IP Guidance

Preface

A prior version of this guidance was cited as testimony by Mr. Edmund Chung during a U.S. Senate hearing on U.S.–Japan intellectual property rights in 1988. It was subsequently published in AIPPI Japan’s Overseas Journal in March and May 1991. Since then, patent law has continued to evolve in response to the need for stronger protection in line with technological advancements and global trends. Moreover, several landmark court decisions have significantly influenced patent practice. Accordingly, we have revised this guidance to incorporate these developments up to July 2025.

Yasunori Ohtsuka

Main Actors in Intellectual Property Fields

In Japan, the key IP bodies are the Japan Patent Office (JPO), the Intellectual Property High Court (IP High Court), and the Tokyo and Osaka District Courts. The JPO examines and grants patents, conducts invalidation trials via its Board of Appeal, and serves as an ISA for PCT applications. The IP High Court hears appeals from the JPO and the district courts. Japanese Customs enforces IP rights at the border. With the growth of Standard Essential Patents (SEPs), the Ministry of Economy, Trade and Industry (METI) and the Japan Fair Trade Commission (JFTC) have become influential in IP policy-making.

Filing routes for foreign applicants

PCT National Phase Entry

The procedure for entering the Japanese national phase from a PCT application is as follows:

Standard deadline: 30 months from the earliest priority date.
Late entry (from Apr. 1, 2023): Allowed if delay was unintentional.
Filing window for late entry:

• Within 2 months from the date it becomes possible to submit the translation.
• No later than 1 year from the missed 30-month deadline.

Requirement: Declaration stating delay was unintentional (no evidence needed).

Surcharge: JPY 212,100 per priority claim.

Translation

A Japanese translation must be submitted by the later of (a) 30 months from the earliest priority date, or (b) if the entry is made in the last 2 months of the 30 month period, 2 additional months after the entry date into Japan is automatically given without any additional fee.

Necessary information and documents

• A copy of PCT application (or its publication number)
• Copy of amendment of Article 19 and 34
• Power of Attorney

Points to check

• If you need to change the ownership of the applicant, please check if the assignment is recorded in checkbox PCT/IB/306. If it is not recorded, but you wish to change the applicant in Japan, the assignment must be recorded at the JPO.
• Please check the checkbox 304 if the Priority Documents are received by the World Intellectual Property Organization (WIPO), and send us the priority document if it is not recorded.
• Please check if a claim of a grace period is necessary. A claim for a grace period and supporting exhibits must be submitted within 30 days from the national processing date.

Paris Route

The procedure for entering the Japanese national phase from a PCT application is as follows:

Standard priority period: 12 months from the earliest priority date.

If missed: Priority right expires.

Restoration possible if:

Application filed within 2 months after priority period expires.

Delay was unintentional.

Requirements

Petition for restoration filed with the application.

Surcharge: JPY 212,100 per priority (Art. 43-2, Rule 27-2(4)).

Due date for filing translation

An application can be filed in Japanese or English, or any foreign language. If filed in a foreign language such as English, a Japanese translation must be submitted within 16 months from the priority date. Therefore, if an application is filed on the last date of the priority, the applicant is automatically given 4 months to file a translation.

Necessary information and documents

• Applicant name and address
• Inventor name and address
• Claims, Specification and drawings
• Priority date, number and country

Priority documents can be submitted through the WIPO DAS system. To do so, please provide the access code to use DAS.

• Power of Attorney

A patent application may be filed without a Power of Attorney (PoA). However, a PoA is required at certain later stages of prosecution, such as when filing a divisional application or lodging an appeal. To ensure a smooth and uninterrupted process, we request submission of a PoA at the outset of our representation.

A general power of attorney form may be submitted to the JPO in order to cover all future cases. For ongoing patent application procedures, the use of a general Power of Attorney allows for smoother and more efficient management.

No notarization or legalization is required for the Power of Attorney.

Patentability Requirements

Major requirements

Novelty (Article 29(1)(i)-(iii))

The Japanese Patent Act adopts the first-to-file system and requires absolute novelty. Accordingly, the patentable invention must neither be publicly known nor publicly used in Japan or anywhere in the world; the invention must not be described in any publications distributed in Japan or in any other country, including patent and non-patent publications; and the invention must not be on any website in Japan or in any other country prior to the time of filing. Here, the time of filing refers to the actual time of filing or the time of filing the priority application, if a priority claim is in effect.

Grace Period

Japanese patent law provides a 12-month grace period to protect applicants from the loss of novelty due to public disclosure of their invention. This grace period applies in the following cases:

(a) When the person entitled to obtain a patent discloses the invention through means such as sales, presentations to investors, or academic conferences.

Note: This does not apply if the disclosure was made through publication in a patent gazette (e.g., Japanese Patent Gazette, Utility Model Gazette, or Design Gazette).

(b) When the invention is disclosed against the will of the person entitled to obtain the patent, resulting in a loss of novelty.

Examples include unauthorized disclosure by a third party, malicious leaks by employees, or industrial espionage.

(c) To claim the grace period under (a), the applicant must secure a valid filing date in Japan within 12 months from the date of disclosure. The procedural requirements are as follows:

For Non-PCT Applications:

• A patent application must be filed in Japan within 12 months from the date of disclosure.
• A statement claiming the grace period must be submitted at the time of filing.
• Supporting evidence must be submitted within 30 days from the filing date.

For PCT Applications:

• An international application must be filed within 12 months from the date of disclosure to secure a valid filing date in Japan.
• The grace period claim and supporting evidence can be submitted at the time of the international filing.
• If not submitted during the international phase, the claim and evidence must be submitted within 30 days from the national processing date.

Claiming grace period for multiple disclosures

The Examination Guidelines allow the effect of the grace period claimed for the first publication to the later publication when the first and later publications are only closely related (for example, the relationship between broadcasting and re-broadcasting). If there is no such relationship between the publications, a grace period must be claimed for each individual publication. According to this practice, if there are multiple publications, a grace period must be claimed for each publication.

Inventive Step (Article 29(2))

An invention must have an inventive step over the prior art as of the patent filing date.

