Utilization of Expert Knowledge in Patent Infringement Litigation (Makoto Hattori)
Since 2017, the International Symposium on Intellectual Property Courts (JSIP) has been held annually, co-hosted by the Supreme Court of Japan, the Ministry of Justice, the Japan Patent Office, the Japan Federation of Bar Associations, and the Intellectual Property Lawyers Network.
JSIP serves as an opportunity to communicate the realities of Japan’s intellectual property litigation system and operations both domestically and internationally, while also providing a platform to obtain direct insights from foreign practitioners on the practices in their respective countries. Each year, guest speakers from different countries—alternating between Western and Asian regions—are invited. The JSIP program consists of two parts the court session and the patent office session. In the court session which is organized by the judiciary participating countries including Japan conduct mock trials based on the same case scenario.
In 2024 the court session focused on the theme of claim interpretation and assessment of inventive step. Participants included the UPC (Unified Patent Court), the United States and the United Kingdom all of which conducted mock trials. Since the case scenario was somewhat favorable to the plaintiff all jurisdictions reached the same conclusion infringement was established and the patent was deemed valid. However, the reasoning process and trial procedures varied significantly among jurisdictions showcasing the unique approaches of each country which was highly insightful.
I have had the privilege of serving as counsel for the Japanese team in the mock trials four times (2018, 2019, 2021, 2024). Based on these experiences I would like to share some observations.
One characteristic of the Japanese team's mock trials, based on my experiences including this year, is the participation of judicial research officials and technical advisors in the court proceedings.
In Japan’s mock trial scenario judicial research officials and technical advisors take part in the proceedings directly questioning counsel on technical matters to help judges gain a deeper understanding of technical common knowledge. In contrast other jurisdictions rely on different mechanisms to incorporate technical expertise into judicial decision-making. For example, in the United States and the United Kingdom technical experts are retained ad hoc as expert witnesses while in Germany and the UPC technically trained judges are included as part of the judicial panel. It appears that Japan’s system of judicial research officials and technical advisors does not exist in these jurisdictions.
Judicial research officials are composed of patent examiners trial examiners from the Japan Patent Office and patent attorneys, involved in almost all patent-related litigation from the early stages conducting necessary research and providing expert insights to judges.
The technical advisor system was introduced in the 2003 amendment to the Code of Civil Procedure to enhance judicial decisions in litigation involving specialized and technical issues, such as intellectual property disputes (specialized litigation). Unlike judicial research officials, technical advisors are appointed ad hoc for each case from a pool of candidates. In procedures such as case management (primarily technical briefings), they are expected to provide explanations on the specialized technology at issue from the perspective of a neutral and impartial advisor to the court and the parties.
Both the judicial research official system and the technical advisor system have become deeply embedded in Japan’s patent litigation practice playing an essential role in ensuring fair and efficient judicial decisions.
However, on the other hand, it is unclear how judicial research officials influence the court’s formation of conviction, and technical advisors’ statements are not admitted as evidence, nor is there any provision for their cross-examination, making their role ambiguous. Therefore, some argue that expert testimony, which allows for cross-examination by the parties, should be conducted instead.
Certainly, in foreign jurisdictions, when technical matters are at issue, expert witnesses are appointed, and the parties conduct cross-examinations from various angles to assess the credibility of their opinions, which contributes to more precise judicial decision-making. Additionally, implementing such procedures is likely to enhance the parties’ sense of acceptance of the judgment to some extent. As a legal practitioner in Japan, I find it somewhat disappointing that such practices are almost never utilized. Since Japan’s Code of Civil Procedure provides for expert testimony, litigants should consider actively encouraging courts to utilize expert witness testimony instead of the technical advisor system, depending on the case. The background to the introduction of the technical advisor system includes difficulties in appointing expert witnesses, their lack of flexibility, and the high costs associated with expert testimony, which led to its limited use in the past. However, if appointing an expert witness is necessary for fact-finding, and if litigation participants can identify a suitable expert with the willingness to bear the costs, there is no reason to avoid utilizing expert testimony in such cases.
From the perspective of system users, having various procedural options available depending on the nature of the case is a significant advantage in practice.
After participating in the International Symposium on Intellectual Property Courts (JSIP), these are the impressions I have formed.
(Translated by Chaehyun Kim, RCLIP RA)