Japan-Korea AI Manga Piracy Case

In May 2026, the Tokyo Metropolitan Police arrested Kenzo Tanaka, a Japanese systems engineer, and indicted South Korean AI firm NexaMind AI and its CEO Park Joon-young for large-scale copyright infringement. NexaMind illegally obtained over 50,000 pages of copyrighted manga from Japanese publishers like Kodansha by bribing Tanaka to bypass server security. The data was used to train an AI model, "MangaMind," launched in Korea, generating images mimicking the distinct styles of famous artists, causing significant financial damage in Japan. The investigation, assisted by Interpol, escalated into a diplomatic issue, with Japanese authorities issuing an arrest warrant for Park and pursuing the company for damages under Japan’s Copyright Act, which prohibits unauthorized AI training on protected works.

As of the latest hearing in late 2026, the Tokyo District Court found Kenzo Tanaka guilty of unauthorized access and copyright violation, sentencing him to 3 years in prison and a 2 million yen fine. The trial for NexaMind AI and CEO Park proceeded in absentia. The court issued a landmark preliminary injunction forcing NexaMind to dismantle the MangaMind model trained on infringing data and de-index it globally. A final ruling on damages, potentially reaching billions of yen, is pending, while South Korea cooperates under a mutual legal assistance treaty.

The core dispute is whether using pirated copyrighted materials for AI training constitutes a separate, aggravated offense beyond traditional piracy, and the extraterritorial application of Japan's amended Copyright Act over a foreign AI company. The defense argued the AI-transformed images fall under "fair use" or are non-infringing "learning," while the prosecution emphasized the criminal intent behind the initial data breach and the commercial nature of the resulting service, setting a critical precedent for the "ingestion phase" of AI development.

The case sent shockwaves through the creative industries, accelerating Japan's push for stricter AI transparency laws. It sparked a massive "No AI Theft" movement among manga artists globally and chilled unlicensed data scraping by AI firms. The arrest deepened cultural tensions between Japan and South Korea over IP protection standards, but also initiated a bilateral task force on regulating cross-border AI development. It set a powerful global warning that training AI on pirated content carries severe criminal and financial risks.