The greatest concern for China is whether Mr. Kim’s death will lead to a rise in tensions on the divided Korean peninsula. That scenario could unfold if generals in Pyongyang, the capital of North Korea, try to reinforce their hold on power through aggression toward South Korea. Unlike China, where the Communist Party stands as the ultimate authority, the military is the final arbiter in North Korea…

China wants North Korea to stand strong as a buffer state that keeps American troops in South Korea at a distance, but relations between the two communist countries have had to endure complicated twists in recent years. Chinese officials were upset by North Korea’s sudden shelling of Yeonpyeong Island in South Korea in late 2010, and have lobbied North Korean leaders to refrain from further military actions, analysts say. Earlier in 2010, China was forced into an awkward position when South Korea and the United States accused North Korea of sinking the Cheonan, a South Korean warship, with a torpedo. The United States put pressure on China to agree with its allegation, which China refused to do.

Those incidents might have increased anxieties in China about North Korea, but they have also made North Korea more dependent on China for economic support. Two scholars of North Korea at the Peterson Institute for International Economics, Stephan Haggard and Marcus Noland, estimated in a paper published this year that China and South Korea alone recently accounted for 55 percent to 80 percent of North Korea’s trade. After the Cheonan sinking, most trade with South Korea stopped, so China became an even bigger partner.