The Japanese legal system covers two types of intellectual property rights in relation to the protection of inventions: patent rights and utility model rights. Both systems are based on statutory laws, namely the Patent Act and the Utility Model Act.

Patents

The Patent Act employs a substantive examination principle for the patent grant procedure. A patent application must first be filed with the Japan Patent Office (JPO) to obtain a patent right for an invention. A request for examination must also be filed within three years from the date of filing the patent application, or the patent application will be deemed withdrawn.

A JPO examiner conducts an examination to determine whether the patent application satisfies all requirements under the Patent Act.

• If the examiner finds any reason for rejection, a notice of reason for rejection will be issued. An applicant who has received a notice of reason for rejection will be given the opportunity to file a written argument and/or an amendment in response to that rejection.
• If the examiner finds no reason for rejection in the patent application or finds that the rejection has been overcome, they will issue a decision to grant a patent for the patent application. A patent will be granted once the applicant pays the registration fees for the first three years.

Utility Models

In contrast to patent applications, the Utility Model Act does not require a substantive examination for applications for utility model registration (ie, for all applications that have passed formal examinations); the utility model right will be automatically registered without a substantive examination. The registration fees for the first three years must be paid at the time of filing the utility model application.

Patents

According to statistics issued by the JPO, the average period from filing a request for examination to the issuance of a final decision (either granting or rejecting) was 13.0 months in 2024. Also, the average grant rate was 76.3% in 2024.

Domestic applicants do not need representation in order to initiate grant proceedings, but foreign applicants do. The typical costs incurred from filing to grant are USD8,000, comprising official fees of USD1,500 and lawyers’ fees of USD6,500. The official fees vary depending on the number of claims. Also, additional fees for translating certain documents (eg, the specification and notice of the reason for rejection) may be incurred where necessary.

Utility Models

The typical costs incurred from filing to grant are USD2,000, comprising official fees of USD200 and lawyers’ fees of USD1,800. The official fees vary depending on the number of claims. Also, additional fees for translating certain documents (eg, the specification) may be incurred where necessary.

Patents

The term of a patent right is 20 years from the date of filing the patent application. There are, however, some exceptions:

• if the establishment of a patent right is registered on or after the date on which five years have passed since the date of filing of the patent application or the date on which three years have passed since the date of filing of a request for examination of the application, whichever is later (the “base date”), the term may be extended by the period calculated by deducting a certain period from a period equivalent to the base date until the date of registration of establishment of the patent right; and
• the term may be extended by up to five years on request if the invention cannot be used due to the time spent obtaining approval or any other dispositions under a law intended to ensure safety, as prescribed by a Cabinet Ordinance.

Utility Models

The term of a utility model right is ten years from the date of filing the utility model application. A utility model application or right may be converted to a patent application within three years from the date of filing the utility model application.

Both patent and utility model owners have the right to an injunction, claim damages, and claim for unjust enrichment. Also, patent and utility model owners are obligated to pay annual renewal fees to maintain their rights.

Notably, a substantive examination is not required for utility model registration applications. As a result, a utility model owner can only enforce their rights against an infringer after issuing a warning and providing a Utility Model Technical Opinion Report for the registered utility model. This report assesses the novelty and inventive step of the registered utility model, conducted by a JPO examiner based on a search of prior art documents. A request for a Utility Model Technical Opinion Report can be made at any time after the application for a utility model has been submitted.

In Japan, there is no publicly available list of applicable patents for certain products or processes. Although there is a public database of patent information in Japan called J-PlatPat, J-PlatPat does not have any functions to search applicable patents in relation to certain products or processes.

In Japan, the patent linkage system is not established by statute but operates through administrative practice under a ministry notice issued by the Ministry of Health, Labour and Welfare (the “MHLW”). It essentially consists of two stages. First, marketing approval for a generic drug will not be granted if a patent exists for the active ingredient, or if certain indications or dosage regimens remain under patent, approval will be limited to the unpatented uses. Second, after approval and before price listing, the notice requires the generic manufacturer to hold a “prior consultation” with the patentee whenever any patent-related concern arises, to address those concerns and confirm a stable supply of the generic product upon market entry.

Unlike the U.S. Orange Book system, Japan has no official mechanism for publishing drug-related patents. In the first stage, the MHLW bases its decision on patent information voluntarily submitted by the originator; information not submitted will not be considered. The MHLW does not have the authority to make substantive determinations on patent infringement or validity. Nevertheless, its approval decisions inevitably affect the exercise of patent rights. Recognising this, the MHLW is introducing a new system in a pilot, announced in a recent ministry notice issued in November 2025, under which the MHLW may seek the views of a specialised advisory committee to incorporate expert opinions on pharmaceutical patents when reviewing generic or biosimilar drug applications for approval. The ministry’s notice regarding the patent linkage system mentioned above was also updated in October 2025 to clarify certain long-standing practices, including its application to biosimilars. As such, discussions around Japan’s patent linkage system are ongoing, and its future development deserves close attention.

