Seeking Injunctive Relief for Patent Infringement in Japan: A Practical Guide for U.S. Rights Holders

Japanese Attorney at Law - Bengoshi L.L.

• 8 min read

For U.S. companies and other patent holders, the ability to stop infringing activities in key markets like Japan is often the most critical remedy sought in patent disputes. Japanese patent law provides robust mechanisms for obtaining injunctive relief, both on a permanent basis through a main infringement lawsuit and on an interim basis via preliminary injunction proceedings. Understanding the requirements, procedures, and strategic considerations for seeking such relief is essential for effectively enforcing patent rights in Japan.

Permanent Injunctive Relief in a Main Lawsuit (Patent Act Article 100)

The primary statutory basis for seeking a permanent injunction against patent infringement is Article 100 of the Japanese Patent Act.

Statutory Basis and Scope:

  • Article 100(1): This core provision empowers a patentee or an exclusive licensee to demand that a person who is infringing their patent right or exclusive license, or who is likely to infringe, cease such infringement (侵害の停止 - shingai no teishi) or prevent such infringement (侵害の予防 - shingai no yobō).
    This means action can be taken not only against ongoing infringing activities but also to proactively prevent imminent future infringements.
  • No Requirement for Infringer's Intent or Negligence: A crucial aspect of injunctive relief under Article 100 is that it is a right akin to a real property right (bukken-teki seikyūken). As such, the patentee does not need to prove that the infringer acted with intent or negligence. The mere fact of infringement (or a clear likelihood thereof) is sufficient to ground a claim for an injunction. This distinguishes injunctive relief significantly from claims for monetary damages, which are based on tort law and generally require fault (though negligence is presumed in patent infringement cases under Article 103 for damages purposes).

Ancillary Measures for Effective Prevention (Article 100(2)):
To ensure the effectiveness of an injunction, Article 100(2) allows the patentee or exclusive licensee, when demanding cessation or prevention of infringement, to also demand other measures necessary for the prevention of infringement. These include:

  1. Disposal of Infringing Articles (侵害の行為を組成した物の廃棄 - shingai no kōi o sosei shita mono no haiki): This can include the destruction of products that were made in infringement of the patent. For patents on a process of manufacturing a product, this extends to the destruction of products made by that infringing process.
  2. Removal of Infringing Equipment (侵害の行為に供した設備の除却 - shingai no kōi ni kyō shita setsubi no jokyaku): This can involve demanding the dismantling or removal of machinery, tools (e.g., molds, catalysts), or factory equipment that was used to carry out the infringing acts.

There are, however, practical limitations. Courts are generally reluctant to order the destruction or removal of equipment or semi-finished products that have substantial non-infringing uses. While Japanese Patent Act Article 100(2) does not contain an explicit limitation like "exclusively used for infringement" (as found, for instance, in some copyright provisions regarding infringing equipment), a similar principle of proportionality applies. These ancillary measures can only be demanded in conjunction with a primary demand for an injunction under Article 100(1). It is understood that because patent rights are time-limited, even infringing articles produced during the patent term cannot typically be ordered destroyed after the patent has expired; the right to demand such disposal is tied to the period during which an injunction against the act of infringement itself is available.

Who Can Sue:
The right to seek an injunction under Article 100 belongs to the patentee and any exclusive licensee. An exclusive licensee has independent standing to sue for injunctions in their own name. Even a patentee who has granted an exclusive license generally retains the right to sue third-party infringers for injunctions, as affirmed by the Supreme Court on June 17, 2005 (in the "Stable Complex Structure Search Method case").

Applicability to Indirect Infringement:
Injunctive relief is also available against acts that are "deemed to be infringement" under Article 101 of the Patent Act (indirect or contributory infringement).

Preliminary Injunctive Relief (Provisional Disposition - 仮処分 Karishobun)

Given that a full trial on the merits for a permanent injunction can be time-consuming, Japanese law provides for preliminary injunctive relief through a "provisional disposition to determine a provisional status" (仮の地位を定める仮処分 - kari no chii o sadameru karishobun). This is a powerful tool for obtaining rapid, interim relief to stop or prevent infringement pending the final outcome of the main lawsuit. These proceedings are governed by the Civil Provisional Remedies Act (Minji Hozen Hō).

