The last time China set up an air defense identification zone, or ADIZ, was in late 2013, when tensions with Japan had escalated so far, many were speculating if the two nations would not engage in limited warfare. Back then, China set up its first ADIZ in the East China Sea in November 2013 to cover the Diaoyu Islands, which Japan calls the Senkakus. Both countries claim the uninhabited outcrops but Tokyo controls them. The ADIZ triggered a backlash from Japan, South Korea and the US.