Masabumi Suzuki has posted a paper on ssrn titled Recent Trends Concerning Article 102 of the Japanese Patent Act - Court Judgements and Law Amendments Relating to Calculation of Damages for Patent Infringement, Patents and Licensing, No. 291, pp. 8- 24 (2021). Here is a link to the paper, and here is the abstract:
The current Japanese Patent Act has set forth special provisions on the calculation of damages since the time of its enactment (1959). Nevertheless, it had been constantly criticized that appropriate remedies were not being extended to right holders by the compensation for damage even under those provisions due to reasons such as the court applying the provisions too rigidly. In response, the provisions related to compensation for damage were amended in 1998. Specifically, Article 102, paragraph (1) of the Patent Act was introduced, and the wording of paragraph (3) of that Article was revised. However, even after the amendment, active discussions took place among practitioners and researchers over the interpretation of the provisions, and legislative studies were continued. Then, in the past few years, three Grand Panel judgments (en banc decisions) of the Intellectual Property High Court (IP High Court) indicated a general view on some issues for which opinions had been varied among court judgments, achieving a unified interpretation of the provisions at least on the second instance level. In addition, in 2019, Article 102 of the Patent Act was amended again. With such progress, the developments concerning the system of compensation for damage caused by patent infringement are regarded to have reached a milestone. This article introduces the outlines of those IP High Court Grand Panel judgments and the 2019 law amendment. In addition, it conducts analysis with a focus on the latest Grand Panel judgment rendered in the Beauty Instrument case.
I very much enjoyed reading this paper, which discusses three important Grand Panel decisions of the past decade (Judgment of Feb. 1, 2013, 2012 (Ne) 10015, Judgment of June 7, 2019, 2018 (Ne) 10063, Judgment of Feb. 28, 2020, 2019 (Ne) 10003), as well as a good deal of Japanese scholarly commentary that is not available in English translation. Highly recommended.