There is no further protection for technical intellectual property rights after their maximum term has lapsed.

Anyone may file a third-party observation at any time after filing a patent application or an application for utility model registration, even after a patent or utility model right has been granted. Third-party observations may include prior art information or a submitter’s comments regarding the novelty or inventive step of the claimed inventions, as well as other information or comments regarding other requirements, such as the addition of new matter, the support requirement, or the enablement requirement. Third-party observations may be filed anonymously.

Patents

An applicant may file an appeal with the JPO against a rejection decision issued by a JPO examiner. A panel of three appeal examiners will then review the patent application to determine whether the rejection decision was appropriate.

When filing an appeal against the rejection, the applicant can amend the claims, specifications, or drawings. If any amendments are made, the application will first be re-evaluated by the initial examiner who issued the rejection decision before it is sent to the appeal board.

If the initial examiner finds that the amended application has been sufficiently improved, they may issue a decision to grant the application without further involvement from the appeal board. However, if the initial examiner still believes the application should be rejected, it will be forwarded to the appeal stage for examination by the panel of appeal examiners.

Utility Models

No remedy is available or applicable for utility model applications because the Utility Model Act does not require a substantive examination for the granting of a utility model right.

Patent or utility model owners who miss the annual fee deadline may still pay late by remitting both the annual fee and an equal surcharge within six months after the deadline expires.

Furthermore, if the patent owner or the utility model owner is unable to meet the payment deadline, they can still make an additional payment to restore the patent right or the utility model right, except in the case of a “willful” failure to meet the payment deadline. This additional payment can be made within two months of the applicant’s ability to make the payment or within one year after the payment deadline, whichever comes first.

Both patent and utility model owners may file a request for a trial to correct the description, the scope of the claims or the drawings attached to the application.

The purpose of the correction is limited to the following:

• restriction of the scope of claims (including deletion of claims);
• correction of errors or incorrect translations;
• clarification of ambiguous statements; and/or
• dissolution of the claim citation relationship.

The correction cannot be made beyond the scope of the matters disclosed in the description, the scope of claims or the drawings attached to the application.

Utility model owners are allowed to make a request for correction only once, except for the deletion of claims, whereas patent owners may request a trial for correction as many times as they wish, except where the patent has been invalidated by an invalidation trial or revoked by a patent opposition. Patentees may not request a correction while a patent opposition or invalidation proceeding is pending but may instead request a correction in the proceedings of the patent opposition or patent invalidation trial.

If the owner of a technical intellectual property right (eg, a patent) finds that a third party is infringing upon their patent, they can take one or more of the following actions:

• commence a regular patent infringement suit with a District Court;
• file a petition for a preliminary injunction with a District Court;
• file an import suspension application with the Customs Office; or
• use alternative dispute resolution proceedings, such as mediation or arbitration, if the other party agrees.

Only an interested person may file a request for a trial on patent invalidation. The term “interested person” means a person who has, or potentially will have, their legal interest/standing directly affected by the existence of the patent right. Conversely, in the Patent Opposition System, any person (not limited to interested persons) may file an opposition to a patent within six months of the publication date of the Gazette containing the patent.

The Japanese Patent Act also provides for three types of non-exclusive licences granted by the JPO Commissioner’s award (eg, compulsory licences). In 2021, a request for a compulsory license was filed for Japanese Patent No 6518878, marking the first time a council was convened in Japan to address such a request. However, in 2024, the parties reached a settlement, resulting in the withdrawal of the request. As of the end of 2025, no compulsory license has been granted in Japan.

The Tokyo and Osaka District Courts have exclusive jurisdiction over first-instance patent and utility model rights litigation. The court where a plaintiff should file a lawsuit depends on the defendant’s corporate address and the location of the infringing activity. The Japanese Intellectual Property High Court (IPHC) has exclusive jurisdiction over appeals from District Court decisions. The IPHC is a special branch of the Tokyo High Court. Parties may appeal the IPHC’s decisions to the Supreme Court.

The Japan Intellectual Property Arbitration Centre (JIPAC) provides alternative dispute resolution services, including mediation and arbitration, in the field of intellectual property. In addition, the International Arbitration Centre in Tokyo (IACT) – an international arbitration organisation expected to provide dispute resolution services – commenced operations in September 2018.

