Responding to a trademark infringement warning letter in Japan

What a company should first check after receiving a trademark infringement warning letter

• The warning letter and deadlines: The company checks the warning letter and attachments, the date of receipt, the action requested by the other party, and the response deadline, and organizes this information together with the original documents.
• Registration information: The company organizes the registration number, rights holder, and sign identified in the warning letter and retains the attached registration documents.
• Where the sign appears: The company identifies the goods or services, packaging, websites, stores, and business partners' published materials on which the sign appears.
• Records before changes: The company saves dated photographs and screenshots showing the sign's position and size and the surrounding text before making changes.
• History of use: The company organizes the date on which use began and the subsequent history, and collects documents showing the sales areas, advertising, and transactions at the relevant times.
• Contracts and sourcing: The company identifies its suppliers and the goods' distribution channels and checks sales agreements, license agreements, and other documents evidencing permission.
• Stock and sales records: The company organizes records of stock, orders, and shipments of the relevant goods, together with sales quantities, revenue, and costs for each period.
• Other notices: The company separately checks the subject matter, procedures, and deadlines of notices received from business partners, online marketplaces, Japan Customs, or others.

We compare the documents provided by the company with information about the rights and assist with reviewing whether infringement has occurred and considering a response strategy.

The approach to response deadlines in warning letters and general matters to consider when preparing a response are explained in Responding to IP infringement warning letters.

1 Checking registration and use to assess trademark infringement

The registered trademark, rights holder, and basis of the warning

The company uses the warning letter and attachments to organize information about the sign, goods or services, and claims in question.

We check whether a registration exists, the rights holder, the registered trademark, the designated goods or services, the application date, and the status of the right both at the time of use and now.

A warning letter may also include claims under the Unfair Competition Prevention Act concerning widely recognized product names, store names, or other signs. Because a claim may succeed even without a trademark registration, we separately consider how widely the sign is recognized and, depending on the basis of the claim, whether there is confusion or other relevant circumstances.

Similarity of trademarks and goods or services

The company organizes information about the sign it uses and the nature, purposes, and purchasers or recipients of its goods or services.

We consider similarity by reviewing the overall impression conveyed by the appearance, sound, and meaning of the trademarks, taking actual trading conditions into account. For goods or services, we check their purposes, who manufactures or provides them, the channels through which they are sold or provided, and the relevant purchasers or users. We then consider whether the use of identical or similar trademarks may cause them to be perceived as coming from the same business. Whether the class numbers are the same or different does not, by itself, determine similarity.

How the sign is used and the goods' distribution channels

The company prepares materials showing the sign's position and size and the surrounding text and images, together with records of sourcing and distribution channels.

We consider whether the sign is used to indicate the source of goods or services from the perspective of purchasers or users. If it is not used in this way, the trademark right may not extend to that use. If the sign appears in descriptive text, we check the context and how it is actually displayed. Even when the company's own brand appears alongside it, the disputed sign may function as a separate indication of source.

Even where the sign is used to indicate source, we separately consider limitations on the effect of a trademark right concerning indications of names, quality, and similar matters. A trademark right may not extend to the display of the company's own name or a well-known abbreviation of it in an ordinarily used manner. Where a company name is displayed without a corporate designation such as "Kabushiki Kaisha" (stock company), whether the abbreviated name is well-known may become an issue. For a store name, we also check its relationship to the business and how it is displayed, and consider individually whether it is treated as the company's own name. However, if the company uses its own name or similar indication for the purpose of unfair competition after the other party's trademark right has been registered, this limitation concerning names and similar indications is unavailable.

A trademark right may also not extend to indications of the common name, quality, raw materials, purposes, or similar characteristics of goods or services displayed in an ordinarily used manner. We check not only whether the expression appears in a dictionary, but also whether it describes the common name or characteristics of the goods or services and how it is actually displayed.

The resale or parallel importation of genuine goods may not constitute infringement of a trademark right. However, even if the contents are genuine, possessing goods for sale in packaging bearing a registered trademark affixed without proper authority may be deemed infringement of a trademark right. We check the nature of any processing or repackaging and the signs appearing on the goods, packaging, and advertising separately.

For parallel imports, we check whether the trademark was lawfully affixed by the foreign trademark owner or a person licensed by that owner, and whether the Japanese and foreign rights holders are the same person or have a relationship that allows them to be regarded as legally or economically the same person. We also consider whether there is no substantial difference from authorized goods in Japan in the quality guaranteed by the trademark, taking into account matters such as whether the Japanese trademark owner is in a position to control quality directly or indirectly.

2 Considering prior use, cancellation for nonuse, and invalidation of a registration

A right to use a trademark based on prior use, cancellation for nonuse, and invalidation of a registration involve different dates for assessment and different legal effects. We consider future use separately from monetary claims relating to past use.

Conditions for continuing to use a sign used earlier

The company organizes records showing when use began, sales and advertising at that time, and subsequent use.

