HONG KONG — Last week, when the China-Japan dispute over the detention of the captain of a Chinese fishing trawler was hanging fire, U.S. Vice President Joe Biden said American efforts to improve relations with China must "go through Tokyo" because Japan was vital to the United States.

"We sometimes of late have been too quick to focus on one relationship which is critically important," he said, evidently referring to China and implying that the relationship with Japan had been neglected. Renewed tension with Beijing over disputed islands claimed by both China and Japan has had the effect of moving Japan and the United States closer together.

Last Friday, President Barack Obama and Premier Naoto Kan discussed the maritime issue, which involved islands claimed by both Japan and China, and the two "agreed to consult closely on such issues."