General Order No. 1 used the 38th parallel to divide surrender responsibilities for Japanese forces in Korea.
The order directed Japanese forces north of the 38th parallel to surrender to the commander of Soviet forces in the Far East. Japanese forces south of that line were ordered to surrender to the commander in chief of U.S. forces in the Far East. The arrangement helped establish the initial division of Korea after Japan’s surrender.
General Order No. 1 was prepared by the U.S. Joint Chiefs of Staff and approved by President Harry Truman on 17 August 1945. Douglas MacArthur issued it after the surrender, and Japanese Imperial General Headquarters transmitted it to Japanese forces on 2 September.
The order concerned surrender and occupation arrangements, not a permanent peace settlement. Nevertheless, the 38th parallel became the practical boundary between Soviet- and American-administered zones. After later political developments, it became the border between North Korea and South Korea.