Since differences in technology cannot be measured quantitatively, issues such as whether or not the motivation for the invention existed in the prior art and whether or not the technical effects of the claimed invention are distinguishable over prior known technology are important in determining patentability.

In the inventive-step assessment, the Examiner must determine if the closest reference can be used as a base in combination with a second reference. If so, there must be some teaching or other motivation that would direct a skilled person to combine the references to achieve the claimed invention.

Under Japanese examination practice, a finding of such teaching or motivation, or other auxiliary factors that would have prompted the skilled person to combine a reference with the main reference to achieve the claimed invention, forms the foundation of the examination procedure.

When responding to an inventive-step rejection, emphasizing the invention’s unique advantages—based on the examined or appropriately amended claims and the specification—can be more compelling than simply denying the relevance of the cited prior art.

Enablement Requirement (Article 36(4)(i))

The specification must substantively describe the invention. Therefore, simply reciting the claimed invention in the specifications or describing mere desired outcomes does not satisfy the enablement requirement (Article 36(4)(i)). It is recommended to describe sufficient embodiments to support the claims. If the claims go beyond the embodiments, an enablement objection will be issued.

With respect to chemical or medical products, the manner of making and using the invention is often difficult to understand solely from their structures or names (see Examination Guidelines, Part II, Chapter 1, Section 1, Enablement Requirement 3.1(1)(iii)). Accordingly, disclosure of at least one embodiment is required.

Submission of additional examples after the filing date is generally not permitted. Therefore, the specification at the time of filing must disclose one or more representative examples sufficient to demonstrate enablement including experimental results.

Support Requirement (Article 36(6)(i))

In Japan, a patent is granted for the disclosed invention. The scope of the patent cannot go beyond the scope of what could have been predicted from the embodiments in the disclosure (Article 36(6)(i)).

The examiner assesses whether the technical concepts described in the embodiments can be reasonably generalized to the claimed invention by a person skilled in the art. If such generalization is deemed possible, the claimed invention is considered to meet the support requirement. Otherwise, the claim will be rejected for lack of support.

Clarity Requirement (Article 36(6)(ii))

If the technical relationship between the claim elements is not clearly defined, a clarity objection will be issued. This type of clarity objection is often accompanied by a prior art rejection.

Clarity objections are typically issued when certain terms or phases are included in patent claims. Examples of such terms or phrases include “about”, “approximately”, “preferably”, “desirably”, etc. For claims defined by numerical limitations or ranges, an upper and lower limitation should be defined. In such situations, if no upper or lower limitations are recited in a claim, a clarity objection may be issued.

Unity of Invention

Patent claim must satisfy the unity requirement. Unity of invention is assessed based on whether the group of claims shares a common novel technical feature over the prior art. If this condition is met, the claims may include multiple independent claims in the same category and also different categories of invention within a single application

Unity of invention is evaluated during substantive examination to determine the extent to which the claims should be examined together.

In Japan, the practice concerning unity of invention—which defines the scope of examination—is applied with a degree of flexibility for the benefit of both the examiner and the applicant. According to the Examination Guidelines, the scope of examination is determined as follows:

The examiner tries to find a novel special technical feature “STF” that is the technical feature distinguishable over the prior art starting from Claim 1 and going down the claims from there.

For example, if an STF is found in Claim 3, Claim 4 which depends therefrom will be examined.

The Examiner must examine Claims 5 and 6 if they have the same or corresponding STF(c) that is found in Claim 3.

For efficiency, the Examiner can examine Claims 7 and 8 even if they lack unity of invention in relation to Claim 3 at the Examiner’s discretion, if these claims share common technical significance (problem to be solved) or a common technical feature with the examined claims.

The Examiner may exclude Claim 9 from the examination if it does not share the above requirements in relation to the examined claims.

Typically, unity of invention objection is raised along with other issues, such as novelty issues. The response to a unity of invention objection may be addressed by amending the claims to include the common special technical feature. It may also be addressed by responding to the prior art rejection. Another option to address a unity of invention rejection is to cancel claims that are the subject of the unity of invention objection. Generally, the option of cancelling claims is the most common as the chance of success by traversing a unity of invention objection is relatively low under the Japanese patent practice.

Secret Prior Art Rejection

The Patent Law, Article 29-2 provides for secret prior art. If the claimed invention is anticipated by secret prior art, the application shall be rejected. Secret prior art comprises another person’s application whose filing/priority date is earlier than that of the present application and whose publication date is after the filing date of the present application.

However, this provision shall not apply in a situation where: the inventor(s) of the later invention are identical to the inventor(s) of the earlier invention; or the later applicant(s) is/are identical to the earlier applicant(s) at the application date of the later application.

A secret prior art rejection may be based on a single reference. To overcome such a rejection, it is sufficient to demonstrate a substantial difference between the claimed invention and the cited reference. Unlike an obviousness-type rejection, a secret prior art rejection does not require arguments addressing non-obviousness.

Examination system and acceleration of examination

Request for Examination

The request for examination must be filed within three years from the effective filing date of the application. In the case of a divisional application, whose effective filing date is deemed to be that of its parent application, if such parent filing date has elapsed more than three years prior to the filing of the divisional application, the request for examination for the divisional application must be filed within 30 days from the actual filing date of the divisional application.

A request for examination may be filed by any party, including a third party. When a third party files the request, the applicant is notified by the Japan Patent Office.

If the request for examination is not filed within the applicable period, the application is deemed to have been withdrawn.

As a general rule, patent applications are examined in the order in which examination requests are received. As of 2022, the average waiting time for the issuance of a first Office Action is approximately 10.1 months, although this may vary depending on the technical field of the invention.

If expedited examination is required, applicants may file a request for accelerated examination.

Expedited Examination

The Expedited Examination system implemented by the JPO is intended to facilitate the prompt examination of patent applications.

Applicants who have filed patent applications through the Paris route or the PCT route are eligible to request expedited examination.

To request expedited examination, the applicant must submit prior art references. These typically include citations from Office Actions issued in corresponding applications filed in the applicant’s home country or abroad, or references cited in international search reports during the PCT international phase.

The request must include a list of the prior art relevant to the claims, along with a statement regarding the patentability of the claims. A simple comment that “the claims are distinguishable from the cited references” is generally sufficient.

