Under the Trademark Act, only registered trademarks are protected. Unregistered trademarks, no matter whether they are pending or not-applied-for trademarks, may be protected only if they are famous in Taiwan under the Fair Trade Act.

Practically speaking, it is not really easy to establish an unregistered trademark as famous in Taiwan, as a significant amount of evidence of use must be collected and submitted to prove that the trademark has been well known among the relevant enterprises or consumers. There are not any specific criteria for the necessary quantity of evidence. Whether a trademark may be deemed famous in Taiwan will be determined on a case-by-case basis.

In order to cancel the trademark registered in bad faith, it is possible to cite the claims of the famous trademark or earlier used trademark as legal basis under the Trademark Act.

As mentioned, it might not easy to collect evidence to establish the famous status in Taiwan. Another alternative is the claim of earlier used trademark against trademark registration in bad faith under the Article 30-I-(12).

Article 30-I-(12) of the Trademark Act stipulates that a trademark should not be registered under the situation that being identical with or similar to another person's earlier used trademark and to be applied for goods or services identical with or similar to those for which the earlier used trademark is applied, where the applicant with the intent to imitate the earlier used trademark, being aware of the existence of the earlier used trademark due to contractual, regional, or business connections, or any other relationship with the proprietor of the earlier used trademark, files the application for registration.

One of the controversial issues for such a claim is whether there is any quantity threshold of the earlier used trademark. The Trademark Act or the internal guidelines as set by the Intellectual Property Office (IPO, the Trademark Office in Taiwan) are silent on this issue.

The Intellectual Property Court held in opposition litigation in 2017 and sustained the IPO's decision that there is not quantity threshold for the claimed earlier used trademark. The requirement is that the trademark should be used in commerce in accordance with the Trademark Act. Accordingly, the use in an exhibition specifically in this case may be deemed trademark use according to the Trademark Act.