Episode 38

The *Palworld* lawsuit and related patent applications have been a topic of discussion.
This is a patent infringement lawsuit filed by Nintendo Co., Ltd. and The Pokémon Company against Pocketpair, Inc., the developer and distributor of the game software *Palworld*.
When it comes to rights infringement regarding game software, both copyright infringement and patent infringement are potential issues.
Copyright infringement lawsuits require proving both similarity and reliance, which sets a high hurdle. For instance, GREE, Inc. sued DeNA Co., Ltd. and others, claiming that the mobile internet game *Tsuri-ge Town 2* infringed on the plaintiff's copyright; while the court of first instance granted an injunction and partial damages, the appellate court found no copyright infringement and overturned the initial ruling.
In patent infringement lawsuits, the claim is typically that the game's algorithms infringe upon the plaintiff's patent rights. Plaintiffs can gain a strategic advantage by splitting off and continuing a portion of the original patent application, and subsequently filing a divisional application tailored to the allegedly infringing product.
Defendants can avoid infringement by altering the design of the accused product. In such cases, the plaintiff might argue the "doctrine of equivalents" or file a new divisional application aligned with the redesigned product.
Defendants may also raise a defense based on grounds for invalidation (Article 104-3 of the Patent Act).
Patent infringement litigation is akin to mixed martial arts. Even when you believe you are gaining the upper hand, a counter-move by the opponent can instantly turn the tables.
Courts often seek to resolve cases through settlement rather than a formal judgment (Article 89 of the Code of Civil Procedure). Settling the case allows the court to avoid the burden of drafting a judgment. While court records are generally open to the public (Article 91, Paragraph 1 of the Act), the portions concerning settlement terms are kept confidential (Article 91, Paragraph 2, Sentence 2), allowing the parties to avoid public disclosure of the settlement details.
In the *Palworld* lawsuit, a divisional application (Patent Application No. 2026-19762)—derived from the patent forming the basis of the claim (priority date of the original application: December 2021)—has drawn attention after receiving a notice of refusal citing a video of game software submitted via a third-party information submission. The cited video dates back to 2013.
It is presumed that the plaintiff filed the divisional application in hopes of securing more favorable settlement terms should the court recommend a settlement; however, by receiving a refusal based on a video published prior to the priority date of the original patent, they effectively provided the opposing party with grounds to argue for the patent's invalidity. In short, they stirred up a hornet's nest.