No official fee is required to file a request for expedited examination—the procedure is free of charge.

The Japan Patent Office (JPO) will review the request to determine whether the formal requirements have been met. If the request is accepted, an Office Action is typically issued within two to three months from the date of the request. The patent applicant is required to respond to this Office Action without any extension, and the examiner is expected to conduct a prompt examination of such a response.

Super Accelerated Examination

Super Accelerated Examination (SAE) is a special procedure designed to provide significantly faster examination. Under the SAE system, the Japan Patent Office (JPO) endeavors to issue the first Office Action within one month from the date of the request. In exchange, applicants are required to submit their response within two months, and no extension of the response period is permitted.

To be eligible for the SAE, the following two conditions must be met:

1. The invention must be in use or planned to be put into use within two (2) years from the filing date of the application.
2. The application must have been filed via the Paris route or the PCT route.

The examiner is requested to conduct a prompt examination of such a response within one month of its submission. If the applicant fails to respond in a timely manner, the benefit of the Super Accelerated Examination will be lost.

Patent Prosecution Highway (PPH) Program

The Patent Prosecution Highway (PPH) program serves as one of the accelerated examination procedures. If a foreign counterpart application filed in the United States, Europe, China, Korea, or a number of other contracting countries is issued as a patent, granted or indicated as to be granted, the applicant may request the PPH program relying on one of the granted patents in order to implement an accelerated examination of the patent application in Japan. The PPH program is also available for PCT applications.

With the PPH program, the Japanese claims must sufficiently correspond to the issued or allowed foreign counterpart claims. However, Japanese Examiners will conduct a search in the same manner as for ordinary applications. If prior art is discovered, the Examiner will issue an Office Action.

Necessary documentation to file a PPH request

The following information (documents) are required for PPH applications. Most of them can be omitted from the submission to the JPO, but non-patent literature must be submitted to the JPO.

Non-patent literature should be sent to us in PDF format.doc:

• Identification of the base patent application, country, and filing number (serial number)
• Copies of the Office Actions and responses (can be abbreviated, if available to the JPO through the DAS system)
• Copies of the granted claims (can be abbreviated if available to the JPO through the DAS system)
• Copies of the Notice of Allowance (can be abbreviated if available to the JPO through the DAS system)
• A list of the Cited References (can be abbreviated if available to the JPO through the DAS system)
• Copies of non-patent literature cited by the Examiner (in PDF format)

Appeal against Examiner’s Final Rejection

Appeal with or without amendment

A patent applicant may file an appeal with the Board of Appeal within four months from the date of the initial examination decision. The appeal may be accompanied by amendments or filed without amendments. Any amendments filed may be substantive, provided they fall within the permissible scope of amendment, and are intended to render the application patentable.

When an appeal with amendment is filed, the Examiner who issued the initial rejection conducts a review before the case proceeds to panel examination by the Board of Appeal. This pre-review stage is typically completed promptly.

If the Examiner determines pre-review stage that the amendment overcomes the previous rejection, the application will be allowed at this stage. If not, the Examiner will prepare an Examiner’s Pre-Review Report (EPR) and forward the case to the Board of Appeal (BOA) for full examination.

Upon issuance of the EPR, the applicant may submit arguments and proposed amendments for consideration by the Board of Appeal examiners, with the aim of prompting the issuance of a new Office Action to allow the amendments. The Board of Appeal will consider any persuasive arguments or patentable claim amendments. In such cases, a new Office Action may be issued to provide the applicant with an opportunity to formally submit the amendments before a final decision is made.

The examination by the Board of Appeal is usually performed by three trial Examiners. The examination is conducted in written form and there is no oral hearing. However, a request for an interview with the Board is possible.

Since the Board of Appeal conducts a de novo examination, claim amendments may be submitted together with the appeal.

Where the Board of Appeal determines that the Examiner’s rejection can be maintained in its present form, the rejection shall be upheld without the issuance of a new Office Action.

Where the Board of Appeal determines that the Examiner’s decision of rejection is not to be sustained and, upon its examination, finds no other grounds for refusal, it shall render a decision to grant the patent without issuing a further Office Action.

Where the Board of Appeal overturns the Examiner’s rejection or finds that the rejection was insufficiently reasoned, the Board shall proceed to examine the application for any further grounds for refusal. If new grounds for refusal are identified, the Board shall issue a new Office Action, which may include citations to additional prior art references. The applicant shall be afforded an opportunity to submit arguments and amendments in response, and the Board shall render its final decision upon consideration of the applicant’s response.

Nevertheless, the appeal process is subject to the following limitations, which should be carefully considered when deciding whether to pursue an appeal:

• No claim broadening – Substantive amendments are permitted; however, amendments must be limiting in nature and cannot broaden the scope of the claims.
• Restrictions on divisional filings – If the appealed application is allowed or rejected without the issuance of a new Office Action, the applicant cannot file a divisional application.
• No divisional after Board decision – If the Board of Appeal rejects the application, the only available remedy is to file an appeal with the IP High Court. Filing a divisional application is not permitted at this stage.

There are three options for responding to an Examiner’s rejection.

• Appeal to Board of Appeal with/without amendment within 4 months (not extendable) from the final rejection. A substantive amendment such as adding further limitations to claims is possible.
• Appeal to Board of Appeal with/without divisional application within 4 months from the final rejection.
• File a divisional application within 4 months from the final rejection to start a new prosecution, instead of filing an Appeal.

Outcome of Appeals

According to 2023 statistics, out of 21,047 appeals, 10,459 were allowed at the pre-review stage, and 5,942 were allowed by the Board of Appeal.

As a result, the overall allowance rate for appeals is relatively high at 81%.

Divisional Applications

Requirements for Divisional Applications?

A patent application that contains two or more inventions can be divided into one or more patent applications. The divisional application is entitled to claim the benefit of the parent application. The two major requirements for a valid divisional patent application are as follows:

New claims without introducing new matter

The claimed invention in a divisional application must be supported by the specification of the parent application. No new matter can be added. If new matter is added, the divisional application will not be regarded as a valid divisional application.

