"China has told South Korea that it will not allow the unification of Korea under a
democratic government. North Korea will remain under Chinese "influence." If
worse comes to worse, China will send in troops to set up a North Korean
government that will faithfully follow orders from China. In an effort to dampen
some of the anger in South Korea (the United States, Japan and so on), China
would maintain North Korea as a separate entity (and not a new province of
China). China wants no misunderstanding about who "owns" North Korea."
See:
http://www.strategypage.com/qnd/kore.../20120708.aspx