Humanities › History & Culture The Pusan Perimeter and Invasion of Incheon Share Flipboard Email Print American armed forces firing at North Koreans. US Army/Wikimedia Commons/Public Domain History & Culture Asian History East Asia Basics Figures & Events Southeast Asia South Asia Middle East Central Asia Asian Wars and Battles American History African American History African History Ancient History and Culture European History Genealogy Inventions Latin American History Medieval & Renaissance History Military History The 20th Century Women's History View More By Kallie Szczepanski History Expert Ph.D., History, Boston University J.D., University of Washington School of Law B.A., History, Western Washington University Dr. Kallie Szczepanski is a history teacher specializing in Asian history and culture. She has taught at the high school and university levels in the U.S. and South Korea. our editorial process Kallie Szczepanski Updated March 10, 2018 On June 25, 1950, North Korea launched a surprise attack on South Korea across the 38th parallel. With lightning speed, the North Korean army overran South Korean and U.S. positions, driving down the peninsula. 01 of 02 Pusan Perimeter and Invasion of Incheon South Korean and US forces were pinned down in the southeast corner of the peninsula, in blue. Red arrows show North Korea's advance. UN troops attacked behind enemy lines at Incheon, indicated by the blue arrow. Kallie Szczepanski After only about a month of bloody fighting, South Korea and its United Nations allies found themselves pinned down in a small corner of land around the city of Pusan (now spelled Busan), on the southeast coast of the peninsula. Marked in blue on the map, this area was the last stand for these allied forces. Throughout August and the first half of September 1950, the allies fought desperately with their backs against the sea. The war seemed to have reached a stalemate, with South Korea at an extreme disadvantage. Turning Point at the Invasion of Incheon On September 15, however, U.S. Marines made a surprise counter-attack well behind North Korean lines, at the coastal city of Incheon in northwestern South Korea indicated by the blue arrow on the map. This attack became known as the Invasion of Incheon, a turning point in the South Korean army's power against their North Korean invaders. The Invasion of Incheon distracted the invading North Korean armies, allowing the South Korean troops to break out of the Pusan Perimeter, and begin to push the North Koreans back into their own country, turning the tide of the Korean War. With the help of United Nation forces, South Korea secured the Gimpo Airfield, won the Battle of the Busan Perimeter, retook Seoul, captured Yosu, and ultimately crossed the 38th Parallel into North Korea. 02 of 02 Temporary Victory for South Korea Once the South Korean armies began capturing cities north of the 38th Parallel, their General MacArthur demanded North Koreans surrender, but the North Korean armies murdered Americans and South Koreans at Taejon and civilians in Seoul in response. South Korea pressed on, but in doing so stirred North Korea's powerful ally China into battle. From October 1950 to February 1951, China launched the First Phase offensive and recaptured Seoul for North Korea even as the United Nations declared a ceasefire. Because of this conflict and the resulting fallout after which, the war would rage on another two years before its conclusion with the negotiation of an armistice between 1952 and 1953, wherein the opposing forces negotiated reparations for prisoners of war taken during the bloody conflict.