I was actually trying to figure this out with friends. In China you need to get married where you hukou is registered, but neither of them are from Xiamen. It's quite hard to change your hukou, though with his fame I'm sure nowadays it would be easy. But like you said, he wouldn't qualify for a xiamen hukou these days. (it would have to be beijing). But he lived and trained in Xiamen for years before he joined the national team, so he probably has houses here and and residence permit (户籍）so that's how he was able to get married in Xiamen We are all feeling a lot of Xiamen pride here because of their marriage. It's a great city, one of the top ones in China and probably THE best city for badminton in the entire country of china (based on the level of the amateur players as a Xiamen team or Xiamen players tend to win most major nationwide competitions). So we are quite happy he was able to get married here. Although no one knew he had such a strong legal connection to the city.