Nintendo attorney explains why it's strengthening measures against illegal emulation

"This is a point often debated."

An attorney for Nintendo has discussed the company's stance on emulation and what it considers to be illegal, according to Japanese law.

Koji Nishiura, patent attorney and deputy general manager of Nintendo's intellectual property department, spoke on behalf of the company at a joint lecture on "The Importance of Intellectual Property Rights in the Game Industry", which was hosted by Japan's Association of Copyright for Computer Software at the Tokyo eSports Festa 2025 (Denfaminicogamer, via Automaton).

"To begin with, are emulators illegal or not?" posed Nishiura. "This is a point often debated. While you can't immediately claim that an emulator is illegal in itself, it can become illegal depending on how it's used."

One example of illegal use is if an emulator copies a programme belonging to the game device it's imitating, which would be copyright infringement.

Another is if an emulator can disable security mechanisms like encryption (or "technical protection measures", as they're legally known), which would violate Japan's Unfair Competition Prevention Act. Nishiura added that outside of Japan this would be stipulated in copyright law.

Nishiura specified this point is why Nintendo has filed lawsuits and issued warnings over several Switch emulators, due to disabling Nintendo's "technical protection measures".

A further violation would be if an emulator contains links to sources to download pirated games, what's known as a "reach app" in Japanese law and is considered a copyright infringement.

Nishiura also emphasised the use of emulators is a problem for all developers making software for Nintendo devices, which is why the company is strengthening measures against such illegal tools.

Just last year, Nintendo sued the creators of Switch emulator Yuzu as it claimed over a million copies of Zelda: Tears of the Kingdom were pirated ahead of release. Yuzu was then shut down by its developers Tropical Haze and agreed to pay Nintendo $2.4m.

Also last year, the Game Boy emulator Pizza Emulators was pulled from the Google Play store, though there was no mention of a Nintendo settlement. A month later, another Nintendo emulator - the Delta app - was the top free download on the iPhone App Store and it remains available today.

In further Nintendo news, the company has also requested players not use "unauthorised services" to access online services. Posted the Japanese Nintendo account: "We have confirmed the existence of unauthorised services that replace functions such as online play for the Wii U, which ended service on April 9, 2024. Please refrain from using such services as they may pose unexpected security risks."

After Nintendo shut down Wii U and 3DS online servers last April, players brought the functionality back online just a day later thanks to fan collective Pretendo.