ROUGH CUT (NO REPORTER NARRATION)<br/> <br />U.S. Vice President Joe Biden arrived in Tokyo on Monday as a dispute simmers over Beijing's recent claim of a large swathe of airspace in the region.<br/> <br />Newly appointed U.S. ambassador to Japan Caroline Kennedy was at the airport to greet him.<br/> <br />Biden is hoping to seek a delicate balance between calming military tensions with China and backing ally Japan against Beijing on a trip to Asia this week that is being overshadowed by the territorial row in the East China Sea.<br/> <br />Japan reiterated that Tokyo and Washington had both rejected Beijing's move to set up an air defense zone that includes islands at the heart of a bitter Sino-Japanese feud - despite the fact that three U.S. airlines, acting on government advice, are notifying China of plans to transit the zone.<br/> <br />Washington said over the weekend this did not mean U.S. acceptance of the zone, and last week sent two B-52 bombers into the area without informing China.<br/> <br />Japa