We consider whether the company used the sign in Japan without a purpose of unfair competition before the other party filed its application; whether, as a result, the sign was widely recognized among relevant purchasers or users as identifying the company's goods or services at the application date; and whether the company has continued using the sign for those goods or services. If the conditions are met, the company may be entitled to continue use based on prior use, but starting use earlier is not enough. We check the regions and groups of purchasers or users among whom the sign was known, and the extent of that recognition, in light of actual trading conditions at the time. Even if a right based on prior use is recognized, the trademark owner or another entitled party may require the company to add an appropriate indication to prevent confusion.

Considering cancellation of an unused registered trademark

The company records the other party's sales and advertising activities, together with the dates on which they were checked.

We investigate whether the rights holder or a person licensed to use the trademark has failed to use the registered trademark, including a trademark regarded as identical under generally accepted standards, in Japan for the relevant designated goods or services for a continuous period of 3 years or more. We then consider a request for cancellation of a registration for nonuse before the Japan Patent Office (JPO). The other party bears the burden of proving use, but the registration is not canceled where, for example, there is a justifiable reason for nonuse. Filing a request does not, by itself, entitle the company to continue use.

When a cancellation decision becomes final and binding, the right in question is deemed to have ceased to exist on the date on which the request was registered. This does not automatically resolve monetary claims relating to use before that date.

Grounds for asserting invalidity and time limits

The company organizes the documents it holds relating to the application and registration.

We check the grounds for invalidation, the date as of which they are assessed, and whether the 5-year time limit from registration of the trademark right applies, including any exceptions. When an invalidation decision becomes final and binding, as a general rule, the right is deemed never to have existed, but different treatment applies where invalidation is based on grounds arising after registration.

In infringement litigation, enforcement may also be contested on the ground that the registration should be invalidated in invalidation proceedings before the JPO. However, this defense may be restricted depending on the grounds for invalidation, the time elapsed, and whether a request for invalidation was filed within the applicable period. Even where an invalidity defense is restricted, we consider individually whether other defenses are available. A restriction on enforcement in litigation does not itself remove the registration.

3 Deciding the extent of continued use, changes, or discontinuation

Sales and advertising while the matter is under review

We check whether infringement has occurred and the legal basis for continuing use, and consider whether changes or discontinuation are necessary. If infringing sales continue, sales during that period may also be subject to damages claims. Criminal penalties are also prescribed for intentional infringement of a trademark right. Receiving a warning does not, by itself, establish infringement. We check the contents of the warning, the facts known to the company, and its subsequent response, and consider intent individually.

The company organizes information about stock and orders for the relevant goods, its advertising, and the time needed to make changes. In light of our review, the company decides the extent to which sales and advertising are to continue, change, or stop, and which facts, if established, would lead it to reconsider its approach.

Reviewing proposed changes to names and signs

The company prepares proposed replacement names and logos and drafts showing how they would appear on packaging and web pages.

We consider the proposals in relation to the other party's rights, taking into account their sound, meaning, appearance, and manner of use. Changing only some letters or the typeface does not necessarily avoid infringement. We also check the goods or services for which the proposed signs would be used and their position and size.

The company identifies the time needed for the transition and its effects on transactions, and decides which proposal to adopt. The company also identifies the period during which the old and new signs would coexist and the goods concerned, and we consider whether negotiations are needed concerning use during that period. Because a name change does not resolve claims relating to past use, we consider future use separately from settlement of past claims.

Handling signs on stock, websites, and business partners' materials

The company records signs before changes are made, for example by saving photographs and screenshots, and retains these records together with sales documents. It also identifies where the signs appear. Even if sales stop, possessing goods bearing a registered trademark or a similar mark for sale may be deemed infringement.

Where infringement is established, the rights holder may seek an injunction together with measures necessary to prevent infringement, such as disposal of the relevant goods. We consider the necessity and scope of the measures, including whether removing or replacing the signs would be sufficient.

Checklist when considering changes or discontinuation

Area	Signs to check	Materials the company checks	Matters we consider
Products and packaging	Markings on the products, tags, packaging, and enclosed materials	Actual items and photographs, stock lists, and shipment records	Whether relabeling or similar measures can address the issue, how stock is handled, and the scope of any agreement
Company website and online sales	Product names, images, advertising, and URLs	Lists of URLs, saved screenshots, and authority to update content	What needs to be changed and whether applications to online marketplaces or others are necessary
Stores and business partners	Signs, menus, and business partners' published materials	Photographs, lists of distribution recipients, and contract and delivery records	The scope of changes to request and the explanations to provide to business partners

When making changes, the company proceeds in light of our review and also checks the outcome of requests to change signs managed by third parties.

4 Addressing monetary claims and responding to business partners and online marketplaces

The period covered by a damages claim and the basis of calculation

The company organizes records of sales quantities, revenue, and costs for each period and each category of goods or services covered by the claim.

We compare these records with the duration of the right and the history of use, and consider liability and the basis of calculation. Sales before receipt of the warning may also be subject to damages claims. Because negligence is presumed in damages claims for infringement of a trademark right, lack of knowledge of the registration alone does not necessarily relieve the company of liability.

