Biden, in Japan, Calibrates Message Over Tensions With China Toru Yamanaka/Agence France-Presse - Getty Images United States Vice President Joe Biden during a joint press conference with Japanese Prime Minister Shinzo Abe in Tokyo, on Tuesday. TOKYO - Vice President Joseph R. Biden Jr. delivered a carefully calibrated show of support for Japan on Tuesday, declaring the United States was "deeply concerned" about China's move to control airspace contested with Japan. But he stopped short of demanding that China retreat, and urged the feuding neighbors to talk to each other. Mr. Biden's statement, at the start of an unexpectedly challenging trip to Asia that includes a stop in Beijing, captured the strategic complexities for the United States in the tense showdown between Japan and China over disputed claims in the East China Sea. China, Mr. Biden said, was trying to "unilaterally change the status quo in the East China Sea," with an air defense identification zone that he said "raised regional tensions and increased the risk of accidents and miscalculation." He said he would raise the American concerns in detail when he meets with the Chinese leadership on Wednesday. But rather than call for China to roll back its defense zone, as the Japanese government has called on China to do, Mr. Biden said that China and Japan needed "crisis management mechanisms and effective channels of communication" to avoid the risk of an accident or miscalculation. "The only conflict that is worse than one that is intended is one that is unintended," Mr. Biden said, quoting his father, as an unsmiling Prime Minister Shinzo Abe stood next to him. For his part, Mr. Abe said the United States and Japan would "not tolerate the attempt by China to change the status quo by force." He said both countries reaffirmed that they would not alter any joint military operations because of China's zone, and he added, "We will not condone any action that will threaten the safety of civilian aircraft." That appeared to be an attempt to smooth over a disconnect between the United States and Japan over the weekend, after the Federal Aviation Administration advised American carriers to identify themselves when entering the restricted zone. The Japanese government has instructed its carriers to ignore the Chinese demand. Administration officials insisted there was no daylight between the United States and Japan on how to respond to China's move. The F.A.A.'s guidance, they said, was no different than it would have been in any other case where a country issued a warning to planes or ships. "Nothing that F.A.A. has done constitutes any acceptance or recognition of this," said a senior administration official who is traveling with Mr. Biden. The U.S. has clearly set forth that our military aircraft will continue to operate normally. Administration officials said Mr. Biden would urge China not to create any other such zones and to show restraint in policing this one. But neither the vice president nor his aides made any reference to asking the Chinese to rescind its action. The Japanese government perceives the Chinese air defense identification zone, which covers a wide swath of the East China Sea, as an attempt by the Chinese to assert control over a clump of disputed islands, known in the Japan as the Senkaku and in China as the Diaoyu. Japan has a long-established air defense identification zone of its own that covers much of the same area of the sea, including the islands. The dispute has raised tensions in the region to their highest level in nearly two decades. In Beijing, a foreign ministry spokesman, Hong Lei, said China's defense zone was fully in compliance with international law. Mr. Hong suggested that China was open to the idea of establishing crisis-management mechanisms. But he quickly added that Japan was not. "The Japanese side unilaterally, on one hand, declares they want dialogue, but then they close the door to dialogue," he said. We ask the Japanese side to change their mistakes. For Mr. Biden, the dispute has been a distraction on a trip that he hoped would cover a range of other issues, from a trans-Pacific trade agreement to the nuclear threat in North Korea. But Mr. Biden still found time to tour a Japanese Internet company founded and run by a female entrepreneur, Tomoko Namba. Joined by Ambassador Caroline Kennedy, he chatted with five female employees in a leather banquette at the company's sleek Tokyo offices. Do your husbands like you working full-time? Mr. Biden asked the women, who nodded energetically. He also inquired whether the company, known as DeNA, offered child-care service and whether female employees were allowed to work from home. Mr. Biden seemed to delight in being accompanied around Tokyo by Ms. Kennedy, whose name has given her celebrity status in a post that has frequently been held by prominent political figures, including one of Mr. Biden's predecessors, Walter F. Mondale. Before his meeting with Mr. Abe, the vice president jokingly introduced himself by saying, "My name is Joe Biden, and I'm accompanying the ambassador" - a line that echoed John F. Kennedy's famous quip when he was overshadowed on the presidential trip to France in 1961 by his glamorous wife, Jacqueline Kennedy.