No double patenting issues

The divisional invention must not be substantially the same as the invention claimed in the parent patent. The claims of a divisional application be broader than the claims of the parent. If the claimed inventions of a divisional and its parent are regarded as mirror images of each other, they will be deemed identical and cause a double patenting issue. It is a requirement that there must be a non-obvious difference of at least one element between the original and divisional application.

Available period for filing divisional applications

• Any time before receipt of a first Office Action
• During the response term for the Office Action
• During the term for filing an Appeal against the Final Rejection by the Examiner (except for the Final Rejection by the Board of Appeal)
• Within 30 days from the Notice of Allowance (at the first round of examination stage, not at the Board of Appeal)
• The divisional application can be a basis for filing of a further divisional application

Effective Use of Divisional Applications

Re-filing the application

The scope of amendments permissible after the issuance of a Final Action or Final Rejection is narrowly circumscribed, often precluding applicants from making substantive changes necessary to overcome the grounds of refusal. To mitigate this limitation, the filing of a divisional application with a new claim may be considered as a form of re-filing, thereby enabling continued prosecution while preserving the applicant’s rights within the framework of procedural restrictions.

Further prosecution of rejected claims

If there are any unpatentable claims in the claim set, the application will be rejected. To secure prompt allowance of the allowable claims, while continuing prosecution of the rejected claims, a divisional application should be considered. Typically, the rejected claims are filed in the divisional application for further prosecution, while the allowable claim(s) remain in the original application which can then be promptly granted as a patent.

A fallback position

During the JPO Board of Appeal examination there is no guarantee of an opportunity to amend the claims. It may be strategically advantageous to prepare a divisional application to provide for greater freedom of prosecution to maximize flexibility in protecting a given invention.

Patent Term (duration) and Claim Construction

Patent term

Patent rights begin on the date the patent is registered and end on the date that is twenty years from the filing date.

The calculation of this 20-year term is not from the priority date, but from the application date in Japan. If the patent is derived from a PCT application, the 20-year term is calculated from the international filing date of the PCT application.

For a divisional application, the 20-year patent term is calculated from the earliest parent application date.

Patent term extension is available for certain pharmaceutical products, as discussed in the section entitled 'Patent Term Extension' within Section 'AAAA.'

Moreover, the patent term may be extended in circumstances where the delay is attributable to the patent examination process.

Territoriality Principal

A Japanese patent is enforceable only within Japan, in accordance with the principle of territoriality. Under this principle, no infringement arises if a claimed element is operated outside Japan.

This approach was revisited in the Comment Distribution System Case (IP High Court Grand Panel, May 26, 2023; Supreme Court, March 3, 2025). The case involved Japanese Patent No. 6526304, owned by DWANGO, claiming a system comprising a server and multiple receiving terminals. The server was located in the United States, raising the issue of whether transmitting a program from the U.S. server to Japan constituted “production” of the patented system under the territoriality principle.

The Tokyo District Court, applying the principle strictly, ruled on March 24, 2022, that there was no infringement. On appeal, however, the IP High Court ruled on July 20, 2023, that the invention was “worked” in Japan because the system’s operation and overall effects occurred domestically. The Supreme Court upheld this view, noting:

• The patented system is assembled through data processing when the service is provided;
• The effects of the invention are realized in Japan;
• The foreign location of the server is not essential; and
• The system’s use in Japan directly impacts the patentee’s interests.

Scope of Patent Claim

A patent confers upon the “patentee” the right to exclude others from working of the patented inventions for business use during the effective term of the patent.

The Patent Law defines the working of the invention according to the claim category.

A patent for an invention of an article is effective against making, using, transferring, exporting, importing, or offering for transfer of the article.

A patent for a method is effective against the act of using the method.
Since the act of use by an individual consumer (user) does not constitute patent infringement (because it is “not for business use”) under the Japanese Patent Act, method claims applicable to service providers are important.

A patent for a method of producing an article is effective against the act of producing the article and against the use, transfer, export, import, or offer for transfer of the article produced by the method.

A patent for a computer program is considered an invention of an article and is also effective for the act of providing the computer program through a communication line, in addition to the patent rights for the invention of an article.

Doctrine of Equivalents

The scope of the patent claim is constructed based on the claim description.

Claims are generally construed to have their ordinary and customary meaning as understood by a skilled person in the art.
The description of the patent specification and the prosecution history of the application are referred to in the claim construction. Claims defines the scope of patent claim, but there is infringement by the doctrine of equivalents（Ball Spline Case (Supreme Court Decision February 24, 1998).
In the ball spline case, the Supreme Court required five conditions for the infringement of doctrine of equivalents.

The first requirement is that the essential part of the invention must not be substituted.

The second requirement is that the substituted invention provide the same effect as the invention before the substitution. If the substitution of some of the elements of the invention no longer provides the original effect, then it is a different invention.

The third requirement that the person skilled in the art could have easily conceived of such a substitution at the time of infringement. This is to prohibit a person from trying to escape a patent right by substituting an element that became publicly known after the patent application was filed.

The fourth requirement is that the substituted invention is not equivalent to technology known at the time of filing. This is because it is not reasonable to extend the effect of the patent rights to technology that was publicly known at the time of filing.

The fifth requirement is that the patentee has not intentionally excluded the substituted invention from the claims in the patent examination stage (special circumstances).

March 24, 2017, the Supreme Court decision ruled in the Maxacalcitol case that the criterion for the fifth requirement is that "the mere failure to describe an obvious alternative in the patent specification does not constitute special circumstances. More specifically, the decision held that for there to be special circumstances as per the fifth requirement, the inventor would have had to be objectively aware of the alternative but nonetheless choose not to describe.

Contributory Infringement

In addition to literal infringement and doctrine of equivalents infringement, there is also contributory infringement. The act of helping patent infringement or providing essential components for patent infringement is considered to be a contributory infringement. Article 101 of the Patent Act specifies the requirements for contributory infringement.

Patent Term Extension?

Pharmaceuticals inventions

Some products such as a pharmaceutical product require administrative approval, and without such approval, the product cannot be sold. Thus, Article 67(2) of the Patent Act provides an extension of term of patent rights up to a duration of 5 years for cases in which there was a period of time during which a patent invention directed to a specific field, including a pharmaceutical patent invention, could not be practiced for reasons of safety tests and public approval.

