Ordinary Chinese and rank and file PLA troops are not crazy about N. Korea for some time.
A few years ago, Chicom had a contingency plan in case everything goes south.
It could include annexation of N. Korea as a whole or its part.
What do you think that U.S. and China are haggling about behind closed doors? The price for China to let Kim Jong-il regime go down.
Makes sense.
And as you said -- Red China and the U.S. are not on the same side.
I think the Chinese deal with the United states is essentially complete. Probably just last minute adjustments are left. Chinese guarantees to Japan are probably unsettled. The Japanese Abe government is an indication this is so.
The Russian - Chinese deal appears complete also. The United States government is a bit miffed at being left out of that one. A major Russian - Japanese deal is in the works with negotiation now at the "who gets what and who pays for it?" stage.
The politics of East Asia are most interesting.
Here's an idea...
China can have North Korea, providing they give up their claims on Taiwan.