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. 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.
