How can I identify a harmonized subclass in the USPC?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

Harmonized subclasses in the U.S. Patent Classification System (USPC) are easily identifiable by specific designations following the subclass title. According to the MPEP:

“Subclasses that have been harmonized have a designation of “EPO,” “JPO,” or “EPO/JPO” in parentheses following the subclass title to indicate if the subclass has been harmonized with the EPO or JPO or with both systems.”

So, when browsing the USPC, look for these designations after the subclass title to quickly identify harmonized subclasses and understand which patent office(s) they are harmonized with.