During the past few years, China has been a major player in the six-party talks aimed at persuading North Korea to give up its nuclear weapons program.

The conventional wisdom is that China is North Korea's staunchest ally and is Pyongyang's greatest source of support in the international community.

Daniel Sneider, a China expert at Stanford University's Asia-Pacific Research Center, says the two countries have a long and close historical relationship. "It was the Chinese who intervened in 1950 to save North Korea from disappearing from the face of the earth at the hands of General MacArthur. And the Chinese were long-time allies of North Korea during the decades after that -- they were suppliers of military equipment, of aid. They were ideological allies," says Sneider.

Economic and Historic Ties

The two countries also share a [1360 kilometer] border and there is a significant Korean minority population in northeast China. On the economic front, Beijing is Pyongyang's major supplier of food and energy.

Daniel Pinkston, a Korea specialist at the Center for Nonproliferation Studies in Monterey, California, says Chinese companies conduct trade with North Korea on different levels.

"There are very large firms, kind of state-run enterprises that are doing the major trade in oil and grains. And then you have some intermediate or smaller firms - - and some very, very small family firms that put together these kinds of cross-border trade or 'suitcase' [i.e., small caliber] trade," says Pinkston.

Despite these close economic and historical ties, experts say the relationship between China and North Korea is far from cordial.

Jim Walsh is a security expert with the Massachusetts Institute of Technology and he has traveled to North Korea on several occasions.

"When I was in North Korea, it was clear to me that the North Koreans have a love-hate relationship toward the Chinese. They feel an emotional and historical bond to China. It's a relationship born in history and blood. On the other hand, they see themselves as a little country surrounded by giants. So they are wary and suspicious," says Walsh.

Daniel Sneider from Stanford University agrees. "If you talk to North Koreans about China, it doesn't take very long for them to express a fair amount of hostility, even contempt for the Chinese. Koreans in general -- and North Koreans -- they do not like being dictated to. These are very proud people, very nationalistic and they really bristle at the idea that they are, somehow or other, at the beck and call of the Chinese. They do look for opportunities, in some sense, to put their thumb in the Chinese eye, just to make it clear that they can't be pushed around," says Sneider.

Korean Missile Launches

Sneider and others say the latest example of North Korea's attempt to show some independence from China is Pyongyang's recent test launching [July 4] of several ballistic missiles.

Adam Segal, China expert with the Council on Foreign Relations, says most of them were of the short and medium-range variety, but one of them was a long-range ballistic missile known as the Taepodong-two that could -- theoretically -- hit the United States.

"The United States spent a lot of time focusing on the Taepodong-two. But all of the other missiles that were launched have a range that could include China. So clearly, there was a message to be sent to China and to South Korea and to Japan about North Korea and what it could do to the regional players," says Segal.

Experts say the launch was an embarrassment for China, because Beijing had publicly urged North Korea not to go ahead with the tests.

Daniel Pinkston says the Chinese have also used their diplomatic skills by trying to revive the six-party talks aimed at persuading Pyongyang to end its nuclear weapons program.

"And they have been urging, particularly urging the United States and North Korea to show more flexibility and return to the negotiating table - - and so this made things more difficult. It has given Japan reasons to expand its military capabilities and expand its missile defense program, which China is not happy with. So it does increase a number of complexities in the region that make China uncomfortable," says Pinkston.

Analysts say Pyongyang's missile launches prompted China to vote for a United Nations resolution condemning the tests. But China agreed to the text only after an original draft was watered down.

China's Leverage 

Daniel Sneider says the Chinese have always opposed resolutions urging strong sanctions against Pyongyang because they fear such measures could de-stabilize the region.

"They are worried about the possibility of conflict triggered either by North Korea or the United States. And they want stability -- stability on their borders and to some degree, they want to preserve the regime that's in power in Pyongyang while they encourage it to reform. So all those goals are operating at the same time. And I think stability, in some sense, trumps everything," says Sneider.

Experts agree that if there is a country that could prompt North Korea to resume negotiations on its nuclear weapons program, it is indeed China.

But Sneider says Beijing's leverage over Pyongyang is limited. "I was in Beijing just a few weeks ago when the missile crisis had just begun. And I was talking to Chinese North Korea specialists, in particular. And they will always tell you, 'Look, you Americans overestimate our leverage.' We can't simply dictate to the North Koreans. The North Koreans do not listen to us in that way." But Sneider and other experts say China does still have some leverage, especially in the economic area. Analysts say the Chinese government must be trying to figure out how much pressure they can exert and how far they can go before they trigger instability in North Korea and potentially, an even worse crisis.

This story was first broadcast on the English news program,VOA News Now. For other Focus reports click here.