Lol it's not a rocket science to tell why. The main reason is LYD needs a younger partner not necessarily Choi. Why I said Choi is, LYD plays with him in national tournament and iirc they won this or last year. I am not saying Choi is the best partner of LYD but with a younger partner like Choi, he may atleast win the first round in intl tournaments. Play hard. Train harder.