Liu Ding, a kind of orange peculiar to Taiwan Province, is orange when it matures. As for the black Liu Ding, I think you mean Taoji's album or song. If it is, then in the album, Liu Ding represents Taiwan Province where Taoji is, while the black Liu Ding represents Taiwan Province, which is deteriorated and degraded in Taoji's eyes. In addition, black can represent rock and roll, a spirit of critical resistance. I appreciate his album very much!