Patents which are eligible for such extensions are related to agricultural chemicals, pharmaceuticals, pharmaceuticals for extracorporeal diagnostic use, products for regenerative medicine, and the like, and include substance, use, method of manufacture, and combination drug patents. Pharmaceuticals are not limited to those for human use and include pharmaceuticals for animal use. Patents for pharmaceutical intermediates, catalysts, and manufacturing apparatuses cannot be extended. Patents for medical devices cannot be extended as well.

Requirements and procedure for patent term extension

To obtain an extension, an application for a patent term extension must be filed within 3 months of the administrative approval of the product (Enforcement Order, Article 3). When it is anticipated to be impossible to obtain the administrative approval before 6 months prior to the patent expiration date, advanced procedures must also be completed (Article 67-6) by 6 months before the expiration date.

Patent term extension must be filed by the patentee (Article 67-7(iv)). Further, it is necessary that the patentee or an exclusive or non-exclusive licensees have obtained administrative approval of the product (Article 67-7(ii)).

The JPO will examine (1) whether the patent could or could not be practiced without approval, and (2) that the extended term is correct. The JPO may also examine other related issues.

The extendable term is the duration of time from the latest of the starting date of clinical trials, the date of application of approval, and the date of registration of the patent, to the date on which the certificate of approval is received. However, the extended term cannot exceed 5 years.

Scope of extended claims

The effect of extended patent rights is limited to the product which is subject of the approval (Article 68-2). For example, in a case where a patent is extended based on approval of a stomach cancer drug, the effect of the extended patent is limited to the usage of the drug for stomach cancer. On the other hand, in a case where a patent is extended based on approval for a particular dosage regimen, it is a case-by-case determination whether the extended patent covers other dosage regimens.

Patent Opposition

The patent opposition system is essentially a reexamination system for reviewing the validity of an issued patent by the Board of Appeal. The reexamination process begins when a third party files an opposition within 6 months of a patent being published.

Under the Patent Act, there are two routes for cancelling or invalidating a patent. The first is a patent opposition and the second is a patent invalidation trial. The opposition system is simpler and the opposition procedure is less complicated and quicker compared to a patent invalidation trial.

Grounds for Opposition

An opposition may be filed based on any of the following grounds.

An opposition may not be filed based on a violation of the rules for a joint application or derivation. For such grounds, the only way to challenge a patent is through an invalidation trial.

Opponent

Any person may file an opposition, regardless of whether they have an interest in the matter.

Oppositions are often filed in the name of a third party (“straw man”) to conceal the real party’s interest. The third party must be a genuine individual or legal entity capable of receiving correspondence from the Patent Office, not a fictitious name.

Opposition Procedure

The opposition period is 6 months from the patent publication date. This period is not extendable.

All grounds for the opposition and evidence must be submitted within the opposition period.

The official fee for filing the opposition is JPY 16,500 (US $157), plus JPY2,400 (US $23) per claim.

The JPO forwards a copy of the opposition brief to the patentee. However, the patentee cannot respond to the opposition brief at this time because the examination of the opposition has not yet started.

An opposition is initially examined by a panel of Board of Appeal Examiners. If the panel determines that any patent claim may be subject to cancellation, the JPO issues a Notice of Patent Cancellation and formally institutes the opposition proceedings. Upon receipt of the Notice, the patentee can respond to the notice with arguments and/or claim amendments, if necessary (First Review).

The response from the patentee is examined (Second Review) by the Examiners considering the opponent’s opinion. The opponent will have an opportunity to submit arguments. Limited new prior art may be introduced in the arguments.

If the patent is still found unpatentable upon second review, the JPO issues an Advanced Notice of Cancellation. The patentee may respond with arguments and amendments; this is generally the final opportunity to submit a response that includes amendments. The opposition will be rejected if the patent is maintained without institution of the opposition, or if the opposition is instituted, but the patent is determined to be valid in the proceeding.

If the opponent loses the opposition, the opponent cannot file any arguments or appeal against the decision. The only further measure available to the opponent is to file for an invalidation trial to the JPO.

Since the prohibition against double jeopardy does not apply to the decision of opposition, the prior art materials introduced in the opposition process can also be used in an invalidation trial.

If the patent is cancelled (in part or whole), the patentee can file an appeal to the IP High Court against the JPO seeking the overturn of the decision. Please note that the defendant in this cancellation litigation is the JPO, and not against the opponent.

Trials for Correction of Issued Patent Claims

Proceedings for amendment of issued Patent Claims

Post-grant amendments to claims, the specification, or drawings may only be made through a Trial for Correction, typically examined by a three-member Board of Appeal panel. Corrections may be filed at any time, except while an opposition or invalidation trial is pending; in such cases, amendments must be made within those proceedings. Amendments must narrow, not broaden, claim scope. For applications originally filed in English, claims may be amended to conform to the English text, provided no broadening occurs.

Requirements for a Patent Claim Amendment

A Trial for Correction may be filed to:

• Cancel claims.
• Restrict claims (must remain patentable).
• Correct errors (must remain patentable).
• Clarify unclear descriptions (must remain patentable).

It cannot be filed after service of an invalidation brief or opposition; in such cases, amendments must be made within those proceedings. A correction trial may be filed during infringement litigation if no invalidation trial is pending and can be used to counter invalidity arguments. No limit applies to the number of filings. Decisions are typically issued within about three months.

Patent Litigation

Patent Litigation Statistics in Japan

In Japan, patent litigation proceeds through trial sessions without a formal discovery process. The first stage addresses infringement and validity, typically through several preparatory proceedings (benron junbi tetsuzuki) and a technical session. If infringement is found, the second stage calculates damages. Many cases end in court-recommended settlements.

From 2014–2023, 69.4% of cases before the Tokyo and Osaka District Courts ended by judgment and 30.6% by settlement. Of judgments, 44% found no infringement and 21% found infringement. Of settlements, 24% favored patentees through cessation of infringement and/or payments. Overall, about half of patentee claims are upheld or partly recognized.

