Patent laws in the region vary in their effectiveness. Regulations across jurisdictions to crack down on infringers are in a constant state of renewal and revision in order to stay ahead of those who steal intellectual property. Keeping the trolls at bay depends on staying abreast of regional developments in patent law

Regional comparison of patent law (Click to enlarge image)


China | India | Japan | Singapore | Sri Lanka | Taiwan | The Philippines


For various reasons, Japan has been known as a unique country that has seen much less active patent litigation activity by patent trolls despite the wide variety of cutting-edge electronics and computer businesses within Japanese corporations. The same can also be found happening to pharmaceutical patents too. However, PAEs (patent asserting entities), also known as “patent trolls”, do not easily give up on chasing Japanese corporations.

Kozo YabePartnerYUASA and HARATel: +81 (3) 3246 6513Email:
Kozo Yabe
Tel: +81 (3) 3246 6513

It is apparent that PAEs are aware of some of the difficulties in undertaking patent infringement actions in Japan due to the procedural characteristics of Japanese civil procedure under the Civil Procedure Code and the Patent Act.

In Japan, even a complaint needs to specify the patentee’s assertion and causes in detail, in comparison with the practice in the US. The complaint needs to contain at least a specification of the subject product/method infringing the patent, with a precise explanation of the technical application and legal interpretation. Some basic written evidence must also follow such content of the complaint.

In addition, Japanese civil procedure has no fully functional discovery procedure, unlike the US. Instead it relies on the functional limitations of document submission orders, etc. Japanese courts, especially the Tokyo District Court and Osaka District Court, which have special jurisdiction over patent infringement cases, carefully check any petitions to be filed by a plaintiff as a patentee. The judges are mostly law graduates but are trained for intellectual property cases at the special IP divisions of these district courts, and are well assisted by technical researchers who are mostly former JPO examiners and patent attorneys.

Such “well scrutinized” complaints and evidence inevitably influence, however slightly, the slow decision-making in preliminary injunctions. It is not uncommon for a patentee to see a preliminary injunction ordered by the court several months after filing the petition. This differs greatly from the US and Germany, which are more expeditious by comparison. Although there are other reasons, these are perhaps the procedural obstacles for PAEs to overcome in undertaking official patent infringement litigation in Japan.

Even though PAEs are aware of some of the difficulties in taking action, especially in courtrooms, in Japan they still have an active presence. This is because PAEs may avoid formal scrutiny of their patents and technical weakness if they repeatedly approach Japanese corporations. Of course, these corporations may take counter action measures by going to the Japan Patent Office (JPO) for patent invalidity procedures even before they need to begin making any defence of patent invalidity in the courtroom.

Nevertheless, the JPO’s procedures are precise and well scrutinized. In such cases, even a petitioner of a patent invalidity at the JPO needs to prepare a good set of briefs and evidence supported by well constructed technical analysis and legal causation. Otherwise, PAEs may still win their cases and enhance the foundation of the patent by amendment. Accordingly, PAEs still try to balance their efforts with seemingly soft yet tenacious negotiations with Japanese corporations, even though they risk possible invalidity actions at the JPO. What this means is that even some targets of foreign corporations, as well as Japanese corporations, may utilize the JPO’s functions to defend themselves if they have a reliable set of evidence prepared.

Even though Japanese civil procedure does not look so appealing to PAEs, they still bring their cases before Japanese courts as part of their global litigation strategy. It is common for a patentee to take advantage, as much as possible, of each country’s procedures, and to then combine such advantages in order to finally win a case.

PAEs are not exceptional. Some PAEs file patent infringement cases at almost the same time, or within a close timeframe, as the US, Germany or other appropriate European countries such as the U.K. and Netherlands, and Japan. By doing so, they aim to impose the immediate threat/pressure of preliminary injunctions on Japanese corporations in the US and/or Germany as they seek to find suitable evidence of infringement in the civil procedure in either of these countries.

PAEs may still sight a canon towards the head offices of Japanese corporations in Japan while simultaneously having the chance to claim victory in patent infringement cases, provided they can find suitable supporting evidence via procedures in other countries. If they obtain a Japanese preliminary injunction order or judgement with precise analysis of technical points and legal interpretation, this will assist their actions further. However, once PAEs understand how Japanese judges frown upon patent infringements, they are usually quick to withdraw their complaints and abandon all claims based on the subject patents. This is the typical attitude of PAE patent litigation in Japan, and may be a reason why it is difficult to determine just how active PAEs are in Japanese courts.

In any case, PAEs are free to roam anywhere they like in their quest to seek out potential business opportunities. Just remember that Japan is not exempted from the attentions of PAEs.


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