For the second time in four months Kim Jong Un has dared to humiliate Chinese president Xi Jinping, the one foreign leader with the power to strangle North Korea’s economy with potentially fatal effects for the Pyongyang regime.
Mr Kim not only conducted a nuclear test on Sunday knowing that it would enrage Beijing; he did so as his Chinese counterpart was preparing to receive the heads of Brazil, Russia, India and South Africa in the coastal city of Xiamen.
The test set off a magnitude 6.3 quake that shook the ground in Yanbian, an area in China’s Jilin province near the North Korean border. On Sunday night China’s environment ministry said it would be monitoring border areas for radioactive fallout.
Sunday’s test came less than a week after Mr Kim’s regime lobbed a missile over Japan — a calculated insult against Tokyo and its US ally. On Sunday US President Donald Trump implied that North Korea’s nuclear test was an affront primarily to China, whose territory was literally shaken by the aftershock.
“North Korea is a rogue nation which has become a great threat and embarrassment to China, which is trying to help out but with little success,” Mr Trump tweeted.
But it is still unclear if even such an insult delivered on the eve of a major Chinese event would convince Mr Xi to use one of the most potent measures it has yet to deploy against North Korea — blocking the regime’s oil supply.
Just as Mr Trump’s recent threat to rain “fire and fury” on Pyongyang is widely seen as hollow given the potential devastation from a counterattack on Seoul, Beijing’s room for manoeuvre is similarly constrained by fears of the refugee crisis that could be triggered by a North Korean economic and political collapse.
“This nuclear test is one of the few things that might trigger a cut-off of oil supplies, but we are still very reluctant to do so,” said one person close to Chinese foreign policymakers. “As far as North Korea is concerned, Trump and Xi might both be paper tigers.”
“China sees sanctions as punishment for bad behaviour rather than an effective means of achieving disarmament,” agreed Michael Korvig at the International Crisis Group.
Mr Korvig was in Yanbian on Sunday and felt the ground shake after the test. “I doubt [China] would cut off oil supplies because that could risk triggering a North Korean economic crisis and retaliation,” he added.
Mr Xi’s meetings this week with his Brazilian, Russian, Indian and South African counterparts — representing the so-called Brics nations — is the second most important international event Mr Xi has hosted this year.
His most important one — a forum in May for his “New Silk Road” initiative to strengthen infrastructure links across the Eurasian land mass and into Africa — was similarly overshadowed by North Korea’s successful test of an intermediate range missile capable of hitting the US territory of Guam.
On Sunday evening China Central Television’s main news broadcast led with the Brics summit and dedicated more than half of its airtime to it, while mentioning the North Korean nuclear test in only a brief statement at the end of the programme.
While Mr Xi did not refer directly to North Korea in Xiamen on Sunday, he said that terrorism, computer hacking and “other threats” had “cast a dark shadow over the world”.
Shi Yinhong, a foreign relations expert at Renmin University in Beijing, believes that Mr Kim’s repeated provocations are evidence of the young ruler’s “determination and confidence”.
“Kim Jong Un doesn’t care what the US and China do,” Prof Shi said. “The increasingly broad and strict UN sanctions are painful but he also knows he is progressing towards his final objective of an operational nuclear missile.”
“Under American pressure, China has made major concessions over North Korea again and again,” he added. “China has lost almost all room for manoeuvre in its North Korea policy.”
For Mr Xi, the headaches and embarrassments he must regularly endure because of Mr Kim are particularly galling given his personal antipathy for the young ruler.
While Chinese officials are routinely disdainful of the North Korean ruler in private, last week Washington’s former ambassador to Beijing let slip that their president is as well.
“The most derogatory expression I’ve ever heard President Xi use was his description of Kim Jong Un,” Max Baucus said in an interview with the BBC after North Korea’s nuclear test over Japan. “He just does not like that man.”