper for each subclass or group are not
just specified by their titles alone. The “explicit” coverage of any group (i.e., the subject
matter that is unambiguously stated as being properly obligatorily classified in the group) is
limited by all the restrictions to the group’s scope actually stated in the title of its subclass, all
higher level group titles under which it is indented, its own title, and relevant definitions,
notes, and limiting references.
For an inventive thing to be obligatorily classified into any group, except as noted
below, it must satisfy all of the explicit restrictions to the group’s coverage. This is important
for classifiers and searchers to remember when determining the group for which the inventive
thing is proper. For example, within a scheme, a group having a broad title that the inventive
thing does fit within should be selected for obligatory classification rather than a coordinate
group having a more restrictive title that the inventive thing almost fits within.
However, the “actual” coverage of any group is more than what is explicitly stated and
depends on other factors (e.g., the group’s interrelationship with other groups in its scheme,
the coverage of related subclasses). In addition to the inventive things explicitly covered by
its title, a group may also cover inventive things that are:

Combinations of the explicitly stated subject matter of its title with other subject
matter normally outside of the scope of its subclass, when the combination is not
clearly specified as being covered by another subclass.

Combinations of the explicitly stated subject matter of its title with other subject
matter within the scope of its subclass, when the combination is not (a) explicitly
covered by another group or (b) clearly implied as proper for another group
because of stated precedence or priority.

Categories of invention (for example, processes, products, or apparatus), that are
not otherwise provided for by another classification place, that are related to the
subject matter of another category of invention that is explicitly stated as being
within the coverage of the group. For example, the explicitly stated scope of
group A44B 19/00 is “Slide fasteners”; nevertheless the group also covers
“Making slide fasteners by processes not fully provided for in another subclass.”
In another example, the title of subclass C09K does not explicitly cover the
inventive things added to the scope of the subclass by note (1) following it.

Details or components that are specially adapted for, or used only with, the
explicitly stated subject matter of its title when they are not otherwise provided
for by another classification place.
UNIVERSAL PROCEDURES FOR LOCATING A SUBCLASS
The methods for determining the most appropriate subclass for an inventive thing are
the same for all three of the general classification rules.
Frequently, classifiers and searchers already know of one or more potential subclasses
covering the inventive thing or related inventive things. In these situations, they merely
review the subclass titles, schemes, notes, and references within the known subclasses looking
for an appropriate group. If one is found covering the inventive thing, its subclass is deemed
appropriate for classification purposes.
When classifiers do not know of an appropriate subclass or related subclasses, one or
more potential subclasses for the inventive thing are normally locatable using terms for the
inventive thing or technical terms related to the inventive thing. This is done by:

text searching of schemes, definitions, or catchword indexes using the
identified terms,

