In Japan, the Trademark Consent System was introduced in April 2024.
This section explains the introduction of the Japanese Trademark Consent System and the problems it faces.

1. Introduction
The Trademark Law provides may not be registered if the applicant has applied for registration if a trademark registered by another person (hereinafter referred to as a "previously registered trademark") or a trademark similar thereto, in respect of the designated goods or designated services pertaining to such trademark or something similar thereto (Article 4(1)(xi) of the Trademark Law).

2. Conventional response (Assign back)
In this case, other countries have introduced a consent system whereby the grounds for refusal are eliminated if consent is obtained from a predecessor, but Japan has not introduced a consent system because allowing the coexistence of identical or similar trademarks only by obtaining consent would lead to confusion of origin.
Then, in practice, this has been handled by assignment back. Assign-back is a method whereby, when a notice of reasons for refusal is received from the Patent Office, the subject trademark application is assigned to the prior trademark owner, thereby resolving the reasons for refusal, and the subject trademark is then assigned to the applicant. This method has been used in practice and is not stipulated in the Trademark Law.

3. History of the introduction of the consent system
Many other countries have a consents system unlike Japan.
In the case of large companies, a global agreement may be concluded to consent to the parallel registration of a trademark. In such cases, the procedures in Japan differ from those in other countries, and foreign companies have complained.
Furthermore, in order to encourage new business development using intellectual property by small, medium and start-up companies, etc., it is necessary to broaden the range of brand choices for new businesses.
In addition, as the conventional assign-back is an exceptional method, which is not stipulated in the law, and there is uncertainty as to whether they will assign their trademark rights after registering them concurrently, as well as a reasonable burden in terms of assignment negotiations and assignment costs, the introduction of a consent system has been awaited.
There are two types of consent systems: a complete type of consent, which requires only the submission of a consent form (this is the type of Korean consent system into effect in May 2024), and a reserved type of consent system, which allows concurrent registration after the submission of a consent form and examination by the Patent Office as to whether there is any confusion of origin or not.
Japan has adopted the reserved type of consent system.

4. Points to note on the Consent System

(1) Designated goods or designated services subject to the Consent
The designated goods or designated services which are the subject matter of the consent will be subsequently determined as to whether there is confusion of origin.
Therefore, the designated goods or services subject to the Consent System are, within the designated goods or designated services pertaining to both trademarks which are considered to be identical or similar to each other in the determination under Article 4(1)(xi), goods or services in which the applicant actually uses or intends to use the applied for trade mark, and goods or services in which the holder of trademark right, exclusive right to use or non-exclusive right to use in relation to the registered trade mark of another person under the same item actually uses or intends to use the registered trade mark.

(2) Under the Consent System, the likelihood of confusion is determined after the submission of the consent form. The first application is not only for trademarks that have been used, but also for unused trademarks. If the first application is for an unused trademark, the fact that the first application is not being used at the present time and whether the first application will be used in the future is taken into account as a factor when determining the likelihood of confusion.

(3) There is no provision to the effect that concurrent registration is not possible in the case of the same trademark and the same designated goods or services by means of an outlet. On the other hand, there are no provisions on how to deal with cases of identical trademarks in the post-processing of concurrent registrations, such as requests for indication of prevention of confusion (Article 24-4) and trials for cancellation of unfair use (Article 52-2). These are considered to be the intent of not allowing concurrent registrations. In the opinion of the Office, there is a high risk of confusion in the case of identical trademarks, and the direction is likely to be to disallow concurrent registrations.

(4) Consent is required at the time of assessment. Fear of confusion may arise in the future and a decision will be made on future fear of confusion.
Note that confusion there includes even confusion in the so-called broad sense of the term. In other words, confusion includes not only the risk that consumers of the goods, etc. may be confused as to the origin of the goods, etc., but also if they misidentify the goods, etc. as belonging to the business of a person who has some economic or organizational connection with the holder of the trademark right, exclusive right to use or non-exclusive right to use in relation to the registered trademark of the other person.

(5) Please refer to the Patent Office examination criteria for a detailed description of the form of the agreement and the determining factors such as the existence of confusion.

https://www.jpo.go.jp/e/system/laws/rule/guideline/trademark/kijun/document/index/0319.pdf

5. Points to note after concurrent registration

(1) Risk of receiving an anti-confusion indication claim.
Even after a concurrent registration by the Consent, if the use of the registered trademark is "likely to harm the business interests" of the other registered trademark, the trademark owner or exclusive right to use of the other registered trademark may demand an indication of anti-confusion to be added to the additive part of the trademark, which is distinguishable in some way.

(2) Furthermore, if the registered trademark is used for the purpose of unfair competition and causes confusion of origin, it is also subject to a cancellation trial under Article 52bis.  This trial is a sanction and the entire trademark right is cancelled, not just the designated goods or services that have been misused, so care must be taken when using the trademark.

6 Future

The Japanese Consent System was adopted as a simpler system than the traditional Assign-Back system, which is not a full Consent system with only a consent form, but a system where even the existence of source confusion is determined afterwards. It should be quicker and simpler, but it remains to be seen how the review process will work in practice.