[Explained by a Patent Attorney] What Are Multi-Multi Claim Limitations? Best Practices for Reducing the Number of Claims When Filing in Japan

When transferring or filing PCT applications (international patent applications) from abroad or foreign applications filed via the Paris Convention route into Japan (domestic conversion), addressing the “multi-multi claim restriction” is an unavoidable and critical practical issue.Following legal amendments in April 2022, this practice is now generally prohibited in Japan, and simply translating and filing the claims from a foreign application as-is will result in a notice of grounds for rejection. In this article, a patent attorney provides a comprehensive explanation—from the “basics of the restriction” to “best practices for reducing the number of claims when transferring to Japan”—for IP department managers and foreign patent firms.

1. Basics of Multi-Multi Claim Limitations and Their Impact on Practice

1-1. The Difference Between Multi-Claims and Multi-Multi-Claims

In the drafting of claims, a “multi-claim” refers to a claim that selectively cites two or more other claims. For example, a claim stating “the manufacturing method described in claim 1 or 2” is still valid under current law.

On the other hand, a “multi-multi claim” is a multi-claim that references another multi-claim. For example, suppose Claim 3 is a multi-claim stating “the manufacturing method described in Claim 1 or 2.” If Claim 4 is then formulated as “the manufacturing method described in any one of Claims 1 to 3,” Claim 4 constitutes a multi-multi claim. This is because it selectively references Claim 3, which is itself a multi-claim.

1-2. Effective Date of the Restriction and Background of Its Introduction

In Japan, the multi-multi-claim restriction has been introduced for PCT applications with an international filing date on or after April 1, 2022 (Reiwa 4), as well as for patent applications filed on or after that date (Patent Law Enforcement Regulations, Article 24-3, Paragraph 5, etc.).

The main reasons for introducing this restriction are “international harmonization of systems” and “reducing the burden on third parties and examiners.”While major countries such as the United States, China, and South Korea had already established strict restrictions, Japan had none, resulting in complex claim structures being introduced through foreign applications. As the rights relationships became as tangled as a spider’s web, increasing the burden on third parties in determining infringement and on the Japan Patent Office in conducting prior art searches, the restrictions were ultimately enacted through legislative amendments.

1-3. Penalties for Violations and the Risk of Examination Delays

If a request for examination is filed while containing claims that violate this restriction, it constitutes a violation of Article 36, Paragraph 6, Item 4 of the Patent Act (requirements under delegated ministerial ordinances) and will be subject to a notice of grounds for rejection.

2. Reasons for Reducing the Number of Claims in a Japanese National Phase (Domestic Phase)

2-1. Pitfalls Due to Differences in Rules Compared to Other Countries (Especially Europe)

Particular caution is required regarding multi-multi claim restrictions when converting PCT applications based on European (EP) specifications to Japan. Since multi-multi claims are tolerated in the EPO (European Patent Office), the UK, Germany, and other jurisdictions, specifications drafted according to European patent practice often contain dozens of multi-multi claims without hesitation.

2-2. Timing of Request for Examination and Voluntary Amendments

Under the Japanese patent system, a separate “request for examination” must be filed within three years of the application date. While it is common practice to file the request for examination simultaneously with the domestic entry procedures for a PCT application (such as submitting the translation), there is a pitfall here.

If a request for examination is filed at the same time as the national phase entry, the examination will begin based on the claims in the submitted translation. Consequently, if the application contains multi-multi claims, a notice of grounds for rejection will be issued immediately. To prevent this, “voluntary amendments upon national phase entry” are extremely important. It is an ironclad rule to make voluntary amendments between the completion of the national phase entry procedure and the filing of the request for examination to resolve any violations and eliminate unnecessary claims.

2-3. The Relationship Between the Number of Claims and JPO Fees (Request for Examination Fee and Patent Maintenance Fees)

The examination request fee payable to the Japan Patent Office is calculated using the formula: “Base Fee + (Number of Claims × Additional Fee).” Since an additional fee of several thousand yen is incurred for each additional claim, in cases such as EP-based applications with 50 claims, the examination request fee alone can amount to a massive expense of several hundred thousand yen. Furthermore, the maintenance fees (patent fees) payable after the patent is granted also become expensive in proportion to the number of claims.Reducing the number of claims during the transition to Japan is an extremely effective cost-saving measure.

3. Best Practices for Reducing and Optimizing the Number of Claims

When transitioning a foreign application to Japan, we present four practical best practices for optimizing costs while maintaining strong rights, rather than simply cutting claims.

3-1. Eliminating Multi-Multi Claims and Clarifying Dependency Relationships

To resolve multi-multi claims, the following measures are primarily taken.

3-2. Boldly Deleting Claims of Substantially Low Value

The most effective way to reduce the number of claims and significantly cut examination fees is to “delete claims of low value.” From a Japanese practical perspective, the following types of claims—which are often deemed unnecessary—tend to be included:

3-3. Integration and Organization of Categories

In the original language specification of a PCT application, it is common to list independent claims with similar components across multiple categories—such as “apparatus (article),” “manufacturing method,” “system,” and “program”—to prevent omissions in the scope of protection.

Attempting to secure rights for all of these in Japan as-is would double the number of claims. Under Japanese patent law, for example, if you hold a patent for a “program,” it is often easy to include the manufacture and sale of the “apparatus” on which it is installed within the scope of enforceable rights. The best practice for maximizing cost-effectiveness is to narrow down the categories to those truly necessary in Japan and file a request for examination after consulting with the client regarding the nature of the invention and their business model.

3-4. Proactively Strengthening Patent Requirements Through Voluntary Amendments

It is also important to strengthen patent requirements by adding strong technical features described in the examples (detailed descriptions) of the specification to the claims at the time of voluntary amendment during the transition to Japan.

If a negative opinion is expressed in the PCT International Search Report (ISR) or similar documents, there is a high probability that the application will be rejected if a request for examination is filed in Japan as is. By amending (narrowing) the claims in advance to comply with Japanese examination standards through amendments made after the translation is submitted, the probability of obtaining a patent grant on the first attempt increases. This allows for the complete elimination of patent attorney fees and translation costs associated with intermediate proceedings, delivering excellent cost-effectiveness.

4. Benefits of Engaging a Patent Attorney for the National Phase Entry and Claim Amendments

By engaging a patent attorney specializing in patents, it becomes possible to have the entire specification carefully reviewed and to strategically reconstruct the claim structure by working backward from the perspective of infringement litigation—specifically, by identifying “what are the essential features at the core of the invention” and “where competitors are likely to design around the claims.” This approach embodies the professional expertise to preserve the rights that need to be protected while trimming away only the unnecessary excess.

By selecting and refining claims at the “English (original language) stage” before translation into Japanese begins, you can directly reduce not only Patent Office stamp duty but also translation costs themselves. Having a patent attorney well-versed in Japanese examination standards refine the claims in advance drastically reduces the risk of receiving unnecessary notices of grounds for rejection, ultimately minimizing the total cost from filing to grant.

5. Summary: Entrust Secure Patent Grant and Cost Optimization to Experts

The restrictions on multi-multi claims introduced by the 2022 legal amendments are an unavoidable hurdle in the practice of transitioning PCT applications to Japan. However, rather than viewing this as merely a “troublesome rule,” it should be seen as “an excellent opportunity to review the claims as a whole, reduce unnecessary costs, and extract and strengthen only the rights that are truly necessary.”To avoid the increased risks and costs associated with filing a request for examination based on a direct translation, proper claim reorganization and voluntary amendments at the stage of national phase entry are essential strategies.