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Introduction to Japanese FI/F-Term Classification

File Index (FI) and File Forming Terms (F-Terms) are developed and maintained by the Japanese Patent Office. The scheme provides a granular classification (FI) and indexing scheme (F-Terms) that are specific to Japanese prior art.

In some technology areas where Japanese prior art dominates or is a significant portion of relevant prior art, it may be useful to search within the JP prior art database as it may contain leading edge advancements in these technologies.

According to the Japanese Patent Office, 75% of domestic Japanese applications have no non-Japanese family applications and while these applications may be classified under IPC, they do not contain an English abstract. Therefore, searching using IPC, CPC and English keywords may not capture the entire spectrum of JP prior art.

FI are revised biannually, while F-Terms are revised annually.

Structure of the FI/F-Terms


  • subdivision of IPC: similar to CPC main trunk
  • largely based on the latest version of IPC, but some are based on old versions, e.g. IPC4
  • uses a dot hierarchy like IPC
  • covers all the fields of IPC (A section to H section)

FI Structure

As mentioned earlier, the FI stems from the IPC and divides subgroups into further detailed subdivisions.

The figure below shows how the subgroups are divided. In concept, it is like the “main-trunk” of the CPC.

FI Notation

An example of FI subdivisions for G06F9/00 is shown below

Not all FIs include the extension symbol and/or the file discrimination symbol. For example:

G06F 9/00, 325

IPC symbol + extension symbol

B60G 17/015 A

IPC symbol + file discrimination symbol

G06F 9/00, 330 A

IPC symbol + extension symbol + file discrimination symbol

FI themes

An entire technical area is grouped into an area called a “theme”, which is specified by a theme code and a theme name.

There are 2600 themes in total.




FI coverage

Define the range of a theme

B65B 5/00-5/12

Theme code

  • represents a technical field
  • comprised of 5-digits consisting of alphanumeric characters, where the first numeral of each theme code represents a general technical field:

2 = residual technology (2B, 2C, 2D,…)

3 = mechanics (3B, 3C, 3D, 3E,…)

4 = chemistry (4B, 4C, 4D, 4E, 4F,…)

5 = electricity (5B, 5C, 5D, 5E,…)


Theme name

Container packaging and wrapping operation

F-Term Structure

Each theme contains F-terms, which are search keys. About 1800 themes of the total 2600 are subdivided into F-terms.

The F-term classification system is a multidimensional system that further divides the technical field of each theme into “viewpoints” that provide further information about the theme, such as materials, purposes, operations, etc. These viewpoints are similar in concept to the CPC orthogonal symbols.

F-term format

An F-term consists of a 5-digit theme code + a 2-digit viewpoint symbol + a 2-digit number. Theme codes, however, are ordinarily displayed separately, so an F-term usually consists of a 2-digit viewpoint symbol + a 2-digit number (the first 5 digits are omitted).

The general format of F-terms is: 3B120 AD04.A



Theme code

Viewpoint Digit. Additional code

Term code

Theme code: represents a technical field

Term code: includes Viewpoint and Digit

View point:

  • comprises 2 letters selected from A to Z
  • provides further information about the theme, such as materials, purposes, operations, etc. These viewpoints are similar in concept to the CPC orthogonal symbols.


  • comprises 2 numerals selected from 00 to 99
  • subdivides the viewpoint

Additional code: subdivides each term code

  • Format: .(period) + one alphabet or number

Due to the granular, multidimensional nature of F-terms, it is possible to search for patents in a highly detailed manner, by searching within the relevant theme code and combining viewpoints for each aspect of the invention.

See Annex S for an example showing F-Term structure and how to define the invention using F-Terms.

Where to find FI

There are two tools to assist in finding File Indices from IPC and CPC symbols. These are the WIPO CPC/FI Parallel View and the J-PlatPat IPC-FI-CPC scheme parallel viewer.

WIPO FI parallel view

To find the FI that corresponds to a certain IPC, WIPO CPC/FI parallel view can be used by selecting the “show CPC/FI” option and then selecting the “FI” box.

IPC-FI-CPC scheme parallel viewer

Scheme parallel viewer​​​​​​​

Where to find F-terms

Please see the section Method for finding FI and F-Term using either IPC or CPC in 4.1 Annex S - Japanese Classification​​​​​​​

How to use Japanese FI/F-Term in a search

Both J-PlatPat (using the FI/F-Term Search database) and EPOQUE (using the PATENW database) can be used to find relevant documents using theme codes and Boolean operators. This section focuses on the EPOQUE database.

Searching in PATENW database

Useful field qualifiers:





File Index classification

A61M16/08, 300 is entered as A61M16/08&300/FI

A61M16/08, 300@B is entered as A61M18/08&300B/FI

A61M16/00@Z is entered as A61M16/00&Z/F




An example of using both FI and F-terms:

The invention is directed to a catheter having a tip with a stiff end and a balloon on the outside (FI: A61M25/00&530).

In the embodiments the balloon was made of either polyurethane (F-term: 4C167 GG05) or shape memory material (F-term: 4C167 GG32).

The search statement used was:

(/FI A61M25/00&530) AND ((/FT 4C167/GG05) or (/FT 4C167/GG32))

Searching in the FI/F-Term Search Engine

FI/F-Term Search Engine

The search function using FI/F-term in J-PlatPat can be accessed via this link or from the dropdown menu from the main page.

Select FI and/or F-term as search queries.

FI/F-Term search engine input formats

Search item

Entry examples


Separate input format of F-term: Input theme "5D044" and viewpoint "DD01" separately.

Theme box


FI/F-term query box


Full input format of F-term: Input theme "5D044" and viewpoint "DD01" to the FI/F-term query box, together.

Theme box

no entry

FI/F-term query box



FI input format:

Input FI "H01L12/33"


Input FI "G11B19/00" with IPC-subdivision symbol "100" and file discrimination symbol "F"


Boolean operators





[ ]

Priority setting


Up to triple square brackets can be used.




Performs the AND operation with search keys on both sides of the operator.




Performs the OR operation with search keys on both sides of the operator.




Performs the NOT operation with the search key to the right of the operator.

Entry examples: View point RA01 and RA02 in 5D138:


Simplified entry

If inputting the query using the same part of FI or viewpoint in succession, this can be simplified by using round brackets "( )".

Simplified FI entry example - bundling on the main group level

A01C1/01*A01C1/02 ->  A01C1/(01*02)

Simplified FI entry example - bundling on the subgroup level

A01C1/01,114*A01C1/01,116@A ->  A01C1/01,(114*116@A)

Simplified FI entry example - bundling on the domestic classification symbol level

A01C1/01,114@A*A01C1/01,114@B ->  A01C1/01,114@(A*B)

The HELP List

A kind list, explanation and example for the Patent & Utility Model Search in J-PlatPat can be accessed here.


  • In an FI & F-term search, specifying an IPC symbol, FI or F-term usually searches for data on lower levels of hierarchy. In order NOT to search data on lower levels of hierarchy, add "$" in front of each search criterion. Without the “$” sign, the search will include the lower hierarchy FI/F-terms.


Search criterionRange of search
G11B5/61 is on a lower level of hierarchy than G11B15/60.





RA02 and RA03 are on lower levels of hierarchical than RA01.





  • When searching IPC subdivision symbol (e.g. G11B20/18,540) and without file discrimination symbol, “@\” is added, i.e. search query should be G11B20/18,540@\

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