Because the Chesapeake flight is back, I wondered if anons had missed something or were on the wrong track.

Searched Dboulbe Keystone which let me here >https://www.nationalreview.com/2018/12/china-sea-power-challenges-international-order/

"The national interests of the United States, Japan, and China meet in Okinawa. The island has been essential to the forward deployment of U.S. forces in Asia since World War II. The base is the ""keystone"" of the U.S.–Japan alliance. Our presence signifies America’s guarantee of Japanese security and helps sustain the economy of Japan’s poorest prefecture.

Okinawa is the gateway to mainland Asia for the United States and Japan. It is for the same reason that China views Okinawa as an obstacle. Chinese vessels must pass through the Miyako Strait south of Okinawa to reach the ""blue waters"" of the Philippine Sea and, from there, the “second island chain” encompassing the Mariana Islands, Guam, Palau, and Borneo. (The third island chain includes Hawaii.)"

I'll dig…