By the time 3 RAR arrived in Pusan on 28 September, the KPA was in retreat. Under UN Supreme Commander, General Douglas MacArthur, UN forces conducting a successful amphibious assault at Inchon and breakout from the Pusan Perimeter on the southern tip of the Korean peninsula. A steady advance began, driving the North Koreans northwards towards the 38th Parallel. In October the UN forces began their advance into North Korea and 3 RAR was involved in its first major action near Pyongyang.