2000–2001 Defense of Japanese Company’s EPO Patent Opposition

In this case, we represented the interests of a medium-sized Japanese company in Europe.

Our client, a medium-sized Japanese chemical manufacturer, invented and held patents for a unique fluorescent material in Japan and several other countries.

Chinese companies had similar technologies. Our client had a Chinese competitor who exported similar products to Europe. After our client’s patent was registered with the European Patent Office, opposition to it was filed by a large company in Europe, a distributor of the above-mentioned Chinese products.

Most of the exhibits were the affidavits certifying that the invention was publicly known in China. For example, one of the exhibits was a written testimony, with the seal of the person in charge at the administrative agency in Hong Kong, stating that such fluorescent material was seen displayed at an exposition in Hong Kong before the patent application. More than twenty exhibits of this sort were submitted to the opposition division of the European Patent Office.

Initially, we were quite confused about having obtained duplicates of such exhibits. We imagined those exhibits had probably embarrassed the opposition division of the European Patent Office even more. Furthermore, such exhibits kept coming in continuously and during the trial examination for the European Patent Office’s opposition.

In most of the oppositions to grant a patent at the European Patent Office, an oral hearing is held. One was scheduled for this case, so the client company’s general manager, myself, a patent attorney for the European Patent, and a German attorney got together in Dusseldorf one week before the hearing to prepare.

The oral hearing was held all day at the trial court in the European Patent Office’s headquarter building in Munich. We won the case entirely without any restriction of the claim due to amendment.

The trial examination’s collegial body at the European Patent Office stated that such exhibits could not rationally prove the opposition. It denied the evidential capacity of all the exhibits. As a result, the opposition was turned down without demonstrating the lack of novelty and inventive step of the client’s invention.

It turned out that this case was one which the European Patent Office had never dealt with before, and it became quite well known at the time in Europe.

From this case, we learned that the exhibits mentioned above became effective in China at that time with the seal of the administrative agency’s government official. When the opposition filed and took rather long to deal with the case, the European attorneys took a negative view of the situation.

However, in the end, the European Patent Office made a fair judgment, and our worries proved unfounded. We learned the importance of maintaining a positive mindset and taking the related parties’ leadership to guide them appropriately from this experience.


Success Stories


2007-2009 Prevention of American Patent lawsuit and Invalidation Trial (Damages Settlement)


2018-2020 Utility Model Invalidation Defense at Three Levels Of Court (Damages Settlement)


2018–2020 Protecting Local Companies’ Trademark Rights in Japan


1995–1998 Defending French Patent Rights in Japan (Breaches of Contract Resolutions)