How Letters of Consent Rules Diverge in Japan and South Korea

Japan and South Korea both introduced letters of consent (LOCs) into trademark law in 2024. This marked a significant development in both jurisdictions’ intellectual property (IP) systems. While the underlying principles of allowing LOCs to facilitate the coexistence of similar trademarks are similar, the specific legal provisions, procedural guidelines, and the implementation of LOCs in Japan and South Korea reveal notable differences.

This article explores these contrasts by examining key elements of LOC regulations, from the legal foundations and submission processes to requirements, limitations, and the broader implications of trademark coexistence.

Legal Provisions and Implementation Timelines

Japan’s LOC provisions came into effect on April 1, 2024, under Article 4(4) of the Japanese Trademark Act, while South Korea’s similar provisions were introduced a month later, on May 1, 2024, under Articles 34(1)7 and 35(6) of the Korean Trademark Act. Both countries established clear legal grounds for LOCs within their trademark laws, enabling the coexistence of trademarks in cases where senior trademark owners consent to the registration of a junior mark.

However, a major difference between South Korea and Japan’s consent systems lies in their respective applicability to pending trademark applications. South Korea’s consent system extends to trademarks already under examination at the time of its implementation (May 1, 2024), whereas Japan’s system applies only to applications filed after April 1, 2024. As a result, the following distinctions have emerged.

Current Status of Examination of Trademarks Relating to LOCs

In Japan, LOCs remain largely unexamined as of late 2024. The examination process for applications involving LOCs is set to commence in early 2025, with no current cases where consent has led to an approved registration. This reflects Japan’s cautious and gradual approach to integrating LOCs into trademark examination, leaving future developments to determine how LOCs will influence trademark approval outcomes.

Conversely, South Korea has already incorporated LOCs into its trademark examination process. Following the May 2024 enactment allowing LOCs, the Korean Intellectual Property Office (KIPO) reported that, by August 31, 2024, it had received 447 LOCs. Of these, it granted 34 registrations, published 185 for opposition, and 217 remain under examination. In six cases, LOCs were filed during appeal proceedings against refusal decisions. This process for LOC approval demonstrates a proactive approach by South Korea, where applicants receive immediate feedback on LOC outcomes.

Japan’s methodical approach contrasts sharply with South Korea’s rapid adoption and application of LOCs, highlighting distinct strategies in the two systems for integrating third-party consent in trademark registration.

Examination Guidelines and Manuals

Both Japan and South Korea have published guidance on the examination of LOC submissions, but their approach to accessibility and language differs. Japan has published updated Examination Guidelines for Trademarks and the Trademark Examination Manual (both in English) covering LOC-related provisions, which are readily accessible to international practitioners. These are outlined in Chapter 19 of the Guidelines and relevant sections of the Manual (42.400.01 and 42.400.02).

In contrast, South Korea has published a leaflet on LOCs and a sample LOC form on the KIPO website, but these documents are only available in Korean, making them less accessible to non-Korean-speaking stakeholders.

LOC Submission Process and Timing

Both jurisdictions allow the submission of LOCs during the trademark application process. In Japan, an applicant can submit an LOC at any point during the trademark examination or appeal stage, offering applicants considerable flexibility. Typically, applicants submit LOC-related documents in response to a Notice of Reasons for Refusal when the examiner determines that the junior mark is similar to a senior registered mark.

However, applicants aware of a conflicting senior mark may also submit the necessary documents at the time of filing their application or at any stage before receiving the notice. This provides flexibility in addressing potential conflicts early in the process.

In South Korea, an applicant can submit an LOC when filing a trademark application or amending goods or services, as outlined in Articles 40 and 41 of the Korean Trademark Act. Amendments are permitted in various situations, including the following:

• Responding to a KIPO office action citing a conflicting senior mark;
• Before publication;
• During the three-month reexamination period after a refusal; or
• Within 30 days after filing an appeal against KIPO’s refusal.

This system provides applicants multiple opportunities to submit an LOC at different stages of examination and appeal.

Requirements for LOC Submission 

Japan and South Korea have distinct requirements for LOC submissions. In Japan, the LOC must include detailed information about the senior and junior trademarks, including their registration/application numbers, designated goods/services, and a statement of consent (see Manual 42.400.02, 1.(1) and (2)). Furthermore, it must be accompanied by documentation proving no likelihood of confusion between the marks, taking into account factors such as the following:

• The similarity of marks;
• Their well-known status; and
• Consumer overlap (see Guidelines Chapter 19: 4(3), Manual 42.400.02, 2).

In contrast, South Korea’s requirements are less elaborate, focusing primarily on basic details of the trademarks and a simple statement of consent, without the extensive evidentiary requirements that Japan imposes. The KIPO examiner is not required to assess the likelihood of confusion when two marks coexist. Unless the marks and their goods are identical, the examiner must withdraw the citation if the owner of the cited mark has submitted an LOC. Consequently, South Korea does not impose strict requirements for LOC submission.

LOC Forms and Format

Both Japan and South Korea provide sample LOC forms. Japan offers a sample in its Trademark Examination Manual (see Manual 42.400.02), while South Korea provides a sample form on the KIPO website. However, neither jurisdiction mandates the use of these forms, allowing parties to submit their own versions, as long as they comply with the guidelines or manuals.

