[Employee inventions] Tokyo District Court, Reiwa 5 (Wa) 70495 <Presiding Judge Nakashima>
更新日：10月3日
Article information
Article type: Case note
Classification: Patents
Issues: Employee inventions
First published on this site: 2026-10-03
Court: Tokyo District Court
Case number: Reiwa 5 (Wa) 70495
Display/classification checked: 2026-10-03
[Employee inventions] Tokyo District Court, Reiwa 5 (Wa) 70495 <Presiding Judge Nakashima>
* Joint inventorship not established.
The plaintiff could not establish when the invention had been completed.
(Excerpts from the judgment, translated)
The plaintiff argued that the plaintiff's invention had been completed before the explanatory document was prepared, but there was no adequate supporting evidence. In any event, the invention at issue had been conceived and made concrete without the plaintiff's involvement.
After two rounds of allegations and proof by both parties, the actual nature of the plaintiff's involvement remained unclear. The court therefore twice sought clarification from both parties. Even after fully considering the results, the invention, in light of the actual circumstances of the plaintiff's involvement, had been conceived and made concrete without that involvement. The plaintiff could not be recognized as an inventor or joint inventor.
Revision history
Revision history is maintained by appending entries.
2026-10-03: First published on this site; classification, article information, and consultation link added.
