Using Letters of Consent: How to Resolve Similarity Conflicts in South Korea

For decades, South Korea was one of the few major trade mark jurisdictions that did not accept letters of consent as a means of overcoming similarity objections. When a trade mark application was refused for being similar to a prior mark under Article 34(1)(7) of the Korean Trademark Act (KTA), the only practical workaround was the cumbersome “assign-back” strategy: temporarily transferring one mark to the other party’s ownership, securing registration, and then reassigning it back. That changed on May 1, 2024, when a landmark amendment to the KTA introduced a formal consent agreement system that has already transformed Korean trade mark practice.

The Old System: The Assign-Back Workaround

Before the 2024 amendment, related entities sharing a house mark, or unrelated parties willing to coexist, had no direct mechanism to overcome a similarity citation. The assign-back approach required the applicant and the cited mark owner to temporarily place both marks under a single owner’s name, allowing the application to proceed without a similarity conflict. Once registered, the mark was reassigned back to its original owner.

This process was expensive, time-consuming, and legally risky. It required two recorded transfers (one to consolidate, one to reassign), government fees for each transfer, and potential complications with tax authorities and corporate governance. The introduction of the consent system eliminated this inefficiency.

The New Consent Agreement System: Articles 34(1)(7) and 35(6)

Under the amended KTA, when a trade mark application is refused based on similarity with a prior registered mark or prior pending application, the refusal can be overcome by submitting a letter of consent from the owner of the cited mark. The core rules are:

• Scope of application: The consent system applies to refusals under Article 34(1)(7) (similarity with prior marks). It does not apply to refusals based on similarity with well-known marks (Article 34(1)(9)), likelihood of confusion with famous marks (Article 34(1)(11)), or likelihood of misleading consumers about quality (Article 34(1)(12)).
• The identical-for-identical exclusion: A letter of consent cannot be used when the marks are completely identical and the designated goods or services are also identical. “Completely identical” in this context means precisely the same — even minor differences in font, colour, or composition may take the marks outside the exclusion, allowing consent to be submitted.
• No confusion assessment required: Unlike some jurisdictions (such as Japan), the KIPO examiner is not required to independently assess likelihood of confusion when a valid consent agreement is submitted. Unless the marks and goods are identical, the examiner must withdraw the citation upon receipt of the consent.
• Retroactive application: The consent system applies not only to applications filed after May 1, 2024, but also to all pending applications that had not yet received a final registration decision as of that date.

What the Letter of Consent Must Include

KIPO’s guidelines specify relatively simple requirements for the consent document:

• Identification of the junior application: The applicant’s name, KIPO customer number (or an explanation if one does not exist, such as for international registrations), and the application or international registration number.
• Identification of the senior mark owner: The name, KIPO customer number, and registration or application number of the cited mark.
• Clear statement of consent: An unambiguous statement that the senior mark owner consents to the registration of the junior application.
• Signatures of both parties.

Unlike Japan’s more elaborate system, Korea does not require the parties to submit evidence explaining why they believe confusion will not arise. The consent itself is treated as sufficient to resolve the similarity issue.

Restrictions: When Consent Cannot Be Used

The consent system has important limitations:

• Identical marks for identical goods: The most critical exclusion. If the applied mark is completely identical to the cited mark and the goods or services are also identical, no consent can overcome the objection.
• Well-known mark citations: Refusals based on similarity to a well-known or famous mark under Articles 34(1)(9) or 34(1)(11) cannot be resolved through consent.
• Consumer deception: Refusals based on the likelihood of misleading consumers about the quality of goods (Article 34(1)(12)) are outside the consent system.
• Conditional or blanket consent: KIPO does not accept consent agreements that include conditions such as time limits, geographic restrictions, or partial exclusions, as these are not enforceable by KIPO. Similarly, blanket consent for “all future applications” is not accepted; each consent must relate to a specific application.

Post-Registration Safeguards

The KTA includes an important consumer protection mechanism linked to the consent system. Under Article 119(1)(5bis), if a mark registered on the basis of a consent agreement is later used for unfair competitive purposes and causes consumer confusion or deception regarding the quality of goods, any person — not just the consenting party — can file a cancellation trial. If the registration is cancelled on this ground, the former registrant is prohibited from filing an identical or similar mark for identical or similar goods for three years from the date of cancellation.

This safeguard means that consenting parties should monitor each other’s use of the coexisting marks and take action if consumer confusion actually materialises.

Early Results: Rapid Adoption

The consent system has been embraced rapidly. According to KIPO’s statistics, over 600 consent agreements were submitted in the first six months following the May 2024 implementation. In the vast majority of completed examinations, the similarity refusal was successfully overcome. This early data confirms that the system is functioning as intended and is being applied by examiners in a straightforward manner.

Strategic Recommendations

• Approach the cited mark owner early: If a pre-filing search identifies a potential conflict, consider reaching out to the prior mark owner before filing. Having a consent agreement ready can prevent or quickly resolve a similarity citation.
• Confirm the marks are not completely identical: If the marks and goods are both identical, consent will not work. Consider any modification — even a minor design difference — that takes the application outside the exclusion.
• Use consent during appeal proceedings: Consent agreements can be submitted at any stage up to and including appeal before the IPTAB (but not before the Intellectual Property High Court). If an appeal is pending against a similarity refusal, consent can still resolve the issue.
• Monitor post-registration use: Senior mark owners who consent should monitor the junior mark’s use to ensure it does not create actual confusion or unfair competition. The cancellation safeguard provides a remedy if problems arise.
• Keep the consent unconditional: Do not include conditions, geographic restrictions, or time limits in the consent submitted to KIPO. These render the consent unacceptable. Any additional commercial terms should be documented in a separate private agreement between the parties.

Common Mistakes

• Attempting consent for identical marks on identical goods: This is the one scenario where consent cannot help. Verify that the marks and goods are not both completely identical before pursuing this strategy.
• Including conditions in the KIPO consent: Conditional or blanket consents are rejected. The KIPO submission must be a straightforward, unconditional consent for the specific application.
• Assuming consent works for well-known mark citations: The consent system is limited to Article 34(1)(7) refusals. It does not cover well-known or famous mark objections.
• Waiting too long to negotiate: The response period for office actions is limited. Begin negotiations with the cited mark owner promptly upon identifying the potential conflict.

Key Takeaway

The introduction of the consent agreement system on May 1, 2024 was one of the most significant reforms in Korean trade mark law in recent years. It eliminates the need for the costly and cumbersome assign-back workaround and provides a straightforward mechanism for resolving similarity conflicts. With over 600 consent agreements filed in the first six months and a high success rate, the system has been rapidly and successfully adopted. For applicants facing similarity citations, consent should now be the first strategy considered — subject to the important limitations on identical marks and well-known mark citations.