China's land border with Vietnam terminates at the shore of this sea, so of course in that area the "territorial waters" don't extend so far. It's the same as e

China's land border with Vietnam terminates at the shore of this sea, so of course in that area the "territorial waters" don't extend so far. It's the same as e.g. Canadian waters located right next to USA. In addition, China and Philippines are separated by about 400 miles at their closest points, so that would curtail a 230 mile perimeter for at least one of those nations.