Maybe they had some type of agreement with IBM. IBM made the "Gekko" processor for the Gamecube, after all.
You can trademark three letter abreviations in a specific type of field (ie computers) IBMs RPG is a database programming language that was made in 1959 and is still used today. Bandai registered RPG back in the late 70s I seem to have read somewhere. Whether these would hold up in court is a different matter, although Japanese courts are different and english words can be happily trademarked as long as you can prove the usage.A lot of words are now so much in the public domain that it could be hard to claim trademark infringement, hoover for example is in the English dictionary with a small h, so Hoover the company can not sue anyone for using hoover in a press release (i.e "our vacuum cleaner hoovers better then any other vacuum on the martket"), although they could if they called their product a hoover. In europe anyway there is a big difference between computer game, video game and board game, so trademarking one does not automaticaly give you use on the other two. Although it does lean more in your favour. I remember some lawyers sending the company I work for a letter claiming trademark infingment and demanding a payment for use. Although we had the highly paid Corporation of London lawyers send them a reply ripping them claim apart and even threathening to countersue them for falsely using a trademark.
How the hell can you trademark an acronym that has more than one potential use? .... what about Rocket Propelled Grenade?
In the US, you can trademark something in a particular field, like "RPG" relating to computers. I just wonder if there could've been a case for Super Mario RPG using the acronym in the same field as IBM's RPG?
You guys are funny and so are the documents. US trademark law requires one big thing: you sue anyone and everyone even remotely potentially infringing on your trademark or else you might lose it due to perceived complacency with someone infringing on it. That is why the document forbids it, just in case. However, it is also extremely clear that trademarks are for trade so if ASSEMbler were to trademark ASSEMbler Games to do business with in terms of video games and I move to use ASSEMBLER as a shop who builds dishwashers (people do stuff like this all the time without even realizing there was someone already using the name) the suit brought forth would likely be dismissed as dishwasher assembly and video games are in the same realm of trade. Clearly a RPG in video game terms is not the same thing as what IBM was using it for, SEGA was trying to avoid a lawsuit. Now I can't speak for Japanese or European trademark laws but that is the jist of American as I understand them. The former is really stupid and you see Apple slinging their lawyer hammer around often. May I refer you to Apple the music label Vs Apple Computer?
I'm not that familiar with trademark laws, but come on, it's not like things lawyers do have anything to with logic. BTW, it was Apple Corps suing Apple Computers, not the other way around (there's been several lawsuits, many of them successful, by Apple Corps, and it all started way before the current "hipster darling" era of Apple).