alphabetic searching of catchword indexes using the identified terms, or

text searching patent documents using the identified terms and reviewing the
classifications of those patent documents most related to the inventive thing.
After one or more potentially appropriate subclasses are found using the identified
terms, the titles, definitions, schemes, and references of the potential subclasses are checked
to determine which of these subclasses, if any, is appropriate in scope for the inventive thing.
However, since different Offices have not always identically classified the same subject
matter in patent documents, particular care must be taken when utilizing only the
classifications of patent documents to locate appropriate subclasses. Sometimes two or more
subclasses may seem equally appropriate based merely on the classifications of the documents
located. When plural subclasses seem equally appropriate for the inventive thing, the method
stated below is used to determine the correct subclass.
If classifiers are unable to determine the correct subclass for an inventive thing using the
above methods (e.g., the terms for new technology are not covered explicitly by any subclass
or group title), classifiers must follow an exhaustive systematic approach based on the
principle of hierarchy. This involves first scanning the eight sections of the IPC and selecting
possible subsections and classes by title. It is then necessary to turn to the subclass titles
under the selected classes and note those subclasses that appear to include the inventive thing.
After one or more potentially appropriate subclasses are found, the titles, definitions,
schemes, and references of the potential subclasses are checked to determine which of these
subclasses is most appropriate in scope for the inventive thing. The subclass that most
satisfactorily covers the inventive thing should be selected or, if none can be located, the most
appropriate “Subject matter not otherwise provided for in this section” subclass.
GENERAL RULES FOR SELECTING GROUPS FOR CLASSIFICATION
After selection of the appropriate subclass, the procedure using the hierarchical
structure of the IPC should be followed for determining the relevant main group and
subgroup in the identified subclass. Before applying this procedure, it is necessary to
check which of the three general classification rules, described below (the common rule,
the first place priority rule and the last place priority rule), is used in the selected subclass
and whether any special classification rules are applied within the scheme or parts of the
scheme.
While the paragraphs below indicate the differences between the three general
classification rules, it is important to remember that the general rules share the following
essential features:
(a) many inventive things are completely covered by only one group in the subclass
scheme; in this situation, the thing is classified in that group regardless of the general
classification rule used in the subclass;
(b) if two or more inventive things are disclosed in the patent document, the general
rule used in the appropriate subclass is separately applied for classifying each;
(c) if a subcombination of the inventive thing is novel and non-obvious itself, it is
separately classified according to the general rule used in the subclass appropriate for it.
It is only in situations where the inventive thing is covered by two or more groups of
the subclass (i.e., some groups have potentially overlapping scope or groups are only
available for subcombinations of the thing and not for the thing as a whole) that the general
classification rule used in the subclass is important for determining a relevant group or
groups.
“First Place Priority” Rule
Any subclass scheme where the “first place priority” rule is utilized has a note stating
that the “first place priority” rule is used in the whole scheme or in a particular set of groups.
This note is located with the subclass title or precedes the highest group in the scheme
covered by it. This type of note states, “In this subclass/main group(s)/group(s) classification
is made according to the first place priority rule (i.e., in the first appropriate place in the
scheme).” For example, see the relevant notes in subclasses C40B and F23B.
Schemes, or distinct portions of schemes, covered by this general classification rule
utilize the arrangement of groups in their scheme to determine priority and follow the
“standard subject matter sequence” concepts (i.e., more complex to less complex,
combinations to basic subject matter to details, specialized to non-specialized). This means
that groups covering the most complex or specialized invention information are located at the
top of the scheme, or distinct portion of the scheme, and those covering progressively less
complex or non-specialized invention information are successively located lower in the
scheme or distinct portion of the scheme.
Broadly stated, when this rule is applied, an inventive thing is classified by
successively, at each indentation level, locating the first group providing at least in part for the
thing, until a subgroup is selected for classification at the deepest appropriate indentation
level. When several inventive things are included within the subject of the invention, the first
place priority rule is separately applied to each of them.
Specifically, after the appropriate subclass for the inventive thing is determined, the
group in the scheme that covers this information is selected by sequentially:
1.
determining the topmost main group in the scheme which provides for this
inventive thing (i.e., the first main group that covers at least in part the inventive thing and
does not preclude the inventive thing as a whole or any portion of the inventive thing);
2.
determining, under this main group, the topmost one-dot subgroup that provides
for this inventive thing (i.e., the first subgroup that covers at least in part the inventive thing
and does not preclude the inventive thing as a whole or any portion of the inventive thing);
and
3.
repeating the procedure of the previous step through successive indentation levels
of subgroups until the topmost appropriate subgroup in the deepest (greatest number of dots)
subgroup level is determined (i.e., until the last level of indentation is reached or until none of
the subgroups at the next indentation level provide for the inventive thing).
“Last Place Priority” Rule
Any subclass scheme where the “last place priority” rule is utilized has a note stating
that the “last place priority” rule is used for the entire scheme or a particular set of groups.
This note is located with the subclass title or precedes the highest group in the scheme
covered by it. This type of note states, “In this subclass/main group(s)/group(s), in the
absence of an indication to the contrary (e.g., a reference to another group, an exception stated
in a note of the scheme), classification is made according to the last place priority rule (i.e., in
the last appropriate place in the scheme for the inventive thing being classified).” For
example, see the relevant notes in subclasses A61K, C07, C08G and C10M.
Schemes, or distinct portions of schemes, that use the “last place priority” rule use the
arrangement of the groups in their scheme to determine priority. In classification schemes
where the last place priority rule has been introduced, a sequence of groups is not formally
standardised. However, the sequence of groups frequently follows the principle of proceeding
from less complex or more general subject matter at the top of the scheme to progressively
more complex or specialized subject matter located lower in the scheme.
Broadly stated, where this rule is used, if two or more main groups or subgroups having
the same indentation level within a group branch provide for one of the facets of the inventive
thing being classified, the last group is selected. According to this rule, an inventive thing is
classified by successively, at each indentation level, locating the last group, providing at least
in part for the inventive thing until a subgroup is selected for classification at the deepest
appropriate indentation level. When several particular inventive things form the subject of the
