Trademark Dilution in Japan

46 Pages Posted: 8 Nov 2005

See all articles by Kenneth L. Port

Kenneth L. Port

Mitchell Hamline School of Law; William Mitchell College of Law

Date Written: November 2005


Trademark dilution jurisprudence in Japan is in a state of confusion. In an otherwise highly rational, highly developed system, this scattered jurisprudence is unexpected. It may be that Japanese courts, much like American courts, are reticent to recognize the full scope of the dilution right or it may be that the cause of action is still too new. The confused status of Japanese trademark dilution law, however, is indicative of a judiciary that is at odds with the legislature. This scattered jurisprudence is not scattered because of a lack of technical skill by the judiciary. It is likely scattered for greater reasons: to rein in a right the judiciary sees as inconsistent with the purposes of trademark protection in Japan.

This article directly addresses the paucity of trademark dilution cases in Japan. This article concludes that first, to be sure, there are probably more cases than get reported (although that number is probably negligible). Second, the statute is even more vague than most Japanese legislation and does not even use the word dilution. Japanese courts do not or cannot distinguish between fundamental elements of the cause of action. Third, the defensive trademark system, underutilized as it is, provides an alternative to dilution protection. Finally, the theoretical understanding of trademark law renders dilution claim superfluous.

In the aggregate, the result is a system that is very unsure of the dilution cause of action. This lack of certainty may prevent some entities from recognizing and pursuing their rights under the statute. To be sure, the confused state of Japanese dilution protection clearly indicates that Japanese courts do not understand the cause of action or are reticent to apply it as it is written. Given the high degree of technical skill of Japanese judges, it is not likely that they are simply making serious errors when applying dilution law to any given set of facts.

Keywords: Dilution, Japan, Trademark

Suggested Citation

Port, Kenneth L., Trademark Dilution in Japan (November 2005). William Mitchell Legal Studies Research Paper No. 30. Available at SSRN: or

Kenneth L. Port (Contact Author)

Mitchell Hamline School of Law ( email )

875 Summit Ave
St. Paul, MN 55105-3076
United States


William Mitchell College of Law ( email )

875 Summit Ave
St. Paul, MN 55105-3076
United States


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