There are no statutory prerequisites for filing a lawsuit. However, as patent rights and registered exclusive licences become effective upon the establishment of registration with the JPO, such registration will be required when a patentee or registered exclusive licensee brings a claim for damages and/or an injunction based on that patent right or registered exclusive licence. It is, however, generally considered that such registration will not be required when a non-registered exclusive licensee brings a claim for damages based on a non-registered exclusive licence.

In Japan, a party may choose at their own discretion whether to have legal representation. However, in practice, it is common for lawyers to represent parties in intellectual property matters. Patent lawyers can also represent parties for certain intellectual property cases under certain conditions.

In Japan, preliminary injunctions are available in cases where such injunctions are necessary to prevent a rights owner from incurring substantial detriment or an imminent danger with respect to the rights in dispute. If a request for a preliminary injunction is granted, the rights owner will usually be required to deposit a certain amount of money as security. The court will determine the amount of that security in consideration of the circumstances of the specific case. A relatively large amount of money may be required to be deposited as security.

As the preliminary injunction substantially achieves an injunction against the other party’s conduct before the lawsuit is finalised, in a preliminary injunction case, a hearing of both the rights-owner and the other party is required, and prima facie evidence of a similar level to the proof required in the lawsuit is often required. In general, preliminary injunctions are intended to resolve disputes more quickly than litigation; however, the speed of trial is often not so different from that of litigation because of the need for prima facie evidence, as mentioned above.

A potential defendant can file a request for a patent invalidation trial before the JPO and/or initiate a lawsuit for a declaratory judgment to confirm the absence of the right to demand an injunction, etc. There is no need for a potential opponent to lodge a protective brief in order to take these actions. It should be noted that a potential opponent is not entitled to require the owner to post a bond under the Civil Preservation Act, but a court usually orders the owner to deposit a certain amount as security when issuing an interim injunction order.

There are no special limitations applicable only to intellectual property matters.

Claims for injunctions based on patent rights may be filed at any time if infringement of the patent rights exists or a threat of infringement of the patent rights is recognised.

The claim for compensation for loss or damage by the tort of patent infringement is extinguished by prescription if the right is not exercised within three years from the time when the patentee comes to know the damage and the identity of the infringer or if the right is not exercised within 20 years from the time of the tortious act, pursuant to the provisions of the statute of limitations provided in the Civil Code of Japan, which is a general law. Please note that the above prescription period may be renewed, or the expiry of the prescription period may be postponed for statutory reasons.

Although there is no discovery procedure in Japan, the Patent Act provides that a court can order a party to produce documents upon the other party’s request for the purposes of:

• proving infringing activities if prima facie evidence of such infringing activities is provided; or
• calculating damages if the court tentatively concludes that intellectual property rights infringement has been established.

However, this will not apply where the accused infringer possessing the documents has reasonable grounds to refuse to produce them.

If the court needs to assess whether reasonable grounds exist, it may require the document holder to present them for in-camera review. Furthermore, on 1 July 2019, the amended Patent Act introduced a procedure in which the court can determine the necessity of document production by way of in-camera procedures. The amended Patent Act also introduced a procedure allowing expert advisers to participate.

Moreover, by way of the 2019 amendment to the Patent Act, an inspection system was introduced on 1 October 2020, under which an inspector designated by the court will be entitled to enter into the factories, offices, etc, of a defendant and collect evidence necessary to make a decision on the existence of facts regarding the alleged infringement. However, the requirements for conducting an inspection are strictly stipulated as follows:

• it can be deemed that it is necessary to collect evidence (necessity);
• there are reasonable grounds for suspecting the existence of patent infringement conducted by the adverse party (probability);
• it is expected that no other means can be utilised to collect evidence (replaceability); and
• it is not considered inappropriate to conduct an inspection due to an inappropriate burden being placed on the adverse party or any other circumstances (appropriateness).

A complaint must contain both parties’ names and addresses, the plaintiff’s lawyer’s name and address (if appointed), the gist of the demand and the grounds for the demand. Specifically, the complaint must detail each accused product and alleged infringing act, describe the product’s relevant features, and compare them to each claim element. In general, supportive evidence – to prove both the act of infringement and the relevant features of the product – is submitted with the complaint. A patentee is expected to conduct a sufficiently detailed investigation and analysis of a case prior to initiating a lawsuit to identify these facts and find the relevant evidence.

No special provisions for lawsuits in intellectual property proceedings differ from those for non-intellectual property proceedings.

