"Seoul is the fourth largest metropolitan area in the world — home to 25.6 million people. And it's just 35 miles from North Korea. Then there’s Tokyo. It has 37.8 million people in its greater metropolitan area"

Strange how you fail to mention 50,000 U.S. military personnel stationed in Japan, along with approximately 40,000 dependents of military personnel and another 5,500 American civilians employed there by the United States Department of Defense. Or the 28K+ in S. Korea.