Purpose and Grounds for Granting:
The purpose of a preliminary injunction is to provide swift, temporary protection to the rights holder where waiting for a final judgment would lead to irreparable harm. According to Article 23(2) of the Civil Provisional Remedies Act, such a disposition may be granted when it is necessary to avoid "substantial detriment or imminent danger" to the creditor (the patentee in this context) that is likely to arise if the current status quo continues, and which cannot be adequately compensated by monetary damages later.

This requires the applicant (patentee) to demonstrate to the court:

  1. A high probability of success on the merits in the main infringement action (i.e., that the patent is valid and infringed).
  2. An urgent need for interim relief to prevent substantial and irreparable harm.

Key Procedural Differences from a Main Lawsuit:

  1. Standard of Proof (Somai vs. Shōmei): The evidentiary standard for preliminary injunction proceedings is somai (疎明), which means a "prima facie showing" or a degree of proof sufficient to make the asserted facts seem probable. This is a lower standard than the full proof (shōmei) required in a main lawsuit, which demands a high degree of probability, close to certainty.
  2. Security Deposit (担保 - Tanpo): Because a preliminary injunction can significantly impact the respondent's business even before a full adjudication, courts in Japan will almost invariably require the applicant (patentee) to post a security deposit or bond (Article 14, Civil Provisional Remedies Act). This security is intended to cover potential damages that the respondent might suffer if the preliminary injunction is later found to have been wrongfully granted (e.g., if the patent is ultimately found invalid or not infringed in the main action). The amount of security can be substantial and is determined by the court based on the circumstances. If the applicant's prima facie showing is particularly weak, security alone cannot compensate for the lack of evidence.
  3. Expedited Proceedings and Hearings: Preliminary injunction proceedings are designed to be swift. While the Civil Provisional Remedies Act (Article 3) generally does not require full oral arguments for all types of provisional remedies, for those determining a provisional status, like patent injunctions, the respondent must usually be given an opportunity to be heard through a designated hearing date (shinjin kijitsu) or oral argument (Article 23(4)). However, these hearings can be more truncated than in a main action, and in exceptional cases of extreme urgency, the court may even issue an order before hearing the respondent, though this is rare in complex patent matters.
  4. Jurisdiction: The court having jurisdiction over the main patent infringement lawsuit also has jurisdiction over the application for preliminary injunctive relief (Article 12(1), Civil Provisional Remedies Act).

Relationship to the Main Lawsuit:
A preliminary injunction is an interim measure. If it is granted before a main lawsuit on the merits has been filed, the respondent can petition the court to order the applicant (patentee) to initiate the main action within a specified period (Article 37, Civil Provisional Remedies Act). If the patentee fails to file the main lawsuit as ordered, the respondent can seek to have the preliminary injunction revoked.

Impact of Preliminary Injunctions:
Despite being "provisional," a preliminary injunction can have a decisive commercial impact on the respondent, potentially halting their business activities related to the accused product. Consequently, they are not granted lightly. Courts often carefully weigh the patentee's need for urgent relief against the potential harm to the respondent. The granting or denial of a preliminary injunction can also significantly influence settlement negotiations.

Strategic Steps Before Seeking Injunctive Relief

Before initiating legal proceedings for injunctive relief, several preparatory steps are advisable:

