
Timetoast.com
By September 1950 the North Korean Peoples Army (KPA) reached their farthest point of advance in South Korea.
Although the KPA strength had been nearly cut in half and it lacked sufficient armor and supplies, the North Koreans reduced the area under control by United Nations forces to a 5,000-square-mile rectangle centered on the critical southeastern port of Pusan (Busan).
https://www.historynet.com/korean-war-battles-of-the-bowling-alley.htm