USPTO Rejects All 26 Claims of Nintendo’s ‘Summon and Fight’ Patent, Sending Ripples Through Palworld Dispute

The United States Patent and Trademark Office (USPTO) issued a non-final office action in early April 2026 rejecting all 26 claims of a Nintendo patent directed to a method of summoning a sub-character to engage in combat in one of two modes. The rejection followed a November 2025 order by USPTO Director John A. Squires directing ex parte reexamination of the patent, an exercise of rare directorial authority: of approximately 15,000 reexamination requests filed since 1981, the director has ordered reexamination in only 175 instances.

The examiner rejected all claims on obviousness grounds, citing as primary prior art a Konami patent filed in 2002 and a separate Nintendo patent application from 2019. The examiner concluded that a person of ordinary skill in the art would have been motivated to combine these references in a manner that renders each of the asserted claims obvious. As a non-final rejection, Nintendo has two months from the mailing date to respond with arguments, amendments, or both.

The patent at issue is a U.S. application separate from the three Japanese patents Nintendo cited in its September 2024 lawsuit against Pocketpair, Inc. before the Tokyo District Court. The USPTO’s non-final rejection therefore does not directly affect the claims at issue in the Japanese litigation. If the rejection becomes final and the patent is ultimately cancelled, however, the case would illustrate the difficulty of securing broad exclusive rights over fundamental gameplay mechanics such as creature summoning and combat.

Nintendo retains procedural options. Should the examiner issue a final rejection, Nintendo may appeal to the Patent Trial and Appeal Board (PTAB) and, if necessary, to the U.S. Court of Appeals for the Federal Circuit. Alternatively, Nintendo may narrow its claims through amendment, potentially preserving some portion of the patent. A non-final rejection at the reexamination stage is not the end of the road.

Parallel developments in Japan add further context. Multiple media outlets reported that the Japan Patent Office (JPO) rejected more than 20 Nintendo patent applications relating to monster-capturing mechanics, citing prior art including several major titles in the action-survival and role-playing game genres as well as Pocketpair’s own earlier game Craftopia. Those JPO actions concern pending applications, not the granted patents asserted in the Tokyo lawsuit, and do not directly invalidate the patents Nintendo is enforcing.

The Tokyo District Court case, presided over by Judge Motoyuki Nakashima, remains ongoing and is expected to continue through 2026. Nintendo and Pocketpair have not issued public statements regarding the USPTO office action. The outcome of the reexamination proceeding will be watched closely by game developers and IP practitioners assessing the outer boundaries of patent protection for interactive gameplay systems.