(Number of judgements and settlements at Tokyo and Osaka District Courts from 2014 to 2022, resource IP High Court)

Court systems for patent infringement cases

Patent litigation must start at the Tokyo or Osaka District Court which have exclusive jurisdiction over patent infringement cases. The Tokyo District Court has exclusive jurisdiction over cases in the Eastern portion of Japan, and the Osaka District court has exclusive jurisdiction over cases in the Western portion of Japan. The IP High Court located in Tokyo, which is a special branch of the Tokyo High Court, exclusively handles all patent cases from the Tokyo District Court and the Osaka District Court as well as any suit against appeal/trial made by the JPO.

The Tokyo District Court has four IP divisions and the Osaka District Court has two IP divisions. One bench consists of three judges in a main action. The IP High Court has four ordinary divisions and one Special Division (Grand Panel), the latter of which consists of five judges including four presiding judges of each of the divisions. The Supreme Court is the final court to hear appeals from the IP High Court. However, the Supreme Court has broad discretion as to whether to accept a petition for acceptance of final appeal from parties for discretional review (jokoku juri moshitate), unless there is a ground for mandatory review of appeal (jokoku), such as a violation of the Constitution.

Standing to sue in patent infringement actions

A patent holder or an exclusive licensee duly registered in the JPO patent register (Senyo Jisshikensha) have legal standings to bring a lawsuit seeking injunctive relief and damages. By contrast, an unregistered exclusive licensee (Dokusenteki Tsujo Jisshikensha) is limited to claiming compensation for its own damages.

Role of patent attorneys and attorneys at law

A party is free to have a legal representation in the Japanese civil procedures. In practice, however, it is common to have attorneys-at-law (Bengoshi) legally represent patent infringement cases. It is also common that patent attorneys (Benrishi) work together with attorneys-at law and these patent attorneys can co-represent patent infringement cases together with the said attorneys-at-law, provided that such patent attorneys have passed the Specific Infringement Lawsuit Counsel Examination.

Burden of proof

The burden of proving the cause of action as well as the damages suffered lies with the plaintiff. To prevail in a main action, the plaintiff must prove by a “high probability” standard that infringement of the plaintiff’s patent occurred, as opposed to a “preponderance of the evidence” standard that is used in other countries. However, there are some provisions in the Patent Act which help the plaintiff to meet the standard of proof, such as presumption of negligence of an infringer and presumption of the amount of damages incurred by the infringement (See Question 16.10).

Unlike the United States, there is no specific discovery process in Japan and the onus of producing evidence to the court will fall heavily on the plaintiff. However, the Patent Act provides that in patent infringement proceedings, the court, at the request of a party, may order the other party to produce documents that are needed to prove the infringement or to calculate the damages caused by the infringement. However, such an order may not be enforced if the person in possession of the documents has a legitimate reason for refusing to produce them.

Also, the Patent Act has recently introduced the concept of on-site inspection in which the court can appoint, upon the request of a party, a fair and neutral expert to enter the premises of the alleged infringer to examine documents, devices and the like under strict conditions (Article 105-2).

Complaint specificity in initiating infringement litigation

As no specific discovery process is available in the Japanese civil proceedings, the plaintiff needs to investigate and analyze the accused product or process and prepare well before commencing patent litigation. Based on the investigation and analysis, the plaintiff is required to describe in its complaint the identity of the accused product or process, and structures or features thereof. In addition, the plaintiff must provide a comparison between said structures or features and corresponding elements of each claim of the patent. Also, the plaintiff needs to describe in the complaint the approximate amount of damages he/she claims (which is used for calculation of stamp duties), the plaintiff can amend such amount in the subsequent proceedings.

Whether a cease-and-desist letter Is necessary prior to initiating litigation

A prior cease and desist letter is not a prerequisite for a patent holder to file a lawsuit seeking injunction and compensation for damages. However, it is quite common for a patent holder to first send such letter to the alleged infringer, inter alia, to explore the possibility to stopping the infringing activity and/or settle the case without filing a lawsuit. Please note that in Japan sending a cease and desist letter to retail stores could be treated as a patent holder’s misrepresentation to customers which is subject to an injunction and damage claim under the Unfair Competition Prevention Law.

Issues in the trial and how to proceed with the lawsuit (steps of trial at the court)

The court adopts a so-called “two-step” review of infringement cases. In the first stage, the court first reviews whether the defendant’s product or process infringes the plaintiff’s patent (infringement issues) and also addresses validity issues if the validity of the patent is contested by the defendant. When any validity issues are cleared and the court believes the patent to be infringed, the court will disclose its opinion to the parties. Thereafter, the proceedings then move to the second stage which involves damages calculations unless both parties agree to settle the case. Also, if the court determines that there is no infringement or that the patent is invalid in the first stage, the court ends the trial and will hand down its judgment in favour of the defendant unless both parties agree to settle the case.

In the Tokyo District Court’s practice, after the first oral hearing (to be held in court), the discussion is mainly conducted in preparatory hearing sessions (benron junbi tetsuzuki) held in judicial chambers in which the presiding judge and other judges analyze the issues involved until they are able to reach a conclusion regarding infringement.

Average duration of court proceedings

Patent litigation is initiated by the filing of a complaint and the production of documentary evidence by the Plaintiff. The court then serves the complaint on the defendant and sets the date for the first oral hearing and a due date for the answer to be submitted by the defendant.

The patent litigation process model published by the Tokyo District Court anticipates about five (5) rounds of preparatory proceedings (benron junbi tetsuzuki) to complete an infringement phase (the first stage) after the first oral hearing. During the preparatory proceedings, both parties exchange their briefs and produce their evidence. Explanatory sessions regarding technical matters will commonly be provided by both parties at the final phase of the first stage to have a better understanding of the technical issues.

At the fifth round of preparatory proceedings, according to the above model, the court discloses to the parties its opinion on the infringement. If the court determines that there is no infringement of patentee’s patent (or finds any grounds in favor of the defendant), the court ends the preparatory proceedings and closes the trial at the second oral hearing, or the Court can make a recommendation of settlement. In the case when the court determines that the defendant infringes the plaintiff’s patent and no recommendation for settlement is made, the court then proceeds to the second stage of calculation of damages. The model anticipates about three (3) more rounds of preparatory proceedings for the second stage.

