East Asia's triangle

Beijing's relations to North and South Korea are a clear example that theory does not necessarily go hand in hand with practice. In theory, North Korea is supposed to be China's closest ally. Over 50 years ago, both countries signed the Treaty of Friendship, Cooperation and Mutual Assistance, thus committing themselves to defending one another in the case of conflict.

But in practice, China has had a troublesome relationship with its wayward "little brother," especially after Pyongyang conducted a third nuclear test in February, despite Beijing urging it not to. This prompted China to vote in favor of a UN Security Council resolution condemning North Korea's actions and imposing sanctions against its regime. Pyongyang's execution of Kim Jong-Un's uncle, Jang Song Thaek - who was China's most important contact among the North's ruling elite - has further strained the relationship.

This development stands in stark contrast to Beijing's relations to South Korea, which normalized in 1992. In a little more than two decades, South Korea has become China's third-largest trading partner. One fourth of Seoul's exports go to China, making it the country's biggest trading partner. While bilateral trade stands at around 230 billion USD, South Korea currently enjoys a hefty trade surplus of some 60 billion USD.

North Korea isolated, South Korea courted

The close ties between the two nations are highlighted by the fact that Xi Jinping opted to visit South Korea before paying respects to the comrades in the north. Moreover, since Kim Jong Un assumed power at the end of 2011, no foreign leader has so far visited the isolated nation. At the same time, Xi Jinping and South Korean President Park Geun-hye have already met four times, despite both leaders taking office only last year. "South Korea is more important to China than North Korea," says Liu Jiangyong, political scientist at the Tsinghua University in Beijing. That's just the reality and also "a logical consequence of the market economy," he added.

Daniel Pinkston, Korea expert at the International Crisis Group (ICG), considers the Chinese and South Korean economies to be closely intertwined. The reason for this is that there are several so-called global supply chains in Northeast Asia, he says, adding that some parts of the production process take place in different countries.

"This degree of integration makes countries and companies vulnerable to disruptions, forcing them work more closely together", Pinkston told DW, adding that the integration also creates incentives for all sides to keep up the economic cooperation. It is expected that the expansion of economic cooperation will be high on the summit agenda.

Park's 'trust-building' policy

Besides economic ties, both leaders will also discuss the regional security situation during their meeting. Pyongyang conducted missile tests just days before Xi's South Korea visit and Xi and Park are expected to discuss the disputes surrounding North Korea's nuclear and missile programs.

While China has long been seeking to start new multi-party talks on Pyongyang's nuclear program, South Korea and the US have been demanding concrete steps from the North towards disarmament. President Park, however, declared a new 'trust building' policy towards the country's northern neighbor at the start of her term.

According to Pinkston, Park's 'trust-building' policy involves offering dialogue to the North Koreans but no concessions without reciprocity. "She has made it clear that Seoul will cooperate as long as Pyongyang does the same. But she also stated that South Korea would react accordingly, if the North re-engaged in bellicose and uncooperative behavior." In light of Beijing's growing frustration with North Korea, Park is likely to push China to exert pressure on Pyongyang. However, despite the displeasure with the actions of Pyongyang, China has been so far not willing to press its ally.

Wasted potential

Furthermore, North Korea's economy is nearly completely dependent on China; 70 percent of its foreign trade is done with the giant Asian power. The North receives around 90 percent of its oil, 80 percent of consumer products and 45 percent of its food from China.

Nonetheless, Cai Jian, Korea expert at Fudan University in Shanghai, is skeptical. He told DW that this dependency means that pressure could be exercised. "But Beijing will hold back" because China's strategic interest is to maintain the status quo on the Korean Peninsula, he said. "China does not want to exert too much pressure to the point that the North becomes unstable or even possibly falls apart."