Examples of calculation methods include presuming that the profits obtained through infringement are the amount of damages, and claiming an amount equivalent to a license fee. We distinguish revenue from profit and also consider circumstances that may rebut the presumption and the basis for the license fee. In determining an amount equivalent to a license fee, the court may also consider the fee that would have been agreed between the parties on the premise that infringement had occurred. Rates used in ordinary contracts do not necessarily apply without adjustment.

Settlement of past claims and conditions for future use

The company identifies its preferred terms for resolution, such as changing the sign, discontinuing use, or continuing use under a license.

We negotiate while distinguishing the period and scope of claims to be settled from the signs, goods, sales channels, and periods permitted for future use. We separately check what the payment covers and the conditions to be agreed for future use.

Issues concerning breach, termination, or expiry of an existing license agreement are covered in Disputes over intellectual property licenses.

Explanations and procedures involving business partners and online marketplaces

The company checks notices sent to business partners, takedown notices from online marketplaces, terms of use, and response deadlines. We consider the explanations to provide and the materials to submit. In addition to the terms of any agreement with the rights holder, we check the marketplace's procedures and decisions needed to reinstate the listing.

If the company receives a notice from Japan Customs concerning identification procedures to determine whether goods infringe intellectual property rights, it checks the type of notice and the deadline, and we consider filing a statement contesting infringement and submitting evidence and opinions.

Key legislation and official sources

English translations of legislation are provided for reference. The Japanese texts are authoritative.

Article topic	Legislation or official source	Source type and English version reviewed
Registration, designated goods or services, and the scope of trademark rights	Trademark Act — Japanese text: e-Gov; English text: Japanese Law Translation	The linked sources are Japanese legislation and an English translation (earlier version). The English translation identifies its amendment version as Act No. 51 of 2023.
Claims concerning unregistered product names, store names, and other signs	Unfair Competition Prevention Act — Japanese text: e-Gov; English text: Japanese Law Translation	The linked sources are Japanese legislation and an English translation (earlier version). The English translation identifies its amendment version as Act No. 51 of 2023.
Similarity of trademarks and goods or services	Japan Patent Office, Examination Guidelines for Trademarks	Administrative examination guidelines. English version published by the Japan Patent Office (guidelines effective April 1, 2026).
Use as an indication of source; names, abbreviations, and descriptive indications	Trademark Act — Japanese text: e-Gov	Legislation. English translation as in the first row.
Parallel imports of genuine goods	Supreme Court, First Petty Bench, judgment of February 27, 2003, 2002 (Ju) No. 1100 — Japanese judgment	Court judgment. Japanese original; no English translation relied on.
A right to use a trademark based on prior use and indications to prevent confusion	Trademark Act — Japanese text: e-Gov	Legislation. English translation as in the first row.
Cancellation for nonuse, proof of use, and the effective date of cancellation	Trademark Act — Japanese text: e-Gov	Legislation. English translation as in the first row.
Grounds for invalidation, time limits, and the effect of invalidation	Trademark Act — Japanese text: e-Gov	Legislation. English translation as in the first row.
Invalidity defenses in infringement litigation and the presumption of negligence	Trademark Act; Patent Act, as applied to trademark rights under the Trademark Act — Japanese text: e-Gov; English text: Japanese Law Translation	The linked sources are Japanese legislation and an English translation (earlier version) of the Patent Act. The English translation identifies its amendment version as Act No. 48 of 2024. For the Trademark Act, see the first row.
Restrictions on invalidity defenses after expiry of the applicable period and consideration of other defenses	Supreme Court, Third Petty Bench, judgment of February 28, 2017, 2015 (Ju) No. 1876 — Japanese judgment	Court judgment. Japanese original; no English translation relied on.
Injunctions, possession of goods for sale, disposal, and criminal penalties	Trademark Act — Japanese text: e-Gov	Legislation. English translation as in the first row.
Damages based on profits or an amount equivalent to a license fee	Trademark Act — Japanese text: e-Gov	Legislation. English translation as in the first row.
Japan Customs identification procedures	Customs Act — Japanese text: e-Gov; English text: Japanese Law Translation	The linked sources are Japanese legislation and an English translation (earlier version). The English translation identifies its amendment version as Act No. 16 of 2018.
Notices, statements contesting infringement, and submission of evidence and opinions to Japan Customs	Japan Customs, Flow of identification procedures — Official procedural information in Japanese	Administrative procedural information. Japanese source; not a legislative translation.

The English translations linked above are earlier versions and do not reflect all amendments in force on the review date.

Legal information reviewed: September 27, 2026

Frequently asked questions

How we assist with responses to trademark infringement warnings

Responding to a trademark infringement warning requires checking the legal basis for each sign and each category of goods or services, and making separate decisions about future use and claims relating to past use. We offer consultations on individual matters concerning whether infringement has occurred and whether the rights are valid; the extent of continued use, changes, or discontinuation; responses and negotiations with the rights holder and review of agreement terms; and procedures involving business partners, online marketplaces, and Japan Customs.

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This article is provided for general informational purposes only and does not constitute legal advice on any specific matter. Please consult us regarding your specific situation. The content is based on the laws and regulations in effect as of the date of the last update.