What kind of relationship does China have with North Korea?
On the surface, these two cold war brothers-in-arms have an awful lot in common, but six nuclear tests have sorely tested Beijing's patience with the country it has previously described as being "as close as lips and teeth". It seems bizarre how far North Korea is prepared to push China. Beijing is North Korea's only significant ally, an ideological comrade that fought shoulder-to-shoulder against the Americans in the Korean War (1950-53). Since the collapse of the Soviet Union, China has stepped in as North Korea's main benefactor, supplying food and fuel aid for the North, and trying to occupy a similar role to the North Koreans that the US occupies with the South Koreans.
China appears lukewarm on United Nations sanctions, although it has backed recent rounds. Why is this?
China is nothing if not pragmatic, and its reluctance to back sanctions is informed by its worries about their impact on a highly unstable neighbour. Beijing fears a mass influx of refugees from North Korea if the fuel and food runs out. Also, the Kim government would most likely be replaced with a US-backed administration, which China does not want on its borders.
The Chinese are also sceptical about the effect of sanctions. They have watched the repeated failure of economic sanctions to make any difference, whether in contemporary Russia or Fidel Castro's Cuba. It's important to remember that North Korea appears better able to tolerate hardship than most. In the famine that hit the country in the 1990s, between one million and 3.5 million of the country's 22 million people are thought to have died, and the government did not bat an eyelid.
What is driving the North Koreans towards these constant provocations?
For North Korea, the nuclear armaments programme has been driven by the belief that the US and South Korea want to destroy it and finish the job started during the Korean War, which ended with a truce, not a peace treaty.
North Korea has an army of 1.2 million troops, and it is reportedly struggling to feed them. A nuclear deterrent is a far cheaper, and more effective, way of fighting what it sees as US aggression in the region.
So, does China really have much influence over its ally?
Although Donald Trump firmly believes that Beijing has huge influence over North Korea, this is not necessarily true, despite appearances. On the surface, the two communist neighbours and wartime allies should be working in concert. Zhang Dejiang, a key figure on the ruling Politburo Standing Committee, studied at the Kim Il-sung University in Pyongyang in the 1970s. China chaired six-party talks featuring both Koreas, the US, Russia and Japan, but to no avail.
China dislikes the instability in the region but North Korea has treated it just as dismissively as all the other players in the nuclear stand-off on the Korean Peninsula. For too many years, China has given North Korea the benefit of the doubt. If China did have leverage with North Korea, that particular horse appears to have bolted with its latest nuclear test.
Is China right to say that dialogue is the only way to resolve the crisis?
Probably. But constantly repeating that only dialogue will resolve the nuclear stand-off is no longer enough. China now has the opportunity to step up and actually put pressure on the North to get to the negotiating table. It’s also a tactical necessity.