North Korea’s third nuclear test represents a challenge to all countries interested in the future of the pariah state.

For South Korea, it is a final rebuke against the hardline policies of outgoing president Lee Myung-bak and a reminder to incoming president Park Geun-hye ahead of her inauguration next week that engagement with Pyongyang poses severe risks. For Japan, it dashes latent hopes for a breakthrough in the unresolved kidnapping cases of its citizens who were snatched off its beaches by North Korean agents. And for the US, the test is a vivid testament that the young, unpredictable and secretive leader Kim Jong-eun is pursuing a long-range nuclear capability – a growing risk to American security.

Yet North Korea’s big bang is primarily directed at and most keenly felt in Beijing, where a new generation of leaders is choosing its foreign policy underlings and policies for the years ahead. China’s relationship with North Korea is a complex mix of supposed ideological solidarity and deep mutual distrust. Despite the shared sacrifices of the Korean war and decades of (self-interested) Chinese support for the dynastic Kim regime, there is no love lost between these two.