F-terms are more effective tool for narrowing down relevant patent in searching.

As Excerpt from JPO- F-terms re-classify or further segment each specific technical field of IPC from a variety of viewpoints (i.e., objective, application, structure, material, manufacturing process, processing and operation method, control method, etc.). Combining F-terms with IPC effectively narrows down relevant documents in prior art search

This technology classification is much targeted and technology specific. Hence involving this tactic can be very useful in prior art searches.
Below are the some ways through which F-Terms can be identified-

• The concordance between IPC classes and F-Term classes can be found on IPDL website at the following URL: http://www5.ipdl.inpit.go.jp/pmgs1/pmgs1/pmgs
• We can also view F-term lists or descriptions by searching within the “F-term” field in the Patent Map Guidance section on IPDL.
• One can manually browse through the F-Terms, for this you have to click the F-Term link and then you can select the desired F-term theme code link in order to view the F-term list for that theme code

Although the use of F-Terms in patent searching is usually limited to investigations of Japanese national patents and their families. However, that doesn’t mean that the F-Terms cannot be used to identify non-JP references: Japanese documents are likely to have US, EP or WO family members which may be discovered indirectly by searching Japanese documents and then performing investigations into their family members.