It is common for a patent infringement case to take one year at the district court level and another several months if appealed to the IP High Court.

Expected progress of patent infringement proceedings in the model (the first stage)

Legal measures available to assist the plaintiff in proving its claims

There are several measures provided for in the Patent Act to help the plaintiff to prove its claims in patent litigation proceedings such as the following:

Presumption of negligence (Article 103)

An infringer of a patent right or exclusive license of another person is presumed negligent in the commission of the act of infringement.

Presumption of producing products by patented process (Article 104)

Where the invention of a process of producing a product has been patented and the product was not publicly known in Japan prior to the filing of the patent application, a product identical to such product shall be presumed to have been produced by the patented process.

Presumption of damages (Article 102)

The plaintiff bears the burden of proof of the actual damages incurred by the act of infringement of the defendant. However, considering the difficulty for the plaintiff to prove the amount of actual damages caused by the infringement, the Patent Act provides three types of presumptions where the amounts determined by way of the following are presumed to be the amount of damages: (i) “lost profits” calculated based on the infringer’s sales quantity with the patent holder’s profit rate; (ii) license fees that the patent holder would have obtained had the infringements not occurred; and (iii) profits made by the infringer (unjust enrichment).

The Patent Act was revised in 2019 (effective on April 1, 2020) as follows:

• The patent holder can seek “lost profits” within the limits of an amount proportionate to the production/sales capacity of the patent holder ('capacity').
• Since the IP High Court decision on September 25, 2006, the courts had not included the portion of “lost profits” beyond the patent holder’s capacity in the damages. The revision allows the patent holder to claim such a portion as being equivalent to license fees for the relevant license if given to the infringer (Article 102(1)(ii)).
• In the calculation of the damages according to licensing fees base, the court may consider the amount of license fees that would have been negotiated and agreed upon based on the presumption of infringement. License fees that presume infringement will be higher than those that are actually negotiated and agreed upon in practice (Article 102(4)).

In real business, license negotiations are undertaken with uncertainty regarding validity and infringement issues, and royalty rates are set at a win-win level.

However, in patent litigation, the damages session comes after the patent holder has cleared the infringement and validity sessions; therefore, a higher ex-post royalty rate should be applied. If ex-ante and ex-post royalty rate are the same rate, it encourages the infringer to think “it’s better to just pay small damages at the court rather than talk now”. With these changes, the court will apply higher a royalty rate than the ex-ante royalty rate. As of today, there have been two decisions ahead the enactment of the revision.

• IP High Court decision on June 7, 2019 (H30(ne)10063)
  - ruled that the royalty rate in a litigation setting must be higher than a normal royalty rate, and applied a 10% royalty to the infringer’s profits (marginal profit: deducting direct costs for manufacturing and selling the infringing products from the sales)
• Osaka District Court decision on June 20, 2019 (H29 (wa) 9201)
  - ruled that the royalty rate in a litigation setting must be higher than the normal royalty and applied 7% rate to the amount of sales.

Expert opinion for calculation of damages (Article 105-2-12)

Where, upon the request of a party, the court orders that an expert opinion be obtained for the calculation of damages arising from the act of infringement, the other party shall explain to the expert witness the matters necessary for the expert witness's opinion.

Determination of reasonable amount of damage (Article 105-3)

Where the court has determined that there are damages to be awarded and it is extremely difficult, due to the nature of the circumstances, to prove the facts necessary to determine the amount of damages, the court may determine a reasonable amount of damages based on oral arguments and the result of the examination of evidence.

Legal measures available to the defendant

In patent infringement proceedings, the defendant submits the answer to the complaint before the first oral hearing and briefs any number of times during the subsequent proceedings. The defendant commonly provides (i) a non-infringement defense and (ii) an invalidity defense.

A non-infringement defense is that the accused product or process does not fall within the technical scope of the patented invention. An invalidity defense covers almost all reasons for patent invalidity including novelty, non-obviousness (inventive step) and clarity issues. The invalidity defense will not, however, actually invalidate the patent in this proceeding as invalidity is determined in an invalidation trial before the JPO. If an invalidity defense is successfully allowed by the court, the plaintiff cannot enforce the patent right against the defendant of the case.

Also, the defendant can simultaneously initiate a patent invalidation trial before the JPO.

Further, the defendant may claim that he/she has been practicing the invention covered by the patent prior to the grant of such patent, without knowledge of the patent (“prior use”), or that he/she used the invention for the purpose of experiment or research. Parallel import or a gray market defense could also be argued under certain conditions.

As a general rule for tortious acts, the right to claim compensation for damages incurred by the act of patent infringement lapses by prescription if it is not exercised within three years from the time when the patent holder comes to know of the damages and the identity of the alleged infringer, or within 20 years from the act of infringement.

Denial of infringement by defendant

In patent infringement proceedings, when the defendant (alleged infringer) wishes to deny an allegation about the accused product or process, the defendant is required to actively rebut the allegation by clarifying the alleged act of infringement. If there are reasonable grounds that prevent the defendant from making such a clarification, however, he/she is not required to do so.

This is not a shifting of the burden of proof and the purpose is to expedite the proceedings. For example, if the plaintiff identifies that the accused process that the defendant employs as “A-B-C-D” and if the defendant wishes to deny this allegation, he/she needs to clarify that his/her process is actually “A-B-C-E”, for example.

Filing an invalidation trial with the JPO

In addition to non-infringement arguments and invalidity arguments in the court proceedings, it is very often that the defendant files a request for a trial for patent invalidation with the JPO Board of Appeal.

Under the Japanese law, the JPO is the only authority that can invalidate the issued patent. However, the court has a power to review the validity issues of the accused patent when the validity question is raised in the proceeding. If the defendant proved the invalidity of the patent, the court could deny the infringement and damage claim.

When a request for a trial for patent invalidation is filed, the JPO will proceed with the trial promptly, keeping in mind that the relevant patent infringement case proceeds in parallel.