It is acceptable to supplement pleadings with additional arguments. A court examines the case through periodic hearings (generally once a month), and each party is allowed to present its legal/factual arguments or evidence during these proceedings. The plaintiff may even expand or amend the claim or statement of claim until oral arguments are concluded. However, the courts may limit such additional arguments or evidence if they consider that they would substantially delay court proceedings.

The legal system does not allow for representative or collective actions for intellectual property rights proceedings, although if the subject matter of the suits is common to two or more persons or is based on the same factual or statutory cause, these persons may sue or be sued as co-parties.

Civil Code

As an abuse of rights is prohibited under the Civil Code, the same will apply to the execution of patent rights, and therefore, where the execution of such rights is abusive, that execution will be restricted.

For example, the act of filing a lawsuit may cause tort liability where such litigation is found to be significantly unreasonable in light of the purport of the litigation system (eg, the allegation of infringement is entirely baseless and the owner of the intellectual property right is fully aware of the lack of legal grounds). In addition, based on judicial precedents, a patent right-holder who has made a declaration of fair, reasonable and non-discriminatory (FRAND) terms will not be permitted to claim for an injunction or for licence fees against a party who intends to be licensed under FRAND terms beyond those terms, as this will fall under an abuse of rights.

Guidelines for the Use of Intellectual Property

In addition, the Japan Fair Trade Commission (JFTC) has stipulated that its Guidelines for the Use of Intellectual Property (IP Guidelines) under the Antimonopoly Act clearly set out the principles governing the use of intellectual property rights, including patent rights, under the Act. In January 2016, the JFTC partially amended the IP Guidelines and supplemented the descriptions related to standard essential patents under the Antimonopoly Act. If a patent right is exercised in a manner that violates these Guidelines, the act may constitute a violation of the Antimonopoly Act.

Unfair Competition Prevention Act

Furthermore, if the owner of the intellectual property right makes or disseminates a false allegation of infringement of that intellectual property right, that act could constitute an act of unfair competition under the Unfair Competition Prevention Act, and the owner of the intellectual property right may be subject to a claim for injunction and/or damages.

A patent owner and an alleged infringer are usually the necessary parties to patent infringement litigation. A registered exclusive licensee is entitled to file an action without the patent owner, based on an infringement of the registered exclusive licence, seeking the same remedies as the patent owner. In this regard, there are arguments over whether non-exclusive or non-registered exclusive licensees can initiate an action for infringement.

Regarding injunctions, it is generally understood that neither a non-registered exclusive licensee nor a non-exclusive licensee has the right to seek an injunction. However, when it comes to claims for damages, a non-registered exclusive licensee can pursue such claims, while a non-exclusive licensee is not permitted to seek damages.

For a direct infringement to be constituted, the product in question needs to satisfy all of the component features of a patented invention. If any one of the constituent features is not satisfied, a direct infringement has not been constituted.

However, even if the product does not satisfy all the component features, the following cases will constitute indirect infringement and thus constitute patent right infringement.

• an act of the accused infringer producing, for instance, a product to be used exclusively for making a product of a patented invention, or a product to be used solely for the use of a patented invention;
• an act of the accused infringer producing a patented invention or a product that is to be used exclusively for the use of a process of a patented invention (excluding those widely distributed within Japan) and which is indispensable for that invention’s resolution of the problem, knowing that the invention is a patented one and that the product is used for the working of that invention; and
• an act of the accused infringer possessing for assignment, etc, or exporting a product of a patented product or a product that is produced by using a process of a patented invention.

In any instances where direct or indirect infringement is constituted, a patentee may claim injunctions and damages against an infringer. In a claim for damages, provisions such as those on the presumption of the amount of damage or those on the presumption of negligence may be applied.

In the Japanese Patent Act, inventions are classified as:

• the invention of a product;
• the invention of a process;
• or the invention of a process for producing a product.

An act of working on a patented invention is stipulated for each of these categories. Specifically, for the invention of a process, the act of using the process is specified as an act of working.

Additionally, for an invention that involves a process for producing a product, the following activities are considered acts of working:

• using the process; as well as
• producing, using, assigning (including lending and providing via telecommunications lines), exporting, importing, or offering to assign the product created by that process.

Conversely, for an invention that pertains to a product, the acts of producing, using, assigning (including lending and providing via telecommunications lines), exporting, importing, or offering to assign the product itself are defined as acts of working.

No clear rule exists regarding whether patent infringement in Japan can be recognised when part of a process is executed abroad. In some cases where steps of a patented process were conducted outside Japan, a District Court ruled that this cannot be considered working the patent in Japan because the relevant technical steps of the patent are not completed within the country. However, this ruling is not regarded as a well-established precedent that applies universally to process inventions in Japan.

