The U.S. has involved itself in the latest flare up of the islands dispute between Japan and China in the East China Sea by flying two unarmed B-52 bombers in the area without informing Beijing.
The U.S. moves comes after China included the islands - known as Senkaku in Japan and Diaoyu in China - in an Air Defense Identification Zone, and warned that it would take military action against airplanes flying in the region without notification.
Meanwhile, Japanese airlines have also defied Beijing and flown through the area without providing China with flight plans.
At stake in the row are fishing rights and access to up to 160B barrels of oil.
When the dispute first flared up a year ago, trade between China and Japan was badly hit, with the latter's car makers suffering in particular.