invention, the last place priority rule is separately applied to each of them.
Specifically, after the appropriate subclass for the inventive thing is determined, the
group in the scheme that covers this information is selected by sequentially:
1.
determining the last main group in the scheme which provides for this inventive
thing (i.e., the last main group that covers at least in part the inventive thing and does not
preclude the inventive thing as a whole or any portion of the inventive thing);
2.
determining, under this main group, the last one-dot subgroup that provides for
this inventive thing (i.e., the last subgroup that covers at least in part the inventive thing and
does not preclude the inventive thing as a whole or any portion of the inventive thing); and
3.
repeating the procedure of the previous step through successive indentation levels
of subgroups until the last appropriate subgroup in the deepest indentation level (greatest
number of dots) is determined (i.e., until the last level of indentation is reached or until none
of the subgroups at the next indentation level provide for the inventive thing).
“Common” Rule
The “common” rule is the “default” general classification rule and is applied in all areas
of the Reformed IPC where no other general classification rule or special classification rule is
specified for a subclass scheme or a portion of a scheme.
Schemes, or distinct portions of schemes, that use the “common” rule require that an
inventive thing be obligatorily classified in the group within whose scope this particular
inventive thing is most completely embraced. This rule generally requires devising
subclasses and the classification schemes, or portions of schemes, where it is applied in such a
way that one and the same type of inventive thing can be classified in only one place in the
scheme. This means, for this rule to be optimally applied, that classification places must be
mutually exclusive of each other for every possible inventive thing at all hierarchical levels.
In situations where there are plural groups in the subclass scheme within which an inventive
thing could potentially fit (e.g., different groups cover portions of the entire inventive thing, a
very specific and a more general group could both cover the inventive thing), specific
procedures for determining relative priority between the possible groups are followed,
specified below, to determine which group most completely embraces the inventive thing.
In contrast to the first and last place priority rules described above, no general priority
based on the relative position of groups in a scheme is applied in the common rule areas of the
IPC. However, the following principles of priority are applied to limit unnecessary multiple
classification and to select the group that most adequately represents the inventive thing being
classified:
(a) Groups for more complex matter take priority over groups for less
complex matter. For example, groups for combinations take priority over
groups for subcombinations and groups for “whole things” take priority over
groups for “details.”
(b) Groups for more specialized subject matter take priority over groups for less
specialized subject matter. For example, groups for unique types of matter or groups for
matter with means for solving particular problems take priority over more general groups.
However, when references or local precedence rules apply, these overrule the above
principles of priority.
These principles of priority are also used to form the standardised sequence of main
groups. The standardised sequence can therefore, in many situations, be used as a guide when
applying the above priority principles. However, it should be borne in mind that the
standardised sequence gives priority between all main groups of a subclass. This includes
groups of similar complexity and groups that have a similar degree of specialisation whose
location in the sequence does not indicate an actual difference in their relative priority based
on historical placement. Thus, in the common rule areas of the IPC, when the inventive thing
can fit within two or more groups of equal complexity or specialisation, classification should
not only be made in the first appropriate group in the sequence, but in all appropriate groups
of equal complexity or specialisation.
Specifically, after the appropriate subclass for the inventive thing is determined, the
group in the scheme that most completely embraces it is selected by sequentially:
1.
Determining, by review of all of the main groups in the scheme, if only one main
group covers the inventive thing. If this is so, go to step 3.
2.
If it is determined in step 1 that two or more main groups could potentially cover
the inventive thing being classified (e.g., the group titles state only subcombinations of the
inventive thing), then the principles of priority stated above or the standardized sequence,
should be used as guidance.
(i) If these principles indicate a priority between the groups, the group given
priority must be selected. Other groups with a lower priority may also be selected for
classification if they are considered to be useful for search purposes, for example for
performing Boolean searching. Step 3 should then be applied separately for each selected
group.
(ii) If priority between the groups cannot be determined by these principles,
then step 3 should be applied separately for each group.
3.
Determining, by repeating step 1 and, if necessary, step 2 at each subsequent
hierarchical level, the appropriate subgroup in the deepest indentation level (i.e., until the last
level of indentation is reached or none of the subgroups at the next hierarchical level provides
for the technical subject).
If no specific place for a combination is provided in an area of classification where the
common rule applies, it is classified based on its subcombinations, following the principles of
priority stated above. Subcombinations not selected for classification according to these
principles should be considered for classification as additional information.
SPECIAL AND SUPPLEMENTARY RULES FOR OBLIGATORY CLASSIFICATIONS
In situations where problems exist that prevent fully covering the inventive thing, or its
novel and unobvious components, by the sole use of a single scheme and a general
classification rule, a note may be added within a scheme specifying a “special classification
procedure” for adding supplementary obligatory classifications. Such a note stipulates the
classification rule used for assigning additional obligatory classification(s), and what novel
and unobvious “aspect” of the inventive thing, or its components, the supplementary rules are
intended to cover (e.g., a novel and unobvious compound is classified based on its formula
and is also classified within a separate scheme covering one or more of its novel applications).
In a limited number of places in the Classification, special classification rules are used
for obligatory classifications. In these places, the procedures for obligatory classification
stated in the special rules override the general classification rules. Wherever special rules are
used, they are clearly specified in notes at the places concerned, e.g., C04B 38/00, C08L,
G05D. For example, Note 2 (b) following the title of subclass C08L (Compositions of
macromolecular compounds) specifies that, “In this subclass, compositions are classified
according to the macromolecular constituent or constituents present in the highest proportion;
if all these constituents are present in equal proportions, the composition is classified
according to each of these constituents.”
SELECTING NON-OBLIGATORY, i.e., DISCRETIONARY CLASSIFICATIONS
Patent documents may be assigned non-obligatory classifications to groups whenever
examiners or classifiers believe particular subject matter disclosed in the patent documents is
useful for searching.
Nevertheless, to encourage the consistency of non-obligatory classification within a
portion of a subclass scheme, procedures or recommendations may be stated (e.g., in a note)
for guidance to classifiers or examiners on how to most efficiently assign non-obligatory
classifications in this part of the scheme.
[End of document]