Biden often relies on his affability and talent for personal relations when he meets foreign leaders and he feels he has a bond with Xi who he has known since before the Chinese president took office.
"He has a way of saying to somebody, 'I understand the predicament you're in, and far be it from me to tell you what to do, but I'm going to offer some advice,'" said Julie Smith, who was Biden's deputy national security advisor until June.
"Because he's got this personal relationship with Xi, they take him very seriously," Smith said. "They view him as an honest broker."
All the same, Biden's well-known frankness can go too far and he upset Chinese students at a speech at the University of Pennsylvania in May when he told them China's communist system does not allow them to "think different."
An immediate resolution to the air defense zone dispute is unlikely, said Jia Qingguo, professor and associate dean of the School of International Studies at Peking University.
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"China will probably say to Biden that this is a standard practice for more than 20 countries. Why the fuss?"
"It is helpful for the two sides to gauge each other's intentions and clarify issues and develop some kind of understanding as to what to expect. But this issue will probably linger on. It is good for Biden to come at this time so that this issue gets discussed at a high level. Other issues need attention too," Jia said.
Despite the military standoff, U.S. officials see increased cooperation on a range of issues from climate change to North Korea's nuclear weapons ambitions a year after Xi took over the helm of the Communist Party.
It is not clear whether Biden will ask for Chinese help in pressuring North Korea to release U.S. war veteran Merrill Newman, 85, who it arrested last month.
The Biden visit goes some way to addressing concerns among U.S. allies in Asia that Washington is neglecting the region because of budget fights at home, Iran nuclear talks and the Syrian civil war.
Obama canceled a trip to Southeast Asia in October because of the partial U.S. government shutdown, and a much vaunted "pivot to Asia," a strategic rebalancing of U.S. priorities toward the Pacific, has yet to show many results.
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Obama's national security adviser, Susan Rice, announced in November that Obama would travel to Asia in April to make up for the canceled visit.
"The fact that (Biden's) visit encompasses both America's allies and America's chief rival in the region is intended to show that the United States is the only power able to maintain the balance in the region, which is absolutely what the pivot was all about," said Eyal, of the Royal United Services Institute.
He said "a prevalent mood in Asia that the administration hasn't got the stomach for military action and is disinterested in Asia" may have propelled China to announcing its defense zone.