On December 23, 2021, the JPO announced proposed amendments to the Ordinance for Enforcement of the Patent Act, which would forbid multiple dependent claims depending on other multiple dependent claims as a violation of Article 36(6)(iv) of the Patent[1].
A multiple dependent claim is a dependent claim that refers to more than one claim. An example of a multiple dependent claim depending on another multiple dependent claim is as follows:
Claim 1: A device comprising A.
Claim 2: The device of claim 1, where A comprises material X.
Claim 3: The device according to any one of claims 1 and 2, where A comprises material Y. [multiple dependent claim]
Claim 4: The device according to any one of claims 1 to 3, where A comprises material Z. [multiple dependent claim depending on another multiple dependent claim (claim 3)]
In summarizing the proposed amendments, the JPO provides two explanations for the change. First, multiple dependent claims which depend on other multiple dependent claims greatly increase the burden upon examiners in a manner disproportionate to the total number of claims, because the number of combinations of claimed features in such claims can increase exponentially. Second, of the major patent offices, the USPTO, KPO, and CNIPA do not allow multiple dependent claims depending on multiple dependent claims, and banning such claims would be beneficial from the viewpoint of harmonizing international standards.
At present, it is anticipated this change will apply to applications filed on or after April 1, 2022.