China is the most populous country in the world and the most overseas populous country in the world. Since the modern times, Chinese people have been constantly moving abroad, and there have been two major immigration frenzy. In the 1840s, after the Opium War, the first wave of immigration worsened as the Western powers invaded China and plundered Chinese workers (華工). Then, in the 1980s, China implemented a reform and open - door policy to "run out, get out and get in." There was a big wave of immigration once again. (Usually called the second immigrant wave as a new immigrant).