Comment by agubelu

(Patent attorney) The patents in question are continuation patents. Essentially, Nintendo filed a patent application before Palworld was released that disclosed the mechanics Nintendo is patenting now. That original application only included claims covering a subset of the mechanics described in the application. They can continue filing additional applications with new claims that cover the mechanics described entirely in the original application and get the benefit of having the priority date of the original application so long as they meet certain requirements about the timing.

Original application: I invented A, B, C, D, E, and F and want A protected; here’s some $. Follow-up application 1: I want invention B protected, here’s some more $. Follow up application 2: I want C protected, here’s some more $.

Part of the idea behind it is that you don’t have to waste money protecting parts of what you invented that don’t pan out (additional claims cost additional money beyond a certain number of claims). It’s not particularly fair, since you can watch what a competitor does (as Nintendo has done here), and essentially backdate a patent as though you had filed for it before the competitor did their thing.

I'm not a lawyer, but I have 20+ patents. There are some pathological situations where company A launches a product after Company B has applied for a patent, but before the patent is issued. Also, there are rules for prior art, related to the timing of when the prior art became known (through publication, release of a product, etc). It can get even more screwy when an inventor files for a patent in more than one country.

Company A might have known about the application, but was confident that it would not be issued or defensible.

Things like "obviousness" and "prior art" can be hard to judge unless you're a patent lawyer... or a judge.

It could be a continuation application that claims priority to an earlier application.