Indirect Patent Infringement in Japan: What Acts Constitute Infringement Beyond Direct Use?

Direct patent infringement typically involves the unauthorized making, using, selling, offering for sale, or importing of a patented invention. However, patent rights can be significantly undermined if protection is limited only to these direct acts. Often, the most effective way to control infringement is to address activities that, while not direct infringements themselves, substantially contribute to or facilitate such infringements by others. Japanese patent law, like that of many other countries, recognizes this need by providing for "indirect infringement" (kansetsu shingai).

Article 101 of the Japanese Patent Act specifically defines certain preparatory or contributory acts that are deemed to constitute patent infringement. These provisions aim to offer patentees more effective and practical means of enforcing their rights, particularly when direct infringers are numerous and difficult to pursue individually (such as end-users), or when it is more efficient to target the source of infringing components or materials.

The Purpose of Indirect Infringement Provisions

The core rationale behind indirect infringement provisions is to prevent the circumvention of patent rights by targeting acts that have a high probability of inducing or leading to direct infringement. By holding liable those who knowingly supply key components or means for infringement, the law seeks to provide robust protection to patent holders and deter activities that would otherwise hollow out the value of a patent.

Categories of Indirect Infringement under Japanese Patent Act Article 101

Article 101 of the Japanese Patent Act outlines several specific categories of acts that are considered indirect infringements. The primary categories involve the supply of certain types of articles:

1. Supplying Articles for "Exclusive Use" (Sen'yōhin) - Article 101, Items 1 and 4

This is one of the most straightforward categories of indirect infringement. It applies to the commercial production, assignment (e.g., sale), lease, display for assignment or lease, or importation of articles that are used exclusively for:

• The production of a patented product (Item 1); or
• The use of a patented process (Item 4).

The key here is "exclusively." For an article to fall under this provision, it must have no other economically, commercially, or practically significant use beyond working the patented invention. Mere abstract, theoretical, or minor experimental alternative uses generally do not negate this exclusivity. For example, if a piston is designed and sold for use only in a specific patented engine, supplying that piston would constitute indirect infringement. The logic is that if an item's sole utility is tied to a patented invention, its supply will inevitably lead to direct infringement.

2. Supplying "Indispensable Articles" with Knowledge (Fukaketsu na Mono) - Article 101, Items 2 and 5

This category extends liability to the supply of articles that are not necessarily for exclusive use but are nonetheless crucial to the patented invention, provided certain conditions are met. It covers the commercial production, assignment, lease, display for assignment or lease, or importation of articles that are:

• Indispensable for solving the problem addressed by the patented invention;
• Not commonly available products in Japan (i.e., they are not generic, staple articles of commerce like standard screws, basic chemicals, or widely used off-the-shelf components); and
• Supplied with the knowledge that the invention is patented and that the article is to be used for working the patented invention.

This applies to articles used for working a patented product (Item 2) or a patented process (Item 5). Each of these conditions warrants closer examination:

• "Indispensable": The article must directly provide the characteristic technical means of the patented invention which were not found in the prior art and are essential for achieving the invention's solution to a technical problem. It could be a unique component that forms part of the patented product or is used in the patented process, or even a specialized tool or raw material that is critically necessary to implement a key feature of the invention. For instance, a special pigment for an erasable ballpoint pen ink could be considered indispensable.
• "Not Commonly Available in Japan": This limitation aims to prevent an overbroad extension of patent rights that might ensnare suppliers of general-purpose goods. The focus is on excluding items that are staple commodities or widely used standard components, rather than just assessing sheer market availability. For example, even if a standard word processing software package (which might be readily available) is technically indispensable for certain features of a patented information processing device, its status as a commonly available product could exempt its supply from this type of indirect infringement if it has substantial non-infringing uses (though this point was nuanced in a case concerning a software's help function, where the software itself, if its infringing use was known, could still be an article for indirect infringement if other conditions were met. See, e.g., Tokyo District Court, February 1, 2005; Intellectual Property High Court, September 30, 2005).
• "Knowledge" (Akui): The supplier must know that the invention their article serves is patented and that the article they are supplying is intended to be used for working that patented invention. This knowledge requirement often means that a patentee will typically provide a warning notice to the supplier. However, knowledge can also be inferred from other circumstances.