In principle, the scope for protection of a patent right (eg, the technical scope of a patented invention) is determined based on the statements in the scope of claims. In addition, the meaning of each term used in the scope of claims is interpreted in conjunction with the statements in the description and drawings. The prosecution history of the application and prior art may also be considered. Accordingly, to say that infringement of a patent right has taken place in principle, the subject product must satisfy all of the constituent features of the patented invention. However, even if the product does not satisfy all of the constituent features of the patented invention, there may be a case that amounts to indirect infringement or infringement under the doctrine of equivalents (see 3.2 Direct and Indirect Infringement).

Typical defences against an allegation of patent infringement include non infringement arguments and assertions of invalidity as a counter argument in the litigation, as well as the following.

If a patent right is exercised abusively, it can lead to certain defences for the accused party. For example, if a patent holder who has declared their commitment to FRAND (fair, reasonable, and non-discriminatory) terms later seeks an injunction against a party that intends to be licensed under those terms or demands damages exceeding what would normally be considered a fair licensing fee, the defendant may invoke the defence of abuse of rights.

If the defendant has practised a patented invention or prepared for such practice at the time of the patent application filing, the defendant can claim “prior use” as a defence.

If the patentee, when filing an application, makes assertions that exclude the technology that is to be included in the technical scope of a patented invention (based on the common meaning of the term being used), it is typical for the technical scope of the patented invention to be construed in a limited manner as a result.

Where the products in question were assigned from a patentee or person with legitimate rights, no patent infringement will be admitted, as the patent right will have been exhausted.

In addition, the defendant may claim that their use of the patented invention was experimental and, therefore, beyond the scope of the patent right.

Even though the Patent Act provides for three types of non-exclusive licences to be granted by the JPO Commissioner (eg, compulsory licences), as of the end of 2025, no such compulsory licence has ever actually been granted in Japan (see 2.2 Third-Party Remedies to Remove the Effects of Intellectual Property).

The fact that the defendant’s infringing conduct was an exercise of their patent right cannot be used as a defence against the patentee’s infringement claim.

As to the statute of limitations, the patentee cannot claim damages for an infringement if more than three years have passed since the date on which the patentee became aware of an infringement and the identity of the infringer who caused the damage. There is an overall limit of 20 years from the act of infringement (see 2.9 Special Limitation Provisions).

Experts involved in patent litigation are mainly judicial research officials and expert advisers.

Judicial research officials are full-time court employees who conduct examinations on technical matters necessary for judicial decisions and report to a judge. Judicial research officials are primarily appointed from the pool of JPO employees or patent lawyers.

Expert advisers are part-time employees appointed by the courts who get involved in proceedings to:

• arrange issues and evidence;
• examine evidence; and
• enter into a settlement in the court proceedings.

Expert advisers are usually involved in proceedings to arrange issues and evidence (preparatory proceedings, etc) and make oral explanations on technical matters. In patent litigation, to gain a proper understanding of technical issues, expert advisers are often involved and conduct technical explanation sessions during preparatory proceedings. It is common for an expert in the technical field to which a patented invention belongs (usually a university professor or patent lawyer) to be appointed as an expert adviser.

In addition, in litigation, experts selected by a party may prepare expert opinions, which are submitted as evidence by the party but rarely testify in court as witnesses.

There is no separate procedure for claim construction in Japan.

A system allowing the court to seek third-party opinions in patent infringement lawsuits was introduced on 1 April 2022. According to Article 105.2-11 of the Patent Act, if a party requests it and the court finds it necessary, the court may request the public to submit documents stating public opinions on the application of the Patent Act or any other necessary matters after hearing the other party’s opinion. It is envisioned that this system will be used in patent infringement cases where the judgments may have significant impacts not only on an industry to which the parties belong but also on companies in other industries.

Case No 2018 (Ne) 10046

In the recent Case No 2018 (Ne) 10046, the Intellectual Property High Court issued a request for third-party opinions for the first time. In this case, the patent at issue claimed a certain system comprising a server and a plurality of terminal devices. The issue here was whether or not the defendant’s act of creating a new system can be considered “production” (a form of working of invention as defined in Article 2(3)(i) of the Patent Act) of the patented system, even when the server in the alleged infringing system is located outside Japan. The court issued the request for third-party opinions regarding whether the defendant’s act can be considered “production” of the patented system and, if so, what requirements are necessary for it to fall under the category of “production”. Various organisations have submitted multiple statements in response to the court’s request for opinions. The IP high court eventually determined infringement in its judgment, whereas the district court, in the first instance, denied the “working of invention” within Japan.

