Japan Patent Office Rejects 20 Nintendo Patents in Palworld Dispute

More than 20 Nintendo patent applications tied to monster-catching mechanics were rejected by Japan's patent office, a fresh setback in a dispute that already has lawyers, designers and rival studios watching how far game mechanics can be protected. The refusals do not end the case, but they put pressure on Nintendo’s patent strategy at the exact point where the company is trying to define the legal boundary around one of its most recognizable design spaces.

The most closely watched filing, Japanese application no. 2024-031879, was rejected on a non-final basis for lacking inventive step, after a third party submitted prior art. That matters because Nintendo can still respond or amend the application, but the rejection gives Pocketpair and other observers a public sign that the Japan Patent Office is not accepting the broadest version of the claim as originally framed.

The broader Palworld fight began in September 2024, when Nintendo and The Pokémon Company sued Pocketpair in Japan over Palworld, the open-world survival game that launched in January 2024. The case centers on three Japanese patents granted by the Japan Patent Office, including two linked to monster capture and release and one tied to riding characters. For Nintendo, the issue is not only about one game. It goes to the legal durability of systems that have helped define Pokémon and similar creature-collection games for decades.

Earlier reporting on the rejection pointed to older games that examiners treated as prior art, including ARK: Survival Evolved, Monster Hunter 4, Craftopia, Kantai Collection and Pokémon GO, all predating Nintendo’s December 2021 priority date. That list is a warning sign for any legal team trying to draw a clean line between a proprietary invention and a familiar genre convention. In practice, the argument becomes harder when the mechanics at issue resemble systems already visible across the industry.

The stakes are larger than one patent file. A public rejection can weaken leverage in negotiations, invite closer scrutiny from outside counsel, and encourage other companies to look more aggressively at Nintendo’s claims. It also forces a sharper internal question for creative and production teams: where does an idea stop being a mechanic and start becoming a defensible invention? For developers inside Nintendo, that distinction affects how features are documented, reviewed and defended before they reach market.

The pressure is not limited to Japan. In April 2026, the United States Patent and Trademark Office issued a non-final rejection of Nintendo’s separate “summon character and let it fight” patent, adding another signal that the company’s patent posture is facing resistance in more than one jurisdiction. Nintendo still has strong franchises and a powerful market position, but this dispute shows that patent law may be a weaker shield than the company would like when the fight is over mechanics that the industry treats as common language.