How do you solve a problem like Korea?

In February 2016, it seemed that China and the United States had reached the end of their tether with North Korea. The Chinese foreign minister Wang Yi agreed with the US Secretary of State John Kerry on a new UN resolution to tighten sanctions on Pyongyang. This was a reaction to two recent challenges: a nuclear test and a satellite launch. Since 90 per cent of North Korea’s trade is with China, which supplies everything from oil to internet and banking services, it has the greatest capacity to squeeze the regime and its support for sanctions is critical. In February this year, China announced a further measure: a ban on imports of North Korean coal, worth around $1bn a year.

So it might seem surprising that China’s trading figures for the first quarter of 2017, a time when tensions have rarely been higher, revealed that its trade with North Korea had increased sharply: exports rose by 54.5 per cent and imports up by 18.4 per cent, compared to the same quarter last year. Seasoned observers, however, kept their surprise in check. It has long been evident that China’s effective stance towards North Korea is not really the strategic patience favoured by former US president Barack Obama’s administration, but strategic ambivalence.

As well as trade, China gives diplomatic protection and a security guarantee under a 1961 treaty obliging it to defend North Korea in the event of an attack (an arrangement North Korea no longer seems to trust.) Beijing also works to prevent the regime collapse it dreads. Keeping Pyongyang afloat, by definition, implies maintaining the ruling Kim dynasty. With the murder of Kim Jung-un’s half brother in Malaysia in February, there is no obvious alternative to the incumbent, however troublesome. For China, this relationship is “as close as lips and teeth,” an expression that once signalled communist solidarity. Today it merely implies an unavoidable co-dependence. If the lips are gone, the saying continues, the teeth are exposed. If North Korea collapses, a nation unified under the terms of South Korea, a US ally, would be China’s immediate neighbour. For a country in the grip of its own muscular nationalism, that is an intolerable outcome.

China’s border with North Korea is long and porous. It is one of the most used escape routes, although North Korean refugees often find themselves trapped in exploitation or sex slavery in China. It is also the border where China’s covert and overt support to North Korea is most visible. In the Chinese town of Dandong, near the mouth of the Yalu River, Chinese tourists gawp at the North Korean sentry posts on the other side. In the Dandong Border Economic Zone linked by bridge to the Korean town of Sinuiju, Korean workers bend over rows of sewing machines, making garments labelled “Made in China” for international markets. North Korea’s own special economic zone across the river turns out light industrial goods for China and recycles rubbish.

Dandong epitomises China’s prescription for stability on the Korean peninsula: that Kim Jong-un should follow Deng Xiaoping’s development model, which has led China out of the Maoist doldrums to success in the global economy. It is a recipe for a kind of normalisation and, in China at least, the regime has so far survived the transition. There are signs that North Korea is following the plan: local markets have sprung up; farmers can sell their surplus privately and some factories can make their own supply and production arrangements, tentative moves from China’s 1980s playbook. The regime still has enough hard currency to import foreign cars for its well-dressed, privileged elite and to build new apartment blocks and leisure facilities in the capital, on top of financing its ruinously expensive military.

But official relations between Pyongyang and Beijing are, paradoxically, at a historically low ebb. Both his father and grandfather visited Beijing regularly, but Kim Jong-un has never paid homage to his giant neighbour. The Chinese president Xi Jinping’s itinerary has taken him to Seoul but never to Pyongyang. Perhaps Kim is too insecure to leave home, or possibly keen to demonstrate that he is not, after all, dependent on China. A weak and isolated North Korea could easily become a virtual province of China. Conduct that is often interpreted as petulant or irrational, including the nuclear programme and extravagant threats to the US, help make the point at home that North Korea bows to nobody.

The Kim dynasty’s god-like status is predicated on the myth that its founder, Kim Il-sung, heroically defeated the Japanese in the Second World War, then led his country to victory in the Korean War against the combined forces of imperialism. In fact, when, more than 70 years ago, two young US officers, alarmed at the Soviet forces’ rapid advance south, hastily drew a line across the peninsula at the 38th Parallel and the US adopted South Korea as a Cold War poster child for capitalism, Stalin installed Kim Il-sung in the north. He had spent most of his war in Manchuria and held a junior commission in the Soviet army. His rule lasted 46 years and on his death in 1994 he was succeeded by his son Kim Jong-il (though posthumously awarded the title Eternal President of the Republic.) On Kim Jong-il’s death in 2011, his son Kim Jong-un became leader.

The Kim Il-sung legend has North Korea emerging from its baptism of fire as strong and unyielding as well-tempered steel. A continuing sense of threat, with its concomitant extreme nationalism and militarism, centred on the personalities of successive generations of the Kim family, is the bedrock of the regime’s survival. The nuclear programme, far from irrational, is the guarantee that Kim Jong-un and those around him will not fall to superior conventional forces, as did the non-nuclear leaders Saddam Hussein and Colonel Muammar Gaddafi.