Case No 2023 (Ne) 10040

The latest case in which the Intellectual Property High Court issued a request for third-party opinions is Case No 2023 (Ne) 10040, which concerns a patented invention for a breast augmentation composition containing multiple drug substances. According to Article 69(3) of the Patent Act, the effect of a patent right for an invention related to “a pharmaceutical product to be produced by mixing two or more drugs” does not extend to “acts of preparation performed based on a prescription by a physician or dentist.”

In this case, the court has requested third-party opinions, such as whether the act of a nurse or assistant nurse mixing multiple drugs to produce a combined medication, as instructed by a physician without issuing a prescription, can constitute an “act of preparation performed based on a prescription by a physician or dentist”.

Patents

There are two procedures available for seeking the revocation/cancellation of a patent – namely, an opposition or an invalidation trial before the JPO.

Anyone may file an opposition within six months from the issue date of a patent Gazette based on the following grounds:

• violation of requirements for patentability, such as novelty, inventive step, double patenting, etc;
• the addition of new matter;
• violation of description requirements; and
• violation of a treaty.

An interested party may file an invalidation trial at any time after a patent has been granted, even if it has expired, based on the following grounds:

• violation of requirements for patentability, such as novelty, inventive step, double patenting, etc;
• addition of new matter;
• violation of description requirements;
• violation of a treaty;
• the patent having been granted on a patent application filed by a person who is not the inventor and who has not succeeded in the right to obtain a patent for the invention; and
• the correction of the description, scope of claim or drawings attached to the application for the patent having been obtained in violation of the provisions under the Patent Act.

Utility Models

There is only one procedure for revocation/cancellation of a utility model registration: an invalidation trial before the JPO.

An interested party may file an invalidation trial at any time after a utility model has been granted, even after the utility model has expired, based on the following grounds:

• violation of requirements for registration as a utility model, such as novelty, inventive step, double patenting, etc;
• the addition of new matter;
• violation of description requirements;
• violation of a treaty;
• the utility model having been granted on a utility model application filed by a person who is not the inventor and who has not succeeded in the right to obtain a utility model for the invention; and
• the correction of the description, scope of claims or drawings attached to the application for the utility model having been obtained in violation of the provisions under the Utility Model Act.

In Japan, an opposition or an invalidation trial for a patent or a utility model registration may be filed for each individual claim.

Amendments (“corrections” in opposition or invalidation proceedings under the Patent Act or the Utility Model Act) may be filed in opposition or invalidation proceedings.

In opposition proceedings, a patent owner may file amendments in the period for responding to a notice of cancellation issued by the board of trial examiners who examined the request for opposition.

In invalidation trial proceedings, the owner of a patent or utility model right may file amendments in the period for filing an answer in response to a request for an invalidation trial. The owner may also file amendments in the period for responding to a notice of reasons for invalidation or an advance notice of appeal decision, both issued by the board of trial examiners who examined the request for invalidation trial.

In patent or utility model infringement litigation heard before the courts, both infringement and invalidation issues may be heard together because the defendant may challenge the validity of a patent or utility model registration as a defence before a court. The courts examine both infringement and validity together and render a decision based on their examination.

There are no specifically applicable provisions regarding trial and settlement in intellectual property rights proceedings. However, in practice, the trial will be divided into two parts. At the first stage (the examination of infringement), the court focuses on determining whether the infringement of the intellectual property right is established. At the second stage (the stage for examination of damages), a court will assess the damages incurred by a plaintiff only after it has tentatively concluded the establishment of the infringement.

In this regard, the Intellectual Property Division of the Tokyo District Court has a trial model for patent infringement litigation. According to this trial model, it is assumed that six court hearing dates are held at the first stage (stage for examination on infringement). If courts find no patent infringement, they will either:

• make recommendations for settlement after disclosing their opinions; or
• conclude oral arguments and render judgments.

If courts find that there is patent infringement, the courts will either:

• make recommendations for settlement after disclosing their opinions; or
• proceed to the second stage (the stage for examination of damages).

It is assumed that three court hearing dates are held at the second stage, and both parties present arguments and counterarguments with regard to the amount of damages. Then, the courts will either:

• conclude oral arguments and render judgments after forming final opinions on the amounts of damages; or
• make recommendations for settlement after disclosing their opinions.

However, as the progress of trials (including the number of court hearing dates) depends largely on the complexity of cases, trials rarely proceed as envisioned in the above trial model – and in complex cases, trials are often prolonged for much longer than the trial model.

