North Korean Onslaught: UN Stand at Pusan August–September 1950

In the first volume in this series on the Korean War, North Korea Invades the South, North Korean ground forces, armour and artillery crossed the 38th Parallel, and, in blitzkrieg style, roll back US and South Korean forces down the Korean peninsula.Despite the United States and South Korea committing army, air force and navy units,supported by forces from Australia, Britain, New Zealand, France and Canada, by 31 July eleven North Korean divisions were concentrated in a disconnected line from Chŏnju to Yŏngdong.

Along the south coast, the North Koreans pushed eastwards towards Masan. To the east and centre of the peninsula, they closed in on Kimch’ŏn and the Naktong River line. On the east coast, three North Korean divisions secured the Yŏngdŏk–P’ohang axis, placing them within mortar range of the UN Yŏnil Airfield.

Reeling back, the UN forces desperately defended the 140-mile line lodgement area that incorporated the port of Pusan (now Busan). Supreme commander of the UN forces, General Douglas MacArthur, had his back to the sea, facing thirteen enemy infantry divisions, two new tank brigades and an armoured division.

On 1 September, North Korean forces launched their strongest offensive to date, and in the first two weeks of the month American casualties were the heaviest of the war. Of particular concern to the commander of the US Eighth Army, Lieutenant General Walton Walker, was the danger of losing the town of Taegu in the centre. The resultant loss of the strategic Taegu–Pusan railway would be catastrophic.

MacArthur and Washington were running out of options, but the Pusan Perimeter had to be defended at all costs.