Now that we have our first North Korea question I decided to check if we previously used korea or south-korea.
So right now we have south-korea and korea redirects to it!
I find this a bit wrong, no matter the fact that we'll have a lot more questions about South than North, that the North is bad, or that lots of people say "Korea" when they mean "South Korea" - just as I do.
But we're an expert site so we shouldn't really make the assumption and just offer south-korea and north-korea.
The tag completion feature will show the two options as people start typing "Korea". If lots of people with the tag creation privilege started to re-create the plain "korea" tag I believe there's a tag blacklist feature used on some other SE sites.