These two countries have a long history with each other and one that I'm not even going to try to recount here, however if you're ever hanging out with a Korean or happen to be in Korea, make sure you're careful what you say about their neighbors.
Below is a map of Korea you will never see in the ROK. Do you know why? (Well, other than the Romanised spelling...)
|You will never see a map like this in the ROK.|
I used this exact map during a presentation I made to a class of 6th graders in my first month here, and I had students falling out of their seats and shouting at me. Notice the name of the sea between Korea and Japan? That's right, "Sea of Japan". The Koreans don't think too highly of this name and instead refer to it as the "East Sea".
The Japanese invaded South Korea twice in the last 5-600 years, and the last invasion was not too long ago. Japan colonized Korea during the first half of the last century, so the wounds are still pretty fresh, despite having another war (the Korean war) and invasion from their own northern half since then. If you can't imagine well the passion they feel against their former colonizers, I had a Korean friend over coffee once, liken them to the Nazis.
Another point of contention at the moment is over a little tiny island that lies smack dab in between the two countries. Dok-do as it's referred to by the Koreans, and Takeshima by the Japanese, is nothing more than two tiny little mounds of land in the sea, with no inhabitants, nothing actually. But it is a matter of huge pride to the Koreans that this land remains theirs. The island is so small, it can barely be seen on the map, in fact, if you have a look again at the map above, Dok-do isn't even on it. But it is none-the-less a big deal. Don't go messing with Dok-do.
|(Above) Not my picture, but I have seen protestors with similar signs marching in Seoul. (Below) A picture of Dok-do: what all the fuss is about .|