Context: Last fall, Nintendo and The Pokémon Company sued Palworld maker Pocketpair over three Japanese patents (note that links like the one to the left of this parenthesis take you to our IP Lingo dictionary explaining such terms). Earlier this year, we launched an “explain it to me like I’m five” series covering the dispute (January 23, 2025 games fray article). We sent a Japanese attorney to a Tokyo courthouse to take a look at Pocketpair’s defenses, and reported on then three months ago (April 18, 2025 games fray article). Subsequently, we explained Pocketpair’s “moving target” strategy that involves changes to gameplay mechanics so as to work around Nintendo’s patents, making it impossible so far for Nintendo to find a basis for a good-faith U.S. patent assertion (May 10, 2025 games fray article). Nintendo would apparently like to sue in the U.S. as well, but so far it can’t.
What’s new:
- In a clear sign that Pocketpair’s defenses have also made a strong impression on Nintendo, the latter ran to the Japan Patent Office (JPO) in the spring and requested a modification of one of its three patents-in-suit. The JPO has granted and, finally, published that request. We will discuss the claim amendments below (link).
- Furthermore we’ll take a look at Nintendo’s latest tactics in the U.S., where it has also presented new patent claims (link).
Direct impact:
- Litigants don’t change a patent in the middle of an infringement case unless they feel the patent is at a fairly high risk of being deemed invalid in its original form. That doesn’t mean they always lose: sometimes it is possible to thread the needle and amend a patent in a way that enables it to survive the invalidity contentions, yet allows the patent holder to succeed in terms of establishing an infringement by the accused product or service. However, the way Nintendo has worded its new claims here is — to put it bluntly — weird, and doesn’t appear likely to solve Nintendo’s problems in this dispute.
- Even with Nintendo’s new maneuvering in the U.S., it remains doubtful that there can be a promising U.S. patent infringement lawsuit against Pocketpair. The situation reminds of the old Tom and Jerry (Wikipedia link) cartoons where the cat tries to catch the mouse, but the latter is just too agile and resourceful.
Wider ramifications: Nintendo’s patent lawfare against Pocketpair may partly be intended to discourage other companies, particularly indies, from making games that bear some abstract resemblance to Pokémon. However, at least Kingsglory, a Funplus label, does not seem to care and is going ahead with its Aniimo game regardless.
1. Nintendo’s modified patent claims on the smooth switching of riding objects: “even when” is awkward patent claim language
For a recap, Nintendo is asserting three Japanese patents against Pocketpair. Two of them relate to the collection of characters (February 6, 2025 games fray article), and the third is about the smooth switching of riding objects, such as switching from horseback riding to flying on the back of a bird-like character. We’re now talking about the third, not the other two.
We reported earlier this year that a Japanese patent attorney does not believe that Pocketpair ever implemented that switching mechanism (January 26, 2025 games fray article). Also, the gliding functionality that Palworld had when it launched, and which was recently removed because Pocketpair wants Nintendo’s patent assertions to go nowhere, was already demoed by Pocketpair in June 2021 (May 11, 2025 games fray article), six months prior to the original Nintendo patent application based on which Nintendo then filed for new patents well after Palworld’s launch (January 23, 2025 games fray article).
As we explained in the article we just linked to, what matters legally is not the filing date of a patent application, but its priority date: you can claim back priority to an older application if you file a new one that is derived from the same substance. However, Pocketpair has presented plenty of prior art: it predates not just the patent applications but also their relevant priority dates.
This concept of being able to derive something from an older (in this case almost four-year-old) patent application while benefiting from the older priority date is very relevant now that we’re talking about Nintendo having modified its smooth switching patent (number: JP7528390; JP stands for Japan). The same principle applies to any modifications now: Nintendo can use the original patent application as a pool, like a primordial soup. That’s fair game. But it is limited to that because it would otherwise not be entitled to that original priority date.
So, what did Nintendo do then? Here’s a PDF in which we saved an English machine translation provided by the JPO itself:
Here’s the decision that finds that those claims do not introduce any new technical matter, meaning that (to use our metaphor from further above) the modified claims are still based on what is found in the 2021 primordial patent soup:
When we looked at the new claims, we were neither convinced that Palworld (at least in its current form) infringes them nor that they are capable of overcoming Pocketpair’s strong invalidity defenses (April 18, 2025 games fray article). But what really stood out is the way the claims are worded. Here’s just one passage (as the claims as a whole would be too long and, frankly, cumbersome; you can find them in the first PDF anyway):
. . . and even when [emphasis added] any boarding character other than the aerial boarding character capable of moving in the air is the currently selected boarding character and a first operation input is given when the player character is in the air, the computer causes the aerial boarding character to appear in the virtual space, and causes the player character to board the aerial boarding character instead of the currently selected boarding character from among the boarding characters; . . .
I’ve been following patent litigation for 15 years (for the better part of that period as a consultant) and have seen many claims that were amended, but I’ve never seen “even when” or “even if” in a patent claim. It’s bizarre.
Florian Mueller
Now, patent claims are not like everyday language. But the above type of wording is extremely contorted, trying to complicate things for the purpose of putting up a huge smokescreen, and above all, “even when” is normally not found in patent claims.
Conditions (if/when) are normal in patent claims. But “even” is a word that has no place in patent claims. It is too emphatic and subjective. Patent claims have the purpose of describing how certain means are used to achieve a particular end, and to to do so in a way that at least those who know a thing or two about patent law will have an idea of what the patent covers. The name of the game is the claim. The claims (each patent can have, and usually does have, multiple claims) define the scope.
It is almost a Hail Mary: a desperate attempt to win by doing something odd. However, Presiding Judge Motoyuki Nakashima is very experienced in patent law. He can’t be gaslighted by strange claim language.
2. New U.S. claims may still not enable Nintendo to bring a reasonably strong U.S. patent lawsuit against Pocketpair
By changing its gameplay mechanics (May 10, 2025 games fray article), Pocketpair has apparently reacted to Nintendo’s patent filing activities in the U.S., where it is not suing so far and may never have an opportunity to gain anything from litigation.
Nintendo doesn’t give up easily. Even after a setback (February 8, 2025 games fray article), it found a way to keep a patent application alive and received a notice of allowance in the spring (April 3, 2025 games fray article). If Pocketpair hadn’t made some further changes to Palworld, that notice of allowance would have resulted in a patent Nintendo would probably have argued to be infringed by Palworld.
Instead of taking what the patent examiner was finally willing to grant, which just required Nintendo to file a free within three months, the company however decided to wait until the end of that term and present a new set of proposed claims:
It is a fairly common tactic to ensure that least one application from a given patent family is still being examined, meaning that one can still try to react to changes (such as new Palworld releases) with new claims that could then be optimized to sue over a given product. Nintendo can’t be blamed for that.
The claim language presented in the U.S. is not as odd as the one in Japan, but wordings like “selected based on the selection operation” are what linguistis call tautological.
At this point we can’t see how those new claims would read on Palworld in its current form (“to read on” in patent law means that a patent claim covers something, meaning there is an infringement argument). We just wanted to share the above document from the USPTO record as an update. It looks like a cat-and-mouse game, which is why we mentioned the decades-old Tom and Jerry cartoon further above.
We will continue to keep an eye on this dispute because we know that many gamers are interested in it. We respect Nintendo’s true innovations, which are technical in nature and not game rule patents. It’s just hard to make sense of what Nintendo is doing in the Palworld context, and maybe Nintendo itself is slowly but surely getting to the point where it can’t make sense of it anymore.