During the Korean War over 45,000 Air Guardsmen, in 22 wings and other units, were called into active Federal service. The 136th Fighter-Bomber Wings, Texas ANG, was among the first Air National Guard units to be called. Flying the F-84E Thunderjet, the Texas Guardsmen moved to Japan in May 1951 and, shortly thereafter, became the first Air Guardsmen to enter combat in the Korean War. During the winter and spring of 1951, the Chinese Communist Air Force mounted a major air offensive against the United Nations air forces. The major contested area were the skies over northwestern Korea known as "MIG Alley." The U.S. Air Force retaliated by mounting a counteroffensive aimed at destroying the enemy's aircraft and bases. In June 1951 the 136th's 182d Fighter-Bomber Squadron was given the mission of protecting B-29 flights on bombing missions over North Korea. On June 26, 1951, the pilots of the 182d were escorting four B-29s to an enemy airfield near Yongyu when five MIG-15s attacked the American bombers. Although relatively new to combat, the pilots of the 182d turned back the veteran MIG pilots. During the ensuing dogfight, 1st Lt. Arthur E. Oligher assisted by Capt. Harry Underwood, shot down a MIG-15--the first Air Guard jet "kill." The Air National Guard went on to make an impressive combat flying record. Today's 182d Tactical Fighter Squadron, Texas Air National Guard continues to add to its impressive flying record. The Korean War (1950–53) was a military conflict between the Republic of Korea, supported by the United Nations, and the Democratic People's Republic of Korea and People's Republic of China (PRC), with air support from the Soviet Union. The war began on 25 June 1950 and an armistice was signed on 27 July 1953. The war was a result of the political division of Korea by agreement of the victorious Allies at the conclusion of the Pacific War. The Korean peninsula had been ruled by Japan from 1910 until the end of that war. In 1945, following the surrender of Japan, American administrators divided the peninsula along the 38th parallel, with United States troops occupying the southern part and Soviet troops occupying the northern part after that.[25] The failure to hold free elections throughout the Korean Peninsula in 1948 deepened the division between the two sides, and the North established a Communist government. The 38th Parallel increasingly became a political border between the two Koreas. Although reunification negotiations continued in the months preceding the war, tension intensified. Cross-border skirmishes and raids at the 38th Parallel persisted. The situation escalated into open warfare when North Korean forces invaded South Korea on 25 June 1950.[26] It was the first significant armed conflict of the Cold War.[27] The United Nations, particularly the United States, came to the aid of the South Koreans in repelling the invasion. After early defeats by the North Korean military, when a rapid UN counter-offensive repelled the North Koreans past the 38th Parallel and almost to the Yalu River, the People's Republic of China (PRC) came to the aid of Communist North.[26] With Communist China's entry into the conflict, the fighting took on a more dangerous tone. The rapid Chinese counter-offensive repelled the United Nations forces past the 38th Parallel. The Soviet Union materially aided North Korea and China. The threat of a nuclear world war eventually ceased with an armistice that restored the border between the Koreas near to the 38th Parallel and created the Korean Demilitarized Zone (DMZ), a 2.5-mile (4.0 km) wide buffer zone between the two Koreas. During the war, both North and South Korea were sponsored by external powers, thus facilitating the war's metamorphosis from a civil war to a proxy war between powers involved in the larger Cold War. From a military science perspective, the Korean War combined strategies and tactics of World War I and World War II — swift infantry attacks followed by air bombing raids. The initial mobile campaign transitioned to trench warfare, lasting from July 1951 until the 1953 border stalemate and armistice.