By Ian Wood
Released in early access on January 19, 2024, Palworld is an open-world survival game often described as “Pokémon with guns.” Players capture creatures called “Pals” and use them for combat, traversal, and base building.
After a brief honeymoon period following launch, Nintendo and The Pokémon Company filed a patent infringement lawsuit against Pocketpair, the Tokyo based developer behind Palworld, in September 2024. The companies alleged that Palworld infringed patents covering gameplay mechanics similar to those used in the Pokémon series. Nintendo and The Pokémon Company sought both an injunction to halt the alleged infringement and compensation for damages.
One patent at the centre of the dispute carries the title “Storage medium, information processing apparatus, and game processing method.” Nintendo filed the patent shortly after Palworld entered early access in January 2024. It covers an in-game mechanic in which a player summons a secondary character to assist in battle. Legal commentators noted the timing of the filing, suggesting it may have been submitted specifically to strengthen Nintendo’s anticipated litigation against Pocketpair.
In October 2025, Japan’s Patent Office (JPO) rejected three of Nintendo’s Japanese patents included in the lawsuit following the submission of prior art by a third party. Among them was a so called “monster capture” patent that sat at the heart of Nintendo’s case. The prior art references cited by the JPO pre-dated Nintendo’s claimed priority date of December 2021 and included Capcom’s Monster Hunter 4, Pocketpair’s earlier title Craftopia and the browser game Kantai Collection. The breadth of those references raised questions about the originality of the mechanics Nintendo sought to protect.
Nintendo also faced setbacks in the United States. The United States Patent and Trademark Office (USPTO) rejected all claims under review, citing a combination of prior art drawn from previously published patent applications. The office identified four key references: Nintendo’s Taura patent, Konami’s Yabe patent, Bandai Namco’s Shimomoto patent and Nintendo’s Motokura patent.
Notably, one of the key invalidating references came from Nintendo itself. The Taura patent formed part of every invalidity theory identified in the USPTO’s preliminary decision. It describes a system in which a secondary character appears and is automatically controlled except during attacks against enemies.
The USPTO also cited Konami’s Yabe patent, which covers companion characters operating either in response to player inputs or through automated behaviour routines. Nintendo’s Motokura patent similarly describes a system in which a secondary character performs actions automatically at a player designated location within a virtual environment. The Shimomoto patent from Bandai Namco describes a mechanic where a stored sub-character appears automatically once specific gameplay conditions are met.
In November 2024, Pocketpair removed the ability to summon Pals by throwing Pal Spheres, one of the mechanics most visually reminiscent of Pokémon’s Poké Ball system. While the company did not publicly connect the change to the litigation, the timing led many observers to interpret it as an attempt to distance Palworld from the disputed mechanics.
However, in the ongoing litigation case happening in Japan, Pocketpair has argued that publicly distributed game modifications, commonly known as “mods,” can qualify as prior art predating the patents at issue. One example cited by Pocketpair was “Pocket Souls,” a fan made mod that combines Pokémon mechanics with the action role playing game Dark Souls 3. The argument carries potential legal weight under U.S. law. Under 35 U.S.C. § 102(a), material may qualify as prior art if it was patented, described in a printed publication, in public use, on sale or otherwise publicly available before the effective filing date of the claimed invention. Mods that are widely distributed and in some cases commercially sold could satisfy multiple prongs of that standard. Given the extensive history of publicly available mods across gaming genres, their possible role as prior art may become increasingly significant as the case develops.
Despite the setbacks Nintendo has faced before both the JPO and the USPTO, the broader litigation in Japan has continued to move slowly, with no major substantive rulings emerging in recent months. Both sides have largely declined to comment publicly on the proceedings in detail.
With patent offices in two countries now raising serious doubts about the validity of Nintendo’s key claims, and with the scope of potential prior art continuing to expand, the dispute remains one of the most closely watched legal battles in the video game industry. Its outcome could shape how courts and patent office’s treat gameplay mechanics as protectable intellectual property, potentially influencing future disputes far beyond Palworld and Pokémon.
Ian is a legal professional with degrees in law and Computer Science. He currently works as a junior consultant at Agile Owl, supporting indie businesses and creative professionals.
