Is there any good reason why china won't agree with the US to obliterate North Korea?

Is the US military the motivation behind why China supports North Korea?

The more I think about this scenario, the more it seems that US specially want to continue the tension developing in world and chaos after North Koreas' recent missiles tests one of them is flow over Japan.

AmeliaFrancis International Politics 8/31/2017 1:17:37 AM 129 Times