  1. Thorough Infringement and Validity Analysis: Conduct a comprehensive analysis to confirm that the accused product or process indeed infringes the Japanese patent and that the patent itself is likely to be held valid if challenged. This involves careful claim construction and a review of relevant prior art.
  2. Warning Letter (警告状 - Keikokujō): Issuing a carefully drafted warning letter to the alleged infringer is often a prudent first step.
    • It puts the alleged infringer on notice of the patent and the infringement claim.
    • It can be useful for establishing knowledge, which may be relevant for certain types of damage claims or aspects of indirect infringement.
    • It may be a prerequisite for claiming provisional monetary protection under Article 65 of the Patent Act if the application is only published and not yet granted.
    • Caution: Warning letters must be factually accurate and legally sound. Baseless or overly aggressive warning letters, especially if widely disseminated, can potentially lead to counterclaims against the patentee, for example, under the Unfair Competition Prevention Act for trade disparagement if the infringement allegations are found to be false.
  3. Evidence Gathering: Collect as much evidence as possible regarding the infringing activity and the structure/operation of the infringing product or process.
    • Evidence Preservation Procedures (証拠保全手続 - Shōko Hozen Tetsuzuki): If there is a risk that crucial evidence might be destroyed, altered, or concealed before it can be examined in a main lawsuit, the patentee can apply to the court for an evidence preservation order under Article 234 of the Code of Civil Procedure. This can involve, for example, a court-supervised inspection of the alleged infringer's premises or products.
    • Pre-litigation Evidence Gathering Dispositions: Article 132-4 of the Code of Civil Procedure allows for certain evidence gathering measures even before a lawsuit is filed, such as requesting expert opinions or an inspection by a court bailiff, though these are reportedly used less frequently in patent cases.

Key Considerations in Injunction Proceedings

  1. Patent Validity Defense (Article 104-3): In Japan, even in an infringement lawsuit (whether for a permanent or preliminary injunction), the defendant can argue that the patent is invalid and therefore unenforceable. Under Article 104-3 of the Patent Act, if the court is convinced that the patent "should be invalidated by a patent invalidation trial" (e.g., due to lack of novelty or inventive step), it will deny injunctive relief and damages. This means that the strength of the patent's validity is a critical factor in any injunction proceeding.
  2. Balancing of Hardships and the Abuse of Rights Doctrine: While a finding of valid patent infringement generally leads to an injunction, Japanese courts, particularly the IP High Court, have shown a willingness to consider equitable factors and the doctrine of "abuse of rights" (kenri no ran'yō) in exceptional circumstances. A notable example is the IP High Court Grand Panel decision of May 16, 2014 (in an Apple v. Samsung dispute), where a request for a preliminary injunction based on a Standard Essential Patent (SEP) subject to Fair, Reasonable, and Non-Discriminatory (FRAND) licensing commitments was denied on the grounds that seeking an injunction in that specific context constituted an abuse of rights. This indicates that while injunctive relief is a strong remedy, it is not entirely absolute and can be subject to overriding equitable considerations, somewhat analogous to the four-factor test for permanent injunctions in the U.S. following eBay Inc. v. MercExchange, L.L.C., though the underlying legal doctrines differ.

Enforcement of Injunctions

If an injunction (either preliminary or permanent) is granted and the infringer subsequently violates its terms, the patentee can seek court enforcement. For prohibitory injunctions (orders not to do something), enforcement is typically through indirect compulsion (Article 172, Civil Execution Act). This involves the court ordering the infringer to pay a certain amount of money to the patentee for each day of non-compliance or for each infringing act, thereby creating a strong financial disincentive to violate the injunction. If the injunction includes orders for positive actions, such as the disposal of infringing goods or removal of equipment, and the infringer fails to comply, the patentee may seek alternative execution (Article 171, Civil Execution Act), where the court authorizes the patentee or a third party to carry out the required actions at the infringer's expense.

Conclusion

Japan provides patentees with potent tools for seeking injunctive relief against infringement. Article 100 of the Patent Act forms the basis for permanent injunctions and related preventive measures in a main lawsuit, importantly without requiring proof of the infringer's fault. For more urgent situations, the Civil Provisional Remedies Act allows for expedited preliminary injunctions, provided the patentee can make a prima facie showing of their rights and the necessity for interim relief, often coupled with the requirement of a security deposit. The robust invalidity defense available under Article 104-3 means that the strength of the patent's validity is intrinsically linked to the prospects of obtaining an injunction. For U.S. rights holders, successfully leveraging these mechanisms requires a strong underlying case, careful strategic planning, and expert navigation of Japanese legal procedures.