Nintendo’s lawyer weighs in on what makes emulators illegal

During the Tokyo eSports Festa 2025 held from January 10 to 12, Nintendo participated in a conference jointly organized by the Japan Computer Software Copyright Association (ACCS). Koji Nishiura, patent attorney and deputy general manager of Nintendo’s Intellectual Property Department, spoke on behalf of Nintendo on the topic “The Importance of Intellectual Property Rights in the Gaming Industry.” “To begin with, are emulators illegal or not? This is an often debated point. While one cannot immediately say that an emulator is illegal in itself, it can become illegal depending on how it is used. is used,” Nishiura explains. If an emulator copies a program owned by the game console it is imitating, this may constitute copyright infringement. If the emulator has a function that disables security mechanisms such as encryption (legally called “technical protection measures”), this may be considered a violation of Japan’s Unfair Competition Prevention Act, according to Nishiura (he mentions that outside of Japan the latter is likely to be stipulated in copyright law).

Citing another example of illegal use, Nintendo’s lawyer explains that if an emulator contains links to sources where you can download pirated games, it can be considered a “scope application” under Japanese law, and therefore constitute a violation of copyright. Nishiura mentions that Nintendo filed lawsuits and issued warnings in the United States and other countries regarding several Switch emulators due to the second point mentioned here: they contained mechanisms that disabled Nintendo’s technical protection measures.