The mix-up over the two Chens is one of the more extreme cases of "repeat identity" in China, caused when an administrative error gives citizens an identity card number that's already been issued. The Ministry of Public Security has been eradicating such cases as part of a campaign which ended in June, and Xinhua News Agency says there are now fewer than 10 repeat identity card numbers, down from some 1.1 million in 2009.