Nintendo's aggressive stance against emulation is well-documented. Recent examples include the $2.4 million settlement with Yuzu developers in March 2024, the cessation of Ryujinx development in October 2024 following Nintendo contact, and legal advice preventing a full Steam release for the Gamecube/Wii emulator Dolphin in 2023 due to Nintendo's intervention. The $14.5 million judgment against Gary Bowser in 2023, for reselling devices that bypassed Nintendo Switch anti-piracy measures, further highlights this commitment.
A patent lawyer representing Nintendo recently shed light on the company's strategy at Tokyo eSports Festa 2025. Koji Nishiura, Assistant Manager of Nintendo's Intellectual Property Division, clarified that while emulators aren't inherently illegal, their use can become illegal depending on how they function. Specifically, emulators that copy game programs or disable console security measures may infringe on copyright. This is largely based on Japan's Unfair Competition Prevention Act (UCPA), limiting Nintendo's overseas legal reach.
The Nintendo DS "R4" card, which allowed users to play backup or pirated games, served as a case study. Nintendo's successful 2009 lawsuit against R4 manufacturers and resellers, citing UCPA violations, effectively outlawed its sales in Japan. Nishiura also emphasized that tools facilitating pirated software downloads within emulators, such as the 3DS "Freeshop" or the Switch's "Tinfoil," could also constitute copyright infringement under Japanese law.
Nintendo's lawsuit against Yuzu cited one million pirated copies of The Legend of Zelda: Tears of the Kingdom, highlighting the financial incentive behind their legal actions, particularly referencing Yuzu's Patreon revenue generated from providing early access and exclusive features.