Under President Xi Jinping, China is pioneering a new form of governance by surveillance. In the first of a two-part series, we look at how China tested that system by targeting one minority group. Guest: Paul Mozur, a technology reporter for The New York Times based in Shanghai. For more information on today's episode, visit nytimes.com/thedaily. Background reading: Chinese authorities are expanding an extensive surveillance net by using a vast, secret system of facial recognition technology to control the Uighurs, a largely Muslim minority.Technology built for China's surveillance system is now being applied — and sometimes abused — by other governments.