Battle of Pusan Perimeter.

North Korean forces invaded South Korea on June 25, 1950, advancing southward quickly despite U.S. military intervention. After defeats at Osan, the Kum River, and Taejon, the U.S. Eighth Army established in late July a defensive position in the southeast corner of the peninsula. A rectangular area, the Pusan Perimeter was about eighty miles from north to south along the Naktong River and fifty miles east to west to just north of Yongdok on the Sea of Japan. Defending it was the U.S. Twenty-fourth and Twenty-fifth Infantry and First Cavalry Divisions together with the First, Third, Sixth, Eighth, and Capital Divisions of the Republic of Korea (ROK), guided by General Walton Walker.