Voice cloning may infringe rights: Tokyo court points to commercial use

The commercial test. The court recognized that using a voice without permission solely for its ability to attract customers may infringe publicity rights. These rights protect the commercial value of a person's identity. The court did not rule on the remaining disputed issues, including whether the specific videos infringed those rights.

The dispute concerned 188 videos about urban legends and paranormal phenomena featuring an alleged AI replica of the voice of Tsuda, who voiced Kento Nanami in Jujutsu Kaisen. The account posted them from July 2024 to Sep 2025. In Nov 2025, it had more than 210,000 followers.

According to lawyer Kei Hirano in a Sep 30 report by Bengo4.com, the videos averaged around 1.47 million views, with estimated revenue of about ¥700,000 per month. To demonstrate the similarity between the voices, Tsuda's legal team used several deep learning models for audio analysis. The source code of the comparison program was also submitted to the court.

Deletion ended the dispute. In Aug 2025, Tsuda obtained a court order to disclose information about the account's creator, but the creator could not be identified: the retention period for logs associated with the disclosed IP address had already expired. The creator deleted the account on May 29, 2026. After 30 days without a request to restore it, TikTok deleted its data by the end of June 28.

Tsuda originally sought removal of the videos rather than monetary compensation. According to Hirano, deleting the account achieved the lawsuit's goal.

Tsuda's side does not plan to appeal.