Avoiding Conflicts: How the JPO Evaluates Similarity under Article 4(1)(xi)

When a trade mark application conflicts with an existing registration or prior application, the JPO refuses it under Article 4(1)(xi) of the Trademark Act. This is the standard relative grounds refusal — and the way the JPO assesses similarity has distinctive features that foreign applicants must understand, particularly the heavy weight given to phonetic similarity in the Japanese language.

The Legal Basis

Article 4(1)(xi) provides that no trade mark shall be registered if it is identical with, or similar to, another person’s registered trade mark that was filed before the application date, where the marks cover the same or similar goods or services. The JPO examines every application ex officio against the register, and will issue a notification of reasons for refusal citing any conflicting prior marks.

The Three Pillars of Similarity

The JPO assesses similarity by comparing marks across three dimensions, often referred to as the “global comparison”:

Appearance (Gaikan — Visual Similarity)

This examines the visual impression of the marks: the structure, letter arrangement, character composition, design elements, and overall look. For word marks in Roman letters, the examiner considers shared letter sequences and overall length. For marks in Japanese script, the number of characters, their visual complexity, and overall configuration are assessed.

Pronunciation (Shōko — Phonetic Similarity)

This examines how the marks sound when spoken. In Japan, phonetic similarity carries particular weight because Japanese consumers frequently encounter, recall, and communicate about brands orally. The assessment considers pronunciation in Japanese, including the Katakana transliteration of foreign words.

Japanese has approximately 160 distinct sounds, compared to significantly more in English. This limited sound inventory means that many foreign words converge on identical or near-identical Japanese pronunciations. As a result, two marks that look very different in their original languages may be found phonetically identical in Japanese. This phenomenon is discussed in detail in a separate article on the Katakana barrier.

Meaning (Kannen — Conceptual Similarity)

This examines whether the marks convey the same or a similar idea. If both marks evoke the same concept — for example, a word meaning “mountain” in English and the Kanji character for “mountain” — they may be found conceptually similar even if they look and sound different.

The Weight of Phonetic Similarity

While the JPO considers all three dimensions, phonetic similarity alone can be sufficient to sustain a refusal. This is a critical difference from many Western jurisdictions, where visual or conceptual differences might offset phonetic overlap. In Japan, a finding of phonetic similarity is often treated as the dominant factor, particularly for word marks.

This reflects the reality of how Japanese consumers interact with brands: through conversation, word-of-mouth recommendations, and oral requests at retail counters. Marks are often communicated verbally before they are seen visually.

The JPO’s emphasis on phonetic similarity also interacts with the Katakana transliteration issue (discussed in a separate article). When foreign-language marks are transliterated into Japanese, the limited sound inventory of the language means that many distinct foreign words converge on identical Katakana readings. This amplifies the phonetic dimension of the similarity test for foreign applicants.

The 2024 Consent System

Until recently, Japan did not accept letters of consent to overcome similarity objections. Two similar marks owned by different parties could not coexist on the register, even with mutual agreement. The only workaround was an “assign-back arrangement” in which the applicant temporarily assigned the application to the cited mark owner.

A 2024 amendment to the Trademark Act introduced a consent system for applications filed on or after April 1, 2024. A consent letter from the cited mark owner may now overcome a likelihood of confusion refusal, provided the consumer is likely to distinguish between the two marks. However, the JPO has indicated that the consent must demonstrate that confusion will not occur now or in the future, and the standard for acceptance remains to be fully established in practice.

Responding to a Similarity Refusal

When the JPO issues a notification citing a prior mark, the applicant typically has three months (extendable by three additional months for non-residents) to respond. Strategies include:

• Arguing dissimilarity: Present detailed arguments on visual, phonetic, and conceptual differences.
• Letter of consent: For applications filed from April 2024 onward, submit a consent letter from the cited mark owner.
• Narrowing the specification: Amend the goods or services to eliminate overlap with the cited mark.
• Non-use cancellation: If the cited mark has not been used for three consecutive years, file a non-use cancellation trial to remove the obstacle (discussed in a separate article).

Strategic Recommendations

• Conduct phonetic searches in Katakana: A clearance search using only Roman characters is insufficient. Search using the Katakana transliteration of your mark to identify potential phonetic conflicts.
• Use the J-PlatPat database: The JPO’s free online platform allows searching by Katakana reading and similarity group code — essential for identifying conflicts.
• Plan for the phonetic dimension: If your mark sounds similar to an existing mark when pronounced in Japanese, anticipate a refusal and prepare your response strategy in advance.
• Consider the consent system: For new filings, explore whether the cited mark owner would be willing to provide consent under the new system.

Key Takeaway

The JPO’s similarity assessment is built on visual, phonetic, and conceptual comparison, but phonetic similarity carries disproportionate weight. Foreign brands must assess how their marks sound in Japanese — not just how they look. The 2024 consent system offers a new tool for resolving conflicts, but its practical scope remains to be tested. For now, the most effective strategy is thorough phonetic searching in Katakana before filing.