Beijing's efforts to cajole and pressure Pyongyang into a more reasonable approach to the rest of the world have come to naught, but China's own needs suggest it will grit its teeth every time Kim Jong Un misbehaves.
When Chinese Foreign Minister Wang Yi arrives in Seoul on Monday, May 26, one issue will dominate the agenda of his talks with his South Korean counterparts: North Korea. Wang's visit will be the fourth high-level meeting between the two governments in recent months and another indication of the growing ties between Beijing and Seoul. That burgeoning relationship will be further cemented in June when Chinese President Xi Jinping pays a state visit to South Korea.
And while both nations would prefer to spend their time discussing ways in which they might be able to enhance trade, improve diplomatic and people-to-people exchanges and increase regional cooperation, their relationship will always be overshadowed by their erratic and belligerent neighbor.
And because that neighbor has developed nuclear weapons and is believed to be close to perfecting the ballistic missile systems required to deliver them, North Korea cannot be ignored.
The North's closest ally
For generations, China has been North Korea's closest ally, most visibly when hundreds of thousands of Chinese "volunteers" crossed the border to help stem the relentless advance of US-led United Nations forces during the 1950-'53 Korean War.
Had China not intervened in that conflict, which was triggered by North Korea invading the South on the assumption that the West would not rally to Seoul's assistance, then North Korea as it is today would not exist and the Kim family that has ruled it with a rod of iron since 1945 would have been consigned to history.
Even though the two nations share a relationship forged in blood, there are signs that Beijing has grown tired of the actions of Pyongyang.
North Korea has hinted that it is ready to carry out a fourth nuclear test, hinting that this blast will be its first test of a plutonium-based device, while its military fired dozens of missiles from sites on its east coast in April, coinciding with a visit to South Korea by US President Barack Obama.
South Korean navy ships fired warning shots at three North Korean vessels that crossed the sea border off the west coast of the peninsula on May 19, while state media have again ratcheted up the rhetoric against the US, Japan and South Korea, threatening to turn Seoul into a "sea of flames."
"China needs a peaceful international situation to allow it to concentrate on its own economic development," Joseph Cheng, a professor of international relations at Hong Kong's City University, told DW.
"Beijing does not want a conflict on its doorstep, but it also realizes that if North Korea becomes a full nuclear power, then there will be a great deal of temptation for South Korea and Japan to also go nuclear," he said. "And that would be a very undesirable development for China."
Beijing has attempted to convince North Korea that peaceful coexistence with its neighbors and the wider international community is in Pyongyang's best interests. It could, for example, dramatically improve the national economy and living standards of its people by adopting many of the industrial, agricultural and economic reforms that have transformed China in recent decades, Professor Cheng points out.
When cajoling has not had the desired effect, China has been more forceful. After the last nuclear test at North Korea's Punggye-ri proving grounds, Beijing surprised many by not vetoing a United Nations resolution and voting with the four other permanent members of the UN Security Council for additional sanctions on the regime.
To underline its displeasure, South Korean intelligence reports suggest that Beijing did not permit any critically needed fuel oil to cross the border into the North in the first three months of the year. That, they say, was an unprecedented period of time for such an important resource.
Cheng: "If North Korea becomes a full nuclear power, there will be a great temptation for South Korea and Japan to also go nuclear,"
"Yes, a subtle change has emerged since there have been troubles in the bilateral relationship," agrees Professor Cheng. "There are two sources for those changes; the first is domestic criticism in China, where an informed public and the intelligentsia feel that North Korea is becoming a liability and is only taking advantage of China. And all it does in return is cause problems for China and damage its interests.
"The second sense is that Beijing needs to exert pressure on Pyongyang to stop it carrying out a new nuclear test, for example," he said. "These are risky developments, adventurism, that put China in a very difficult position. "But, to date, it must be said that all the Chinese pressure has not had any effect."
The view from Pyongyang is quite different, with Kim Myong Chol, executive director of The Centre for North Korea-US Peace and a mouthpiece for the regime in Pyongyang, telling DW that China is "the only country in the world that understands North Korea." "We are friends and we are traditional allies," he said. "South Korea and the US totally misunderstand the situation."
"China will be happy when the next nuclear test is carried out - despite what they are saying in public - as we are their ally and a stronger North Korea means a stronger China," he said.
"And North Korea is important to China as well because without our support, it would be the odd man out in its confrontations with other countries in the Asia-Pacific region. "If they say they oppose our actions, that is purely political acting," he added.
China is wary of a reunited Korean peninsula, particularly if the new regime is controlled by South Korean interests
But whatever it may say in public about North Korea's actions, China's options are limited. Beijing does not want to pressure the regime in Pyongyang to the point that it collapses, causing a potentially volatile power struggle among heavily armed factions, including nuclear weapons. Such a collapse would also trigger a humanitarian disaster as millions of North Koreans would attempt to flee any conflict - with most of them likely to head for the border with China.
China is equally wary of a reunited Korean peninsula, particularly if the new regime is controlled by South Korean interests and is still heavily influenced by US foreign policy. And Professor Cheng says Kim Jong-un and his entourage are aware that China cannot afford to let North Korea fail. So that permits them to continue with the threats, the belligerence, the nuclear program and the systematic abuses of its own people.
"I cannot be optimistic," Professor Cheng admits. "The real challenge is to get North Korea to follow China's example and bring peace, but they are not willing to do that. "And if they do not engage in reforms, then they will have to depend on nuclear blackmail," he said. "All I can foresee is constant crisis and brinkmanship."