The Great Naktong Offensive was a North Korean military offensive against United Nations and Republic of Korea forces early in the Korean War, taking place from September 1–15, 1950. It was the North Korean People's Army's unsuccessful final bid to break the Pusan Perimeter established by the United Nations Command.
For the first several months of the war, the North Korean Army successfully defeated and pushed back the United Nations (UN) forces south at each encounter. However, by August the UN troops (which were composed mostly of troops from the United States (US), United Kingdom (UK) and Republic of Korea (ROK) had been forced into the 140-mile (230 km) Pusan Perimeter on the southeast tip of the Korean peninsula. For the first time, the UN troops formed a continuous line which the North Koreans could neither flank nor overwhelm with superior numbers. North Korean offensives on the perimeter were stalled and by the end of August all momentum was lost. Seeing the danger in a prolonged conflict along the perimeter, the North Koreans sought a massive offensive for September to collapse the UN line.
The North Koreans subsequently planned a simultaneous offensive for their entire army along five axes of the perimeter; and on September 1 intense fighting erupted around the cities of Masan, Kyongju, Taegu, Yongch'on and the Naktong Bulge. What followed was two weeks of extremely brutal fighting as the two sides vied to control the routes into Pusan. Initially successful in some areas, the North Koreans were unable to hold their gains against the numerically and technologically superior UN force. The North Korean army, again stalled at the failure of this offensive, was subsequently destroyed in the UN counterattack at Inchon.