China & North Korea

Following the detonation of a thermonuclear device and test of an intercontinental missile, where does China really stand on the vexed question of N Korea. Since the end of the Korean war I believe they have enjoyed having a buffer zone between themselves and South Korea, an ally of the US. They maintained the North, traded with it, armed it and maintained its Communist regime despite itself turning towards a a more capitalist outlook. As the Chinese economy grew, they realised the benefits of trade with the US and left North Korea behind but not before ensuring its survival as an independant state. To do this the Chinese recognised that the North needed a nuclear deterrent as insurance against a US backed South Korean incursion and attempt at unification. So now they have it and China says and ostensibly acts within UN directives in order to maintain trade with the US whilst maintaining the buffer zone in the Korean Peninsular-a win/win situation for China. Now that this is a reality, the rhetoric will die down and the world will have to accept that there is another nuclear power. Gradually the Chinese will covertly soften the stance on trade embargoes with North Korea ensuring that the Country prospers under Kim Jong-un a guarantee of peace and security on its southern border.
The US will quietly acquiesce to this recognising that there is no other realistic option. Japan will soften their stance once the North Koreans promise not to overfly Japanese territories; they, like the South Koreans have no other options either. As they have done for nearly seventy years nuclear weapons will continue to act a deterrent.