LITN is correct, Asian countries are super hardcore when it comes to citizenship like allowing to have only just one country compared to America and Western Europe which normally allows two. I've read stories where Japanese-American ex-pats wanted to become Japanese citizens since they loved Japan and had to relinquish USA citizenship to become Japanese citizens to potentially stay in the country. Now though, majority of people get marriage visa's and are able to stay in the country that way. So in Son's case, he could potentially get rid of his Korean citizenship, gain a UK passport which will get rid of his military duty, and then marry a Korean women to stay in the country after he's done with football. Of course there could be anti-trust laws which prevent this.
Does Son's military assignment have to be done in years? What I mean is that Finland has required military participation and all NHL players have to do, which majority do in the offseason/summer months. I think Korea is much more strict than Finland is, but maybe he can split them up into semesters instead of years'.
