BEIJING — President Obama flew to South Korea Wednesday, ending his maiden visit to China and leaving behind a strong impression that the new partnership he seeks with the Asian giant remains to be built, issue by issue.

Mr. Obama and his Chinese host, Hu Jintao, spoke enthusiastically of their two countries' common interests and their prospects for cooperation. It is clear, though, that as China plays an increasingly active role on the world stage, Beijing will not always be at Washington's side.

"Often what makes them agree is their interdependence, more than what they have in common," says David Zweig, a political analyst at the Hong Kong University of Science and Technology. "They do not necessarily have the same interests."

That leaves the two countries in "an awkward situation," adds Jiang Wenran, who teaches Chinese politics at the University of Alberta. "Their agendas do not coincide ... but both feel that their relationship is too important to allow discord to distract them."

That awkwardness was on physical display Tuesday in the presidents' joint appearance before the press. They were stiff and separate, addressing nary a word to each other, as each ran through a list of his primary concerns.

On the subject of Iran, for example, where Washington is seeking greater Chinese support for a threat of sanctions if Tehran does not properly explain its nuclear program, Obama said Iran faced "consequences" if it failed to do so.

"On this point our two nations ... are unified," he said.

Mr. Hu, however, stuck to the much vaguer and traditional Chinese formulation that it was "very important ... to appropriately resolve the Iranian nuclear issue through dialogue and negotiations."

Addressing the thorny issue of the weakness of the Chinese currency, which gives Beijing's exports an advantage, Obama said he was "pleased to note the Chinese commitment, made in past statements, to move toward a more market-oriented exchange rate over time."

His reference to "past statements" suggested that Hu had made no new pledges. And deputy Foreign Minister He Yafei later indicated Beijing has no plans for the time being to let the renminbi strengthen, calling its recent stability against the US dollar "a contribution to the stability of world financial markets."

On Afghanistan, where American officials hope to persuade China to play a more active role in restoring that country's infrastructure, they won from Hu no more than a promise to help counter terrorism by "bringing about more stable, peaceful relations in all of South Asia."

Beijing's reluctance to line up behind Washington, even on issues of such importance to US policymakers, is not surprising, says Professor Jiang. "Obama brought an agenda very much tailored on US priorities," he says, "China does not perceive them as core interests."

At the same time, he adds, "it is not realistic to expect Obama to come in and get major Chinese concessions on all these issues in two days."

US officials made the same point. The president had not expected that "the waters would part and everything would change" during the visit, White House spokesman Robert Gibbs told reporters. "We understand that we have a lot of work to do."

That work will involve a lot of patient persuasion, suggests Shi Yinhong, a US expert at Renmin University in Beijing. "This is a partnership. It should be based on consultation, not on dictation," he says.

And on some key issues, even consultation is unlikely to bear fruit, he warns. "China has a different understanding of the situation" in Iran from the United States, he points out, along with "different interests and principles. If the US pushes more harshly, China will resist more firmly."

That resistance, he says, will be born of "China's growing self-confidence. China is less compromising than before." In an era when both sides need each other's help to cope with their economic and strategic problems, he adds, "the relations of dependence have changed."