Operation Blacklist Forty was the codename for the United States occupation of Korea between 1945 and 1948. Following the end of World War II, U.S. forces landed in South Korea, accepting the surrender of the Japanese, and with the help of the Soviet Union which occupied North Korea, creating an independent and unified Korean government. However, their relationship became a bumpy road which eventually resulted in the Korean War, that still plays out today. The United State The United State Army Military Government in Korea was the official ruling body of the southern half of the Korean Peninsula from September 8, 1945 to August 15, 1948. In the middle of this political and social upheaval, a few American soldiers held America's ground on the 38th parallel, while the world's super-powers considered dividing up the country.