Baise, or Bose, is the westernmost prefecture-level city of Guangxi, China bordering Vietnam as well as the provinces of Guizhou and Yunnan. …Baise, or Bose, is the westernmost prefecture-level city of Guangxi, China bordering Vietnam as well as the provinces of Guizhou and Yunnan. The city has a population of 4.3 million, of which 1.4 million live in the urban area.