Kim knows that with China, Japan and South Korea within range of his missiles, the US is obliged to acknowledge that this nuclear capability raises the costs of military action against North Korea’s large, if poorly equipped conventional forces. Even if it fails to develop a nuclear missile capable of striking the US, the 47,000 US troops stationed in Japan are well within reach and Seoul is within artillery range. Kim’s rhetoric may be extravagant and his propaganda risible, but he follows his father’s example of playing a poor hand to maximum effect.

South Korea, too, was a dictatorship in the post-war years, with espionage and propaganda to match the North in its virulence: defectors were—and still are—encouraged to tell stories of their suffering, and while undoubtedly there is much truth to this, some more extravagant accounts have been discredited. Today, South Korea’s official position is still that the two Koreas must reunite, but the preferred path to this has varied. For 10 years, the liberal presidents Kim Dae-jung and Roh Moo-hyun promoted the often criticised “sunshine policy” of peaceful engagement, encouraging investment and trade with the north.

South Korean firms invested in mining, agriculture, tourism and manufacturing and an industrial park was built in the North Korean city of Kaesong, that employed some 53,000 North Koreans in South Korean enterprises. South Korea withdrew from Kaesong in 2016, but the “sunshine policy” ended in 2008. Since then, relations have been hostile. Now the election of South Korea’s liberal new president, Moon Jae-in may signal a return of the sunshine approach. As with China, regime collapse figures in South Korea’s nightmares. To be obliged to absorb a country whose most effective arm of the state is the military, steeped in hostility to the south, would be unthinkably complex. Like China, its best hope is a nuclear freeze and gradual normalisation through economic development. Unification, in Seoul, is like St Augustine’s prayer for chastity: desirable, but not yet.

Of all North Korea’s difficult relationships, that with Japan has yielded the most bizarre episodes and the most intractable hostility. Geographically closer to China, Korea is culturally closer to Japan. The intensity of Kim worship recalls Japanese worship of the emperor in the early 20th century more, even, than China’s cult of Mao Zedong in his final years. The two cultures display a fraternal hatred, exacerbated by similarities. In North Korea, guides insist Korea is the original culture from which that of Japan is derived. In Japan, Korean residents suffer virulent discrimination. Memories of Japanese abuse and the humiliations of its 1910 annexation of Korea keep resentment active in both north and south. For Japan, North Korea’s bizarre kidnappings of several of  its citizens in the 70s—including a schoolgirl snatched on her way home—and the regime’s failure to account for their fate, renders normal relations politically impossible.

North Korea’s military threat to Japan is growing: Tokyo estimates it has 3-400 medium-range missiles, some of which could carry nuclear weapons. This affects domestic politics in Japan, the only country ever to suffer a nuclear attack. Some demand the scrapping of Article 9 of the Japanese constitution, which renounces war, to permit Japan to acquire an offensive capability.

Trump’s questioning of old alliances has set off more alarm bells in Tokyo. If the US is no longer a reliable friend, the argument goes, Japan has no choice but to rebuild its military capacity. This, like the US’s recent deployment of anti-ballistic missiles in South Korea, would raise tensions further with a China concerned with the region’s shifting strategic balance. As its defence ministry spokesman put it recently, “China opposes any actions by other countries to take the nuclear issue as an excuse to compromise the security of other countries.”

Japan’s best hope—full de-nuclearisation—is also the least likely. One essential precondition would be a cast iron security guarantee for North Korea, backed by China. But a regime that thrives on paranoia will put little faith in promises that could be torn up by the next—or current—US president. Having cut back its economic ties, Japan enjoys little leverage and, like the US, now hopes China can force North Korea to agree to a nuclear freeze. One major imponderable is whether North Korea can develop an Inter-Continental Ballistic Missile without outside help. Its submarine-launched missile programme, which has grown rapidly, seems largely home-grown, but there has been much assistance in the past, from Pakistan, Russia and Iran, as well as Chinese corporations, if not the regime itself.

Japan is acutely aware that the Trump presidency adds alarming unpredictability to an already volatile situation and Japanese diplomacy has been in overdrive, with Shinzo Abe’s early visit to the US and obligatory round of golf with Trump. Japanese officials say that they welcome Washington’s commitment to the region. Behind the scenes, many have their fingers crossed, noting that both Kim and Trump make unrealistic claims to their domestic constituencies. Neither is noted for graciously backing down; both would wish to present any compromise as a victory over the other. All of North Korea’s neighbours are searching for a proposition that satisfies two lethally armed and unpredictable leaders in this most dangerous of situations.