Examiner Discretion and Registration Outcome

One of the more significant differences between the two systems is the examiner’s discretion. In Japan, even if an LOC and LOC-related documents are submitted, the examiner retains the right to refuse the application if he/she believes that there is still a likelihood of confusion. The examiner typically requests additional materials before issuing a final rejection.

In South Korea, however, KIPO must remove its citation of the senior mark and proceed with registration upon receiving an LOC, provided no other grounds for refusal exist.

Legal Formalities

The two jurisdictions diverge on the requirements for signatures, seals, and notarization of LOCs. Japan does NOT require signatures, seals, or notarization for LOCs, and copies of documents are sufficient unless there are concerns about their authenticity.

South Korea, on the other hand, requires a signature or seal by the parties involved, but, like Japan, does not require notarization or legalization.

Unacceptable LOCs

In Japan, an LOC alone is not sufficient for acceptance. Applicants must also provide documentation showing no likelihood of confusion between the junior and senior trademarks; without this, the authorities will not accept an LOC. This requirement reflects Japan’s cautious approach to trademark coexistence and consumer confusion.

In contrast, South Korea strictly regulates LOCs, deeming both conditional and unconditional consents unacceptable. Generalized statements, such as “consent to all future trademarks,” and LOCs with limitations are prohibited. Instead, coexistence terms must be detailed in a separate agreement, ensuring a clear framework.

Double Identity Cases 

Both jurisdictions maintain a restrictive stance on LOCs in double identity cases—where identical trademarks are registered for identical goods and services—though their legal foundations differ. Japan does not accept LOCs for such cases, as the Japan Patent Office (JPO) presumes a high likelihood of consumer confusion.

Similarly, the Korean Trademark Act prohibits registering an identical trademark for identical goods, even with an LOC, reinforcing this inflexible stance. But South Korea’s prohibition is stricter, disallowing duplicate registration of identical marks for identical goods even if owned by the same entity. Both Japan and South Korea adopt firm policies against LOCs in double identity cases, focusing on preventing confusion and enforcing strict regulations.

Accelerated Examination

Japan and South Korea have differing approaches to LOCs concerning the eligibility for accelerated examination of trademark applications. In Japan, applications that include an LOC cannot be expedited, reflecting the JPO’s preference for thorough reviews over speed to avoid marketplace confusion.

In contrast, under South Korea’s trademark system, governed by Article 53 of the Korean Trademark Act, LOC applications are eligible for accelerated examination if they meet general criteria. This reflects South Korea’s commitment to streamlining the process, allowing for more efficient resolution of conflicts and registrations. These differences highlight Japan’s cautious, detailed examination of LOC applications versus South Korea’s faster, more flexible approach within its expedited trademark system.

Public Access

In Japan, trademarks registered via LOCs are fully searchable through the J-PlatPat database and are included in both the Trademark Gazette and the International Trademark Gazette. This transparency allows the public to verify that a junior mark has been registered with the consent of the senior mark holder, promoting clarity in trademark registrations.

In contrast, while South Korea displays the registration number of the senior mark alongside the junior mark, it does not provide access to the submitted LOCs. Instead, it offers information on the junior mark’s registration based on the senior mark’s consent, allowing the public to recognize the relationship between the two marks without revealing LOC specifics.

Both jurisdictions allow public access to trademark information, but Japan emphasizes transparency by providing direct access to submitted LOCs, whereas South Korea maintains confidentiality regarding LOC details.

Measures to Prevent Consumer Confusion

Japan and South Korea both have laws designed to prevent consumer confusion when similar trademarks coexist due to LOCs, but their approaches differ.

In Japan, the Trademark Act addresses potential confusion through Article 24-4, which permits parties to request measures to mitigate confusion when one trademark’s use may harm another’s business interests. Additionally, Article 52-2 allows any individual to seek cancellation of a trademark if it creates confusion with another’s goods or services for unfair competition. This framework underscores the importance of consumer clarity and business protection, even with LOCs.

South Korea similarly addresses consumer confusion in its Trademark Act. If a trademark registered with an LOC misleads consumers about the quality of goods or creates confusion with another party’s offerings, any individual can file a cancellation action. Article 119(1)5-2 also allows for the cancellation of the senior mark involved in misleading practices. This shows South Korea’s commitment to fair competition and consumer protection.

Differences and Similarities

While Japan and South Korea’s trademark laws share a common goal of allowing the coexistence of trademarks via LOCs, they differ significantly in their legal provisions, procedural requirements, examiner discretion, and transparency.

Japan’s system places greater emphasis on the submission of supplementary documentation to prove the absence of confusion and grants examiners more discretion in decision-making. South Korea, however, offers a more streamlined and less burdensome process for applicants, with fewer documentation requirements and a more definitive outcome upon submission of an LOC. These differences highlight the nuanced approaches of each country’s IP system in balancing trademark rights and preventing consumer confusion.

Although every effort has been made to verify the accuracy of this article, readers are urged to check independently on matters of specific concern or interest.

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