According to statistics provided by the Intellectual Property High Court, the average time intervals from commencement to disposition in intellectual property-related civil cases in 2024 were 14.5 months (in all district courts) and 7.1 months (in all high courts).

In patent litigation, examination of fact witnesses or experts is rarely conducted. In cases of examination of witnesses, opportunities for cross-examination are provided.

A case is determined solely by a legal judge. The Japanese legal system has neither technical judges nor jury trials for intellectual property cases.

At the Tokyo and Osaka District Courts, there are special divisions for intellectual property matters (four at the Tokyo District Court and two at the Osaka District Court), where judges experienced in intellectual property matters hear and decide cases. The judges in these courts and the IPHC do not necessarily have technical backgrounds; the courts retain judicial research officials with technical backgrounds to help judges understand any technology issues involved in a case (see 3.6 Role of Experts). The courts can also appoint and request expert advisers to assist judges with any case involving advanced, complicated or specialised technology issues.

Parties cannot influence who will judge a case, although a party can request to avoid a certain judge if they have reason to believe that said judge cannot be impartial due to a particular relationship with the other party (eg, being a relative of one party).

A judge usually takes the initiative in settlement negotiations unless the parties clearly refuse to settle a case. In no event will a defendant be obliged to settle a case. Generally, courts prefer settlements rather than judgments to resolve cases. A judge may disclose or imply their unofficial, tentative opinion on a case to the parties in order to facilitate settlement negotiations. A judge will cease settlement negotiations if one party decides to request a court decision rather than a settlement.

Even if there are any pending parallel revocation or infringement proceedings, the current proceedings will not normally be stayed, and the courts will make a separate judgment in each case. The courts can even dismiss a claim for infringement on the grounds that the patent is invalid, without the need for a revocation proceeding. Therefore, it is possible for a conflict between two cases on the same subject matter to exist. However, in practice, the High Court, as the court of the second instance, will make consistent judgments so that any contradiction in the first instance will be resolved.

There have been no cases in Japan in which anti-suit injunctions have been issued against litigation and it is unclear whether Japanese courts would take foreign anti-suit injunctions into account. In addition, in Japan, there is no statutory basis for granting injunctions against litigation by patentees, and there have been no examples of Japanese courts recognising anti-suit injunctions.

Remedies Available for the Patentee

Typical remedies available to a patentee include injunctive relief and damages. As part of injunctive relief, the patentee can request necessary measures to prevent further infringement, which may include the disposal of the infringing goods. While lawyers’ fees can be recovered as part of the damages, this recovery is quite limited – typically around 10% of the total amount of actual damages awarded by the courts.

A patentee is only entitled to seek compensatory damages, as claims for enhanced damages, such as punitive damages, are not permitted, even in cases of willful infringement. The Patent Act establishes certain presumptions for calculating damages based on the profits generated from the infringement or the expected royalties. Ultimately, a judge has the discretion to determine the appropriate remedies or the amount of damages, but this discretion is limited to the amount claimed by the plaintiff.

In addition, where an applicant has given a warning, together with documents stating the contents of the invention claimed in the patent application, that applicant may also claim compensation equivalent to the licence fee against any person who has worked the invention as a business after the warning and before the registration of the patent. Furthermore, even without such a warning, the applicant may claim compensation against those who, while aware that the invention relates to a published patent application, have worked the invention as a business before the registration. The right to claim compensation may only be exercised after the patent has been registered.

A patentee may also demand measures necessary to restore its business credibility, but this remedy is rarely used.

Enforcement of Remedies

The methods for the enforcement of remedies depend on the contents of those remedies. For example, with respect to judgments ordering patent infringers to pay damages, the remedies are enforced by seizing the infringers’ property and receiving dividends from proceeds from auctions, etc. With regard to judgments ordering patent infringers to cease and desist from manufacturing the infringing products, if the infringers do not perform the obligations ordered in the judgment, the court in charge of enforcement will enforce the remedies by ordering the infringers to pay to the obligees certain amounts of money which are found to be reasonable for securing performance of the obligation.

If a defendant prevails, the courts can order the plaintiff to pay court costs (eg, transportation fees to attend court hearings, expenses for delivering documents and daily allowances for witnesses); however, such costs do not include the defendant’s legal fees or other costs incurred by the defendant in the course of the procedure. There is no right or remedy for a prevailing defendant to recover their own costs.

A prevailing defendant may seek damages arising out of the infringement litigation, including their lawyers’ fees if the litigation itself is considered to constitute a tort on the grounds that it is found to be unreasonable (eg, if an allegation of patent infringement is entirely baseless and the patentee is fully aware of the lack of legal grounds). However, the courts rarely accept such a claim.

