At 4:30 a.m. on a May morning in Hong Kong, Joseph Tsai gathered with three other executives of Alibaba Group Holding Ltd. With the U.S. While Chairman Jack Ma is the visionary founder of Alibaba, Tsai, the vice chairman, is the guy who stays up until 4:30 a.m. to execute that vision. “Alibaba wouldn’t be where it is today without Joe Tsai,” said Porter Erisman, who worked in marketing and communications at Alibaba in the early days and just released a documentary on the company’s beginnings.