Advantages for requesting a trial for invalidation is that the validity of the patent is examined by the eyes of technical experts and is managed by the Board of Appeal Examiners to focus on the issues raised by the petitioner or by the Examiners.

Effect of invalidation trial on court proceedings

The court may, if it considers it necessary, stay the court proceedings until the trial decision before the JPO becomes final and binding. In practice, however, the court rarely stays its patent infringement proceedings.

As the IP High Court exclusively handles all patent cases from the Tokyo and Osaka District Courts and all litigations for rescinding a trial decision by the JPO, even when decisions of the court and the JPO are not consistent, it is expected that the same bench of the IP High Court will review both relevant cases together in practice, and where feasible, render consistent decisions.

Declaratory judgment of non-infringement

An alleged infringer can seek from the court a declaratory judgment of non-infringement. To be precise, the alleged infringer files a motion in the court to confirm that the patent holder concerned (the defendant) does not have the right to seek a permanent injunction and/or compensation for damages against the alleged infringer (the plaintiff). The alleged infringer needs to show the fact establishing the benefit of seeking confirmation, i.e., the existence of an actual dispute. In this regard, a cease and desist letter from a patent holder indicating that the recipient (the alleged infringer) is infringing the patent normally satisfies this requirement.

Role of expert opinions in infringement litigation

In patent infringement proceedings, both parties commonly submit to the court expert opinions and present their arguments in their briefs relying on such expert opinions. Also, the court can designate an independent expert if it considers it necessary. However, it is not common for the court to allow witness testimony including expert witness testimony.

Expert opinion for calculation of damages can be available in the damage proving stage and the court designates, upon the request of a party, a fair expert such as a public certified accountant to calculate the amount of damages (Article 105-2-11).

The Patent Act has recently introduced on-site inspection in which the court may appoint, upon the request of a party, a fair and neutral expert to enter the premises of the alleged infringer to examine documents, device and the like under strict conditions (Article 105-2).

Settlement

Parties to a patent dispute are free to settle out-of-court or in the court proceedings at any time. In practice, the court often recommends a settlement (judicial settlement) in patent infringement proceedings. Depending on cases and parties thereto, the court sometimes makes a recommendation of settlement at an early stage but typically does so when it discloses its opinion on the infringement after it reaches the conclusion, and after the second stage (damage proving stage) is concluded.

The judicial settlement can cover not only the patent dispute before the court but also any other relevant issues between the parties; for instance, other patents which are not subject to the current litigation, and other patent litigations pending outside Japan. Also, a judicial settlement can cover any business arrangements between the parties which are not necessarily regulated by the Patent Act.

When a settlement, a waiver, or an acknowledgement of a claim is entered in the judicial record of settlement, that entry has the same effect as a final and binding judgment.

Bearing of Court Costs and Attorneys’ Fees at the End of Litigation

The court orders the losing party to bear court costs such as stamp duties. Unlike the United States, the court will not order the losing party to bear “all attorneys’ fees” incurred by the prevailing party. However, the court normally orders the losing party to bear approximately 10% of the damages awarded by the court to be deemed as attorneys’ fees incurred by the prevailing party.

May the Defendant Seek Restitution After Paying Damages to the Plaintiff.

When the court’s judgment of patent infringement in favor of the plaintiff becomes final and conclusive and thereafter the JPO determines that the patent concerned is to be revoked or invalidated and such a decision becomes final and binding, the defendant cannot claim in subsequent retrial proceedings that that patent is revoked or invalidated. Thus, the plaintiff is not required in the retrial proceedings to return the compensation it received. This restriction will also apply to a case when the JPO subsequently determines that the registration of the patent term extension must be invalidated.

On the other hand, if the prior final and conclusive judgement is an injunction and the JPO’s subsequent determination is to invalidate the patent concerned, the injunction is to be lifted, and the defendant can work the invention accordingly.

Available dispute resolution mechanisms other than litigation

Parties can choose any out-of-court means to solve patent disputes (Alternative Dispute Resolutions or “ADR”) if they so agree.

Arbitration is a typical ADR and an arbitration award has the same effect as a final and conclusive judgement under the Arbitration Act. Though arbitration can be used on an ad-hoc basis, there are several certified institutions which provide ADR services, such as the Japan Intellectual Property Arbitration Center (JIPAC) and the Japan Commercial Arbitration Association (JCAA). In September 2018, the International Arbitration Center in Tokyo (IACT) was established. These institutions also provide mediation services.

Please note that judicial mediation (chotei) is also available before the Court. In 2019, the court started its new operation of judicial mediation regarding intellectual property (“IP mediation”) which is available in the Tokyo District Court and the Osaka District Court, provided that both parties submit their agreement on jurisdiction. A mediation committee consisting of IP court judges, attorneys-at-law and patent attorneys etc. hears a dispute and reviews arguments and relevant materials. Then the committee provides its opinion and, where appropriate, its mediation proposal to the parties. It is expected that the committee will provide its opinion and mediation proposal before or at the third meeting. When an agreement is reached between the parties during the proceedings and it is entered in a judicial record, such an entry has the same effect as a judicial settlement.

Inspection and copying of other parties’ patent litigation records

While the court does not publish a case record of a pending case online, such case record can be publicly available at the relevant court. Any person may file a request to inspect a case record with the court clerk of the relevant court where a particular case is pending, by identifying the case number. With regard to a case record involving oral arguments that are prohibited from being disclosed to the public pursuant to the Constitution and the Court Act, only a party to the case and an interested party can request to inspect such relevant portion of the case records.

On the other hand, only an interested party to the case can copy the case records.

The court may also rule, upon the request of a party in the case, to limit the persons that may request to inspect or copy part of said case record in which the relevant confidential information is entered or recorded to the parties to the case.

Please note that a preliminary disposition case is not open to the public and only parties to the case and an interested party can inspect and copy such case records.

An interested party in connection with a preliminary disposition is a third party whose rights or legal benefits under public law or private law are directly or indirectly affected by the case concerned, and a third party whose factual or economic benefits are affected is not an interested party. A company that has concern about a stable supply of parts of another company which are subject to a preliminary disposition is not treated as an interested party and thus cannot inspect and copy the case record of the preliminary disposition.