There are no different remedies for different types of technical intellectual property in Japan.

In an effort to stop the execution of an injunction granted at first instance, an infringer will (upon filing an appeal) have to file a petition to seek a ruling on the suspension of compulsory execution. Here, the infringer will need to provide a security deposit (to be returned after litigation).

Under Japanese law, injunctions are enforceable pending appeal. However, in practice, when infringers file an appeal, they also file a motion for suspension of compulsory execution in most cases, and such suspensions are usually granted if the motion is filed.

The above refers to judgments for injunctions of the first instance in main lawsuits. On the other hand, if right-owners request preliminary injunctions separately from (or in parallel with) the main lawsuits and the first instance courts grant the requests and issue preliminary injunction orders, it is difficult to stop enforcement of such preliminary injunction orders in practice, although there is a legal way to challenge such preliminary injunction orders (see 2.7 Interim Injunctions).

Generally, there are no special provisions concerning the appellate procedure for patent litigation. However, the IPHC has exclusive jurisdiction over appeals from decisions made by the Tokyo District Court and the Osaka District Court on patent litigations. A court normally consists of three judges, but if the case includes an important issue of law, five judges may sit to consider the matter and deliver their opinion.

As the court of the second instance, the IPHC reviews not only issues of law but also the facts from the proceedings in District Courts in the first instance. The IPHC may also conduct its own factual findings. A party may submit additional legal arguments, facts or evidence to the appeal court, unless such an additional claim is considered to be causing delay to the procedure and to be that party’s fault. However, the Supreme Court, as the court of final instance, only reviews the legal issues of a case.

With respect to patent infringement litigation in Japan, costs normally incurred are for:

• investigating a product or method;
• conducting searches for prior art references;
• sending warning letters; and
• preparing for litigation.

Stamp fees and expenses for delivering documents are required in order to file a lawsuit in Japan. The amount of stamp fees is calculated according to a formula prepared by the court based on the value of the subject matter of the suit.

In general, the losing party typically pays court costs – including stamp fees, expenses for delivering documents, and daily allowances for witnesses. However, the allocation of these costs is at the court’s discretion. The court may also assign a portion of the costs to the winning party based on the extent to which their claims were not accepted.

It should be noted that court costs do not include lawyers’ fees, and thus, generally speaking, each party must bear its own lawyers’ fees. A plaintiff may seek compensation for their lawyer’s fees as part of damages, but the recovery rate is left to the court’s discretion and is usually quite limited, even if the plaintiff wins the case (in practice, around 10% of the total amount of actual damages admitted by the courts).

Alternative dispute resolution (ADR) is not commonly used to settle intellectual property cases in Japan. However, ADR, such as mediation or arbitration, is available, and JIPAC and IACT (see 2.4 Specialised Bodies/Organisations for the Resolution of Disputes) are the ADR organisations that provide dispute resolution in the field of intellectual property.

Moreover, the Tokyo District Court and the Osaka District Court introduced mediation procedures for IP rights matters on 1 October 2019. This procedure is designed to resolve disputes regarding IP rights matters in a speedy and efficient manner by using a mediation committee composed of a judge from the special division for intellectual property matters and experts, such as lawyers or patent attorneys, who orally express their opinions. In principle, the procedure should be concluded within around three hearing dates.

Patent rights may be freely assigned. However, no assignment will take effect unless it has been registered in the patent registry, except in cases of general succession, such as inheritance or merger. Where a patent right is jointly owned, no joint owner may assign their share without the consent of all the other joint owners. Neither an agreement in writing nor JPO approval is required to conduct an assignment.

Assignment of a patent right takes effect upon registration in the patent registry. In the case of a general succession, such as through inheritance or merger, the assignment takes effect without being registered, but the registration is made by providing notification of that assignment.

In terms of licensing patent rights, licences are granted merely by an agreement between the parties (non-registered licences) and licences granted upon registration at the JPO (registered as exclusive licences), in addition to an agreement between the parties. As for the former type of licence, there are no particular restrictions regarding formalities, such as the existence of a written agreement or notification to the JPO. However, the latter type of licence requires registration with the JPO to enter into force. It should be noted that if a registered exclusive licence is granted, other parties may not execute the scope of rights subject to that grant (even the patent right-holder).

As the grant of a registered exclusive licence requires registration at the JPO in order for it to come into force, it is necessary to make an application to the JPO setting forth the content of the licence agreed by both parties and to receive registration thereof. The granting of a non-registered licence comes into force merely by way of the execution of an agreement between the parties. Thus, generally, a licence of this kind is granted by preparing a licence agreement, as well as orally or even implicitly.