3. Possessing Infringing Articles for Assignment or Export - Article 101, Items 3 and 6

A third category of acts deemed to be indirect infringement involves the possession of certain articles for the purpose of assignment, lease, or export. Specifically:

• Possessing a product that would constitute a direct infringement of a patent for a product invention (if it were produced, used, etc.) for the purpose of assigning, leasing, or exporting it (Item 3).
• Possessing a product produced by a patented process, for the purpose of assigning, leasing, or exporting it (Item 6) (this applies if the process patent itself also extends to the product directly obtained by that process).

These provisions target downstream activities involving already-infringing articles, aiming to stop their further commercial dissemination.

The Relationship with Direct Infringement: Is Direct Infringement a Prerequisite?

A significant legal question is whether an act of indirect infringement can occur if there is no corresponding act of direct infringement, or if any potential direct infringement is legally excused. The prevailing view in Japan, often termed the "dependent theory" (jūzokusetsu), is that indirect infringement is generally contingent upon the occurrence or high likelihood of direct infringement. If direct infringement is not possible (e.g., the acts occur entirely outside Japan's jurisdiction), or if it is excused by law (e.g., acts for experimental or research purposes, acts covered by prior use rights, or acts involving an exhausted patent right), then actions that might otherwise constitute indirect infringement will typically not be actionable.

However, there's an important and widely accepted exception to this dependency principle:

The Exception: Supplying for Private or Household Use

Even if the ultimate working of the patented invention is by end-users in a private or household capacity (which is generally not considered direct infringement because it's not "as a business" under Article 68 of the Patent Act), the commercial supply of articles—especially those for exclusive use—that enable such private working can still constitute indirect infringement by the supplier.

The rationale is that while individual, non-commercial use by end-users is exempted from direct infringement liability for policy reasons (such as the de minimis nature of the impact and enforcement difficulties), this exemption should not extend to businesses that commercially profit by facilitating widespread private use of the patented invention. Such suppliers are, in effect, commercially exploiting the invention.

A notable case illustrating this principle is often referred to as the "bread maker" case (Osaka District Court, October 24, 2000). The patent in question was for a method of making bread using a timer function in a specific sequence. The defendant sold bread-making machines. The instruction manual accompanying these machines guided consumers to use the machines in a way that, if followed, would perform the patented bread-making method. Even though the end-users were typically making bread for household consumption (a non-commercial activity), the court found that the defendant, by selling the bread makers whose primary utility for making the specific type of bread involved the patented method, was liable for indirect infringement of the method patent. The bread maker was deemed an article for the exclusive use of the patented method in that context.

Acts Not Typically Covered by Indirect Infringement

It's important to note that Article 101 provides an exhaustive list of acts deemed to be indirect infringement. General acts of inducing or abetting patent infringement, if they do not fall within one of these specific categories, are generally not considered indirect infringement for the purpose of obtaining injunctive relief under patent law. While such acts might potentially give rise to joint tortfeasor liability for damages under general civil law principles, they are outside the specific statutory framework of Article 101 for patent-specific remedies like injunctions. This is because Japanese civil law does not generally grant injunctive relief based on general tortious conduct, and Article 101 is seen as defining the precise scope of contributory acts that warrant such patent-specific remedies (Tokyo District Court, August 17, 2004).

Conclusion

The indirect infringement provisions in Article 101 of the Japanese Patent Act significantly enhance the protective power of a patent. They extend liability beyond those who directly make, use, or sell the patented invention to those who supply key articles that enable or are indispensable to such infringing activities. By targeting upstream commercial activities that are highly likely to result in direct infringement, including the commercial supply of goods for private end-use, these rules offer patentees a more potent tool to safeguard their innovations and combat infringement effectively. For businesses involved in manufacturing, distributing, or importing components or materials, a keen understanding of these indirect infringement principles is crucial to navigate the patent landscape in Japan and avoid potential liability.