China is treating North Korea like a colony. China lets the local thugs (the “workers party” of the Kim family) run the place while China supplies enough food to prevent mass starvation and enough fuel to keep the lights on in the capital. China pays for this with a network of mining contracts in North Korea. For the last five years China has built and operated these mines, on very attractive (to China) terms. The North Korean government can’t complain about the arrangement because China is the only ally North Korea has (unless you want to count Cuba, Venezuela and Burma, and the latter has been unreliable of late). China props up the North Korean tyranny because that’s cheaper than letting the North Korean government collapse and taking over and running North Korea as an extension of northeast China. It would also be very expensive. That could run into a nasty outbreak of Korean nationalism, and a call for the other Chinese nightmare; a united Korea. That would probably be on South Korean terms and China does not want a prosperous democracy on its borders. So turning North Korea into an exploitable prison camp, run by some of the prisoners, is a suitable solution. The only downside is that the North Korea officials often do outrageous things (like make and break deals with South Korea, Japan and the United States). The current outrage, over North Korean efforts to renege on a recent aid deal and launch a space satellite, annoys China, who really can’t do anything since they have allowed the inmates to run the asylum known as North Korea.