2023 (Gyo-Ke) 10069 [Soldering Apparatus] <Hibiku Shimizu> — Inventive-Step Assessment and Scope of Res Judicata
Updated: 6 hours ago
Article information
Article type: Case note
Category: Patents
Topics: Inventive step
First published on this website: 2026-11-01
Display and classification checked: November 2, 2026
Originally published on Ameblo: 2024-10-21 (Japan time). Full English translation.
2023 (Gyo-Ke) 10069 [Soldering Apparatus] <Hibiku Shimizu>
*Inventive-step assessment: scope of res judicata
Although there were points the first judgment did not decide, inventive step is a legal determination based on identification of the invention and cited invention and their common features and differences.
The binding effect of the first judgment prevents the trial examiners from finding different facts and making a different determination.
“In light of the purpose of the Supreme Court Grand Bench judgment of March 10, 1976 …, res judicata attaches not to the absence of illegality in the trial decision generally, but to the absence of illegality in the decision on inventive step based on the invention (publicly known technology) described in the particular reference examined in the patent invalidation trial.”
(Excerpts from the court's reasoning)
In light of the purpose of the Supreme Court Grand Bench judgment of March 10, 1976 (1967 (Gyo-Tsu) 28), Minshu Vol. 30 No. 2, p. 79, it is appropriate to understand that the res judicata effect of a judgment dismissing a claim in an action to set aside a decision in a patent invalidation trial concerning inventive step attaches not to the absence of illegality in that decision generally, but to the absence of illegality in its determination of inventive step based on the invention (publicly known technology) described in the particular reference examined in the invalidation trial.
Applying this to the present case, as found above, the first judgment (the portion dismissing the plaintiff's claim; the same applies below) held that Invention 4 could not be said to have been readily invented before filing by a person skilled in the art based on the cited invention in Exhibit Ko 1. It upheld the first trial decision to the same effect and dismissed the plaintiff's claim. Because that judgment subsequently became final, the absence of illegality in the first trial decision, which held that Invention 4 could not be said to lack inventive step based on the cited invention in Exhibit Ko 1, must be regarded as conclusively established with res judicata effect.
The issue here is the illegality of the present trial decision, not the first trial decision. However, the plaintiff's assertion in this action that Invention 4 lacks inventive step based on the cited invention in Exhibit Ko 1 (Ground for Cancellation 3), and that the portion of the present decision denying lack of inventive step is unlawful, substantively seeks a different determination on the part concerning illegality of the first trial decision that is subject to res judicata (the determination that inventive step cannot be denied on the basis of the same cited invention). This must be regarded as impermissible.
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November 1, 2026: First published on this website.
November 2, 2026: Added article information, classification, topics, language navigation, related articles where the same case was confirmed, consultation guidance, and SEO. The original text and first-published date were preserved.
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