North Korea again surprised the world on Jan. 6 by claiming that it had tested a miniature hydrogen bomb. While the actual type of bomb has yet to be confirmed, news of the test sent shockwaves reverberating around the world, especially for North Korea’s lead ally, China.

By defying China’s explicit advice against further nuclear tests and declining to provide prior warning, North Korean leader Kim Jong Un has openly challenged Beijing. China though, despite annoyance, is unlikely to punish North Korea for fear of harming its long-term strategic interests.

While the strategic challenge to the region remains clear, South Korean officials suggest the North Korean claim of having detonated a hydrogen bomb device should not lead to panic. Government scientists in Seoul do not rule out the possibility of North Koreans mixing hydrogen isotopes in the bomb, thus partly justifying the claim that it was a miniaturized hydrogen device.

China in the Dark

Kim left Chinese officials completely in the dark this time, demonstrating his displeasure over a number of developments poisoning bilateral ties, such as China’s strong pressure on the nuclear issue and support for UN sanctions against North Korea. Chinese foreign ministry spokeswoman Hua Chunying said Beijing will summon the North Korean ambassador to lodge a formal protest about the test.

The thrust of Pyongyang’s message seems to be more political than any indication of maturity in Pyongyang’s nuclear fusion technology. And it appears directed at China as a gesture of defiance and to pressure the United States to negotiate with North Korea as was done with nuclear-arms capable Iran. Official television news announcing the test displayed Kim’s handwritten authorization for the test signed on 15 December, just three days after Kim’s pop music band abruptly left Beijing before a premiere, complaining about China’s alleged attempt to change the repertoire glorifying the dictator and his nuclear bomb threats.

Chinese officials watching the band’s rehearsals are reported to have advised against the band’s video backdrop showing nuclear tests and a mock missile attack targeting the United States. The band leader is reported to have panicked, insisting that not one line could be changed without the dictator’s approval.

The band's visit was planned as a harbinger of improved relations, including Kim’s first official visit since he came to power in December 2011. That trip appears in jeopardy.

Historical Dilemma

Even so, the nuclear challenge isn’t expected to lighten the weight of China’s historical dilemma on its relations with North Korea. While the cost of maintaining relations with its chief client state remains considerable in terms of political irritation and economic aid, China can ill afford to abandon Pyongyang for historic and geopolitical reasons. The two countries share a 1300-kilometer border along China’s strategic northeastern region, and China fought against the United States during the 1950 Korean War, to keep the North from being reunified under South Korean control.

China-North Korea relations were being severely tested even before the latest nuclear gambit. Commenting on the state of affairs between Beijing and Pyongyang, former South Korean ambassador to China Kwon Yong Se observed during a television interview: “Beijing-Pyongyang relations are far worse than I had thought… China is quite at a loss as to how to respond.”

The tensions were hinted at several years ago, when an editor of a Chinese Communist Party publication in Beijing was fired for writing a commentary suggesting it was time for China to cut ties with North Korea.

Plenty of Leverage Left

China’s ambiguity doesn’t mean it has no leverage on the Pyongyang regime. Kim depends on China for food and energy shortages. As it faces another year of bad crops caused by a devastating drought in 2015, the North’s dependence on Beijing for food aid has grown. For China, the problem lies with the implications of its client state moving away from its sphere of influence.

Already, Beijing’s ever closer economic and diplomatic relations with South Korea have antagonized Pyongyang, prompting the regime to resort to provocations to attract attention. For China, North Korea’s worth is measured by its capacity for trouble-making.

On the wider issue of regional security, South Korea, Japan and the United States are equally concerned about Kim’s continuing pursuit of long-range ballistic missiles. While the regime continues to test a variety of short- and medium-range missiles, Joseph Bermudez, a top US expert on North Korean military, recently suggested that Kim is well on the way to developing submarine-launched ballistic missiles. In direct response to missile threats, the United States has proposed deploying Thaad, a Terminal High Altitude Air Defense anti-missile system in South Korea, presenting strategic implications for China. Alarmed by the prospect of US Thaad deployment near its borders, Beijing is pressuring Seoul to reject the US bid.

Meanwhile, resolution of the dispute between Japan and South Korea over comfort women during World War II has allowed the US to firm up its alliances with Seoul and Tokyo. That gives China little room for tolerating Pyongyang’s dangerous nuclear challenges.

Serious Reconsideration of Ties Unlikely

This strategic calculation may prompt China to reconsider its traditional concept of regarding North Korea as a tolerable burden. But only to a small extent. Few analysts in Seoul suggest that China can significantly alter its existing relations with North Korea given the weight of historical links and strategic interests. China’s official Global Times newspaper underscored this point on 11 December: “[T]he bilateral bond is not forged by minor details, but has strong strategies within. History and geopolitics are driving [North Korea and China] together, instead of pulling them apart.” The paper added, “It is impossible for a clean break to happen between the two, and this is becoming increasingly clear.”

While a clean break is unlikely, China must also mind its growing relations with South Korea. In recent years, Presidents Park Geun Hye and Xi Jinping have formulated close working relations, with Park joining China’s Victory March celebrating the 70th anniversary of the end of World War Two. Park was among the early supporters of the China-sponsored Asian Infrastructure Investment Bank despite Washington’s negative stance. The two countries have signed and ratified a free trade agreement, removing tariffs from most of manufactured goods.

Given such interlinking interests, Beijing is expected to continue supporting Pyongyang as long as it doesn’t deviate significantly from the status quo. China is signaling readiness to welcome Kim when he is ready to make his first official visit. This will likely occur shortly before May, when Kim is holding a party congress, another rite of passage for the young Great Leader.

For the time being, geopolitics is an overriding consideration for China as any serious internal trouble in North Korea could endanger security of the peninsula. The Korean Peninsula is the only spot on China’s map directly open to cross-border projection of US military forces. The strategic buffer North Korea provides makes it virtually impossible for Beijing to take any option that could change Pyongyang’s internal political disposition at the risk of creating huge disturbance. China finds itself in a proverbial place between the devil and the deep sea.

Shim Jae Joon is a journalist based in Seoul. This was written for YaleGlobal, the website of the Yale University Center for the Study of Globalization