Well, Monopoly and Star Trek are not really Japanese things, yanno? Like, if some one didn't know what those were in the US or Europe, then maybe.
I mean, did you stop at just asking about those two things or did you keep going to see if they knew anything of fantasy or whatever fictional stuff or other board games. Because other board games do exist than Monopoly
*ahem* Anyways, welcome to the board!
Heh, now I'm imagining some Japanese people speaking English with Australian accents, sorry xD