Here are four things the world should note about China’s bold move.

First, let’s call it what it is. Beijing has declared an air control zone, not a defense zone. Normally, in air defense zones countries seek to identify aircraft in that are close to or approaching national territory. Think of the analogue with territorial waters. Obviously, airplanes that fly over national territory, such as commercial airliners, must identify themselves. But they are also presumed to be engaging in innocent passage, just like cargo or passenger ships on the seas.

What China has done is very different. In claiming most of the East China Sea as a control zone—within 80 miles of Japanese territory at its closest point—the country is demanding that airplanes flying hundreds of miles from China’s actual territory must now identify themselves and declare their flight paths, even if they are not going to China. This is not defense: It is a not-so-subtle form of much wider control. While Chinese spokespersons say the move does not affect the freedom of international flights, the reality is much different. There is no basis for such a wide zone, other than to get foreign countries to accept that they are passing through what are, in essence, Chinese-controlled skies. And if a foreign plane doesn’t provide Chinese authorities the information they demand? China will then take “defensive emergency measures,” according to the government—in other words, shadow, threaten or shoot down foreign planes.

Second, Beijing’s announcement is a direct challenge to Japan and Korea, since China’s new control zone overlaps those of both Tokyo and Seoul.