Nintendo's aggressive stance against emulation is well-documented. Recent examples include the $2.4 million settlement with Yuzu emulator developers in March 2024, the cessation of Ryujinx development in October 2024 following Nintendo contact, and the advice given to Dolphin developers regarding a Steam release in 2023 due to Nintendo's legal pressure. The high-profile 2023 case against Gary Bowser, resulting in a $14.5 million debt to Nintendo for his involvement in distributing devices that bypassed Nintendo Switch anti-piracy measures, further highlights this commitment.
Now, a Nintendo patent lawyer, Koji Nishiura, has shed light on the company's strategy. Speaking at Tokyo eSports Festa 2025, Nishiura 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 laws, particularly under Japan's Unfair Competition Prevention Act (UCPA). This act, however, is limited to Japan, making international legal action more challenging.
Nishiura used the Nintendo DS "R4" card as an example. This device allowed users to bypass security and run pirated games. Following legal action by Nintendo and other software manufacturers, the R4 was effectively outlawed in Japan in 2009. He also highlighted the illegality of "reach apps"—third-party tools facilitating pirated software downloads within emulators or other software, citing examples like the 3DS's "Freeshop" and the Switch's "Tinfoil."
Nintendo's lawsuit against Yuzu cited one million pirated copies of The Legend of Zelda: Tears of the Kingdom, emphasizing the financial gains allegedly made by Yuzu developers through Patreon subscriptions offering early access and special features.