The PRC has just announced its new East China Sea Air Defense Identification Zone. An ADIZ is something that any modern nation does as it exercises measures to increase the safety of its territory. An ADIZ is a device, well published, that allows a nation to identify approaching aircraft with enough warning time to be able to react should that aircraft have nefarious intentions.
As can be seen, though, the PRC’s new ADIZ carefully includes the Senkaku Islands, which are Japanese territory (although the Republic of China also claims them as the Tiaoyutai Islands). What makes the PRC’s move especially…suspect…is its ongoing grab of the entire East China Sea, claiming this mostly international water as PRC sovereign territory. This is a direct, deliberate challenge to Japan and to the US, who is a close ally of Japan, and it’s intended to be so, as the US fades from the global stage.
As an aside, this move also is a direct, deliberate challenge to the RoC, and to the US, who is a close ally of the RoC. Recall that the PRC considers the RoC as sovereign PRC territory, too, and that the US, to our shame, long ago supported the ejection of China from the UN Security Council in favor of the PRC.
By contrast, here’s the US ADIZ: