[Skip to comments.](#comment) Posted on 08/15/2021 9:21:31 AM PDT by [E. Pluribus Unum](/~epluribusunum/) Nobody knew until last month that Joseph Chung-Hsin Tsai — better known as Joe Tsai — was the “mystery buyer” who dropped $157 million this spring on two massive condos at 220 Central Park South, the most expensive apartment building in the country. So far, keeping a relatively low profile and understanding international office politics has worked out well for Tsai, said to be worth at least $12 billion. The 57-year-old is the co-founder of Alibaba (China’s version of Amazon), the owner of the Brooklyn Nets and…