Despite international pressure, North Korea conducted its fourth nuclear test on 6 January
Many fear that this is a sign of the regime going rogue. This is a simplistic explanation
North Korea sees nukes as a guarantor of regime security
Though displeased, China can't be let off the hook for the help it gave to North Korea
More in the story
Circumstances that led to the nuclear tests
What are the consequences?
What was China's role?
North Korea's nuclear test of 6 January was its fourth since 2006. The world led by the UN Security Council was quick to condemn Pyongyang's action. The DPRK (Democratic Peoples' Republic of Korea, as North Korea is known) for its part blamed South Korea's propaganda broadcasts in the Demilitarised Zone - which includes K-pop songs, by the way - and deployment of military assets. It alleged that these acts were pushing the two countries to the 'brink of war'.
UN Security Council resolutions since 2006 imposing and strengthening sanctions on North Korea for continuing to develop its nuclear weapons and ballistic missiles have not dissuaded Pyongyang, even if they have slowed down the pace of development of these programmes. This is because North Korea views nuclear weapons as a guarnator of regime security.
Given American efforts at regime change in West Asia, Pyongyang sees nuclear weapons as essential to the surival of the DPRK. The Americans reminded Kim Jong-un's regime of that threat by flying a B-52 over South Korea in a joint response to the North Korean test. The bomber that took off from far-away Guam, is equipped to carry both conventional and nuclear weapons.
The test, notwithstanding doubts about whether it was a hydrogen bomb, is not entirely surprising. DPRK officials have themselves been speaking of tests for over a year. What is surprising is that the North Koreans had also spent considerable effort last year trying to repair relations with the rest of the world, which now appear to have been wasted. And so the timing of the test still requires some explanation.
Both from a regional perspective and from a regime perspective, South Korea's growing international clout must be a concern for DPRK leader Kim Jong-un and his advisers. It is notable that close ally Chinese leader Xi Jinping has not met Kim, a fellow communist, till now. Xi has only deputed other senior members of the Chinese leadership to visit North Korea or to deal with visitors from that country. In contrast, Xi has met his South Korean counterpart Park Geun-hye well over a dozen times and the two countries signed a landmark FTA in mid-2015.
Some dramatic shake-ups, including purges and executions of close advisers at home, also suggest that Kim Jong-un's position might not be entirely a settled affair. Hence the resort to such dramatic and seemingly counter-productive behaviour as nuclear tests.
The consequences of the latest North Korean action are many. It will probably impart greater momentum to the solidification of defence ties between South Korea, the US and Japan. This is something that the other participants in the Six-Party Talks - Russia and China - cannot be too happy about, either.
In fact, Japan had established its National Security Council in 2013, citing North Korea's rising nuclear ambitions and the latest North Korean test was possibly the first time that the hotline between the South Korean and Japanese defense ministers was used. Japanese Prime Minister Shinzo Abe declared in parliament that his country would take 'undaunted but firm action'.
Indeed, in addition to the perceived threat from China, Pyongyang's actions too have allowed Tokyo to justify much of the changes in its defence posture in recent years.
This is another reason why the Chinese are displeased, to put it mildly, with their ally. The Chinese are, however, constrained by the reality that a Korean re-unification would most likely bring the Americans to their borders.
China-North Korea relations have not been easy either. The decline in total China-DPRK trade volume between in January to November 2015 by about 15% over the same period in 2014 to US$4.9 billion probably owes much to the deterioration of bilateral ties. While China had begun to reactivate some of its assistance programmes following the North Korean diplomatic outreach over the past year, these have now once again been jeopardised.
Other than express frustration or embarrassment at Pyongyang's actions, it would seem then that there is little that China can do about its prodigal neighbour and ally. However, to believe that Beijing has little control over North Korea's actions seems to be a case of cutting China rather too much slack.
Without the lifeline extended by China through food and fuel supplies as well as banking services, Pyongyang could not possibly carry through with any of its plans. It certainly can tighten the financial screws on the North Korean elite while refraining from restrictions on fuel and food supplies that affect ordinary North Koreans the most.
The development and proliferation of nuclear weapons by North Korea is no random, irrational activity but a carefully considered exercise in obtaining both strategic and pecuniary benefits. Thus, the portrayal of the Pyongyang regime simply as one gone 'rogue' only deflects attention from China's responsibility and indirect support for nuclear proliferation, including for the Pakistan-North Korea linkage.