Japan Draws a Legal Line Around the Human Voice

Japan has now done what lawmakers everywhere like to postpone until the copying becomes too obvious to ignore: it has told a platform that a voice is not merely data to be scraped, imitated and sold back to the public. In Tokyo, the district court ruled that unauthorised use of a performer’s voice can amount to an infringement of publicity rights when the point is to exploit its commercial appeal. That may sound like a technical distinction. It is, in practice, a reminder that identity is still supposed to belong to someone.

The case was brought by Kenjiro Tsuda, 55, one of Japan’s best-known voice actors and the man behind Kento Nanami in Jujutsu Kaisen. He argued that 188 TikTok videos posted on an anonymous account between July 2024 and September last year used an AI-generated voice so close to his own that it amounted to cloning. The account paired images resembling Tsuda’s character with synthetic speech about urban legends, the occult and conspiracy theories, and at one point had more than 200,000 subscribers. According to the legal complaint reported by Kyodo, the clips would have earned the account owner between ¥500,000 and ¥75,000 in monthly revenue.

The court did not order TikTok to remove the videos, because the user had already deleted them after the suit was filed in November. That left Tsuda without the practical remedy he wanted, but not without a ruling that matters. Presiding judge Aya Takahashi said the unauthorised use of a performer’s voice can be considered an infringement of publicity rights, and that a voice is as symbolic of personality as a portrait. In other words, the law has finally noticed what the entertainment industry has long understood: a recognisable voice is not an incidental feature, but part of the product.

This was the first Japanese court decision to say explicitly that a human voice is protected under publicity rights. For voice actors, that is not a minor doctrinal flourish. Japan’s performers often become stars through their “appearances” in anime, and many now fear that AI mimicry could erode both livelihoods and an entire profession built on training, timing and distinctive delivery. Yuko Sasaki, executive director of the Japan Actors Union, said before the verdict that an actor’s voice is the result of years of rigorous training and apprenticeship.

TikTok said it would respect the judgment while considering what steps to take after examining the details, and added that it would continue working on the balance between technological development and rights protection. The formula is familiar enough to be almost soothing. The difficulty, as ever, is that platforms tend to discover the value of balance only after someone else has paid for the imbalance.

The ruling also gives weight to a broader campaign by Japanese actors. In 2024 they launched “No More” to oppose the unauthorised use of their faces and voices in AI-generated content. Tsuda’s case now gives that effort a legal foothold. It also sends a clear signal that the old assumption — that a performer’s voice can be copied if the software is clever enough — is beginning to meet the law, which remains a useful habit in a country that has finally decided to ask who owns a voice.

Written by Thomas Nussbaumer thomas.nussbaumer@alpineweekly.com