South Korea says it will expand its air defense zone over the Yellow Sea, as of 15 December.  The South Korean zone will incorporate airspace that was claimed by China last month, and has been in the Air Defense Zone of Japan for years.

It also covers the air above a submerged rock that lies about four and a half meters below the ocean’s surface, claimed by both Beijing and Seoul.  International maritime law stipulates that a submerged rock outside of a nation's territorial sea cannot be claimed as territory by any nation, but that’s not stopping anyone these days.

South Korea built a nautical research station on the rock in 2003, giving it effective control. It lies southwest of the Korean peninsula, about 105 miles from the nearest South Korean land territory and 180 miles from the closest Chinese land.  Prior to that, South Korea put a nautical warning beacon on it in 1987.  You’d think China would have been grateful for that, because it crashed a ship into the rock in 1963.

Although this ratchets up tension between Seoul and Beijing, Tokyo isn’t terribly concerned because South Korea made it clear that the new Air Defense Zone wouldn't infringe on the freedom of travel by commercial planes.

“Unlike the Chinese action, we reached an understanding beforehand, so this would not create an immediate problem for Japan-Korea relations,” said Japanese spokesman Hikariko Ono.