By the time 3 RAR arrived in the theatre, the KPA had been broken and were in rapid retreat, with MacArthur's 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. The 27th British Commonwealth Brigade was airlifted from Taegu to Kimpo Airfield north of Seoul on 5 October; however, its vehicles had to move by road, driving , and did not arrive until 9 October. It was subsequently attached to the US 1st Cavalry Division, under the command of Major General Hobart R. Gay. On 16 October the brigade took over from the US 7th Cavalry Regiment as the vanguard of the UN advance into North Korea, its axis intended to take it through Kaesong, Kumchon and Hungsu-ri to Sariwon, then through Hwangju to the North Korean capital of Pyongyang. Although the KPA had suffered heavily in the preceding weeks, they continued to resist strongly, while a lack of accurate maps and the narrowness of the roads made rapid movement difficult for the advancing UN forces. During this time 3 RAR had a platoon of American M4 Sherman tanks attached and a battery of field guns in direct support.