Can Multi-claims and Multi-multi-claims be Accepted at the JPO?

What is a Multi-Multi-Claim?

Multi-claim: A claim that cites two or more preceding claims.
Multi-multi-claim: A multi-claim that cites at least one other multi-claim.

Rejection and Penalties for Violating Claims

If a claim set includes a multi-multi-claim, JPO Examiners will indicate a reason for rejection under Japanese Patent Law, Article 36, Paragraph 6, Number 4.  The applicant must overcome it by deleting the multi-multi dependency.
JPO Examiners do not examine claims violating the multi-multi-claim restriction, for other patent requirements.  This also applies to any claim that depends on a multi-multi-claim, even if that dependent claim itself is a single-dependency claim.
In other words, such claims will not receive examination for novelty, inventive step, or other substantive requirements until the formal defect is corrected.

Practical Implications for Foreign Applicants

Foreign applicants should be aware of the following practical points:

• Applications originating from the EPO: Because the EPO permits multi-multi-claims, Japanese applications based on European priority applications or EP-derived PCT applications may require amendment to eliminate multi-multi-claim structures.
• Applications originating from the United States or South Korea: These applications are less likely to require amendment, as multi-multi-claims are already prohibited in those jurisdictions.
• Applications originating from China: While China restricts multi-multi-claims, it permits certain exceptions. Because Japan does not recognize any exceptions, some Chinese-origin applications may still require amendment.
• Timing of amendment: Applicants are advised to amend claim dependencies at the time of filing in Japan, entering the national phase, or filing a request for substantive examination, in order to avoid receiving an office action based solely on the multi-multi-claim restriction.

Please note that Japan imposes no restrictions on the total number of claims or the number of independent claims, and there is no excess claim fee.
Therefore, applicants may increase the number of claims to preserve the same scope of protection that would otherwise have been achieved through multi-multi-claim structures.