TOKYO — Caroline Kennedy arrived in Japan on Friday to take up her position as U.S. ambassador with one important strength: She has the ear of the American president.

Japan hopes the 55-year-old daughter of late President John F. Kennedy will work closely with President Barack Obama to tackle some urgent U.S.-Japan matters, analysts said.

"What's important here is her strong pipeline with Obama and an ability to be able to pick up the phone and speak with Obama directly in the middle of the night for consultation on urgent matters," said Ryuichi Teshima, professor of diplomacy at Keio University in Tokyo.

Kennedy's close ties to Obama come from playing a pivotal role during the Democratic presidential primaries in 2008 by endorsing him when Hillary Clinton was the lead candidate.

As the first woman to serve as U.S. ambassador to Japan, Kennedy may also be a role model in a country that traditionally has restricted the role of women, said Toshihiro Nakayama, professor of international politics at Aoyama Gakuin University.

U.S. ambassadors to Japan can be grouped into three categories, he said. They are big political names, Japan experts and those with close ties to the president. Former Vice President Walter Mondale and former Sen. Mike Mansfield fall into the first type. Edwin Reischauer, President Kennedy's envoy, would be the second.

Nakayama puts Kennedy, an attorney and author, in the third group, along with her predecessor, John Roos, a Silicon Valley lawyer and Obama fundraiser, and Tom Schieffer, who was George W. Bush's business partner in the Texas Rangers baseball team.

U.S.-Japan relations are generally on an even keel, but Obama and Japanese Prime Minister Shinzo Abe are not as close as some would like. "The chemistry is off, possibly because Obama does not support the right-wing views Abe holds," Teshima said.

Major bilateral issues include the Trans-Pacific Partnership trade talks, the relocation of a U.S. military base on Okinawa and a revamp of defense cooperation guidelines between the two countries.

"It's a critical time in U.S.-Japan relations," Kennedy said at a reception at the Japanese embassy in Washington earlier this week. "The U.S.-Japan relationship is the cornerstone of regional prosperity, stability and security."