Medium tank to manufacture a well-balanced medium tank in very large numbers - around 57,000 T-34s and 49,000 M4 Sherman tanks were built during the war period. During and after World War II, the roles of light tanks were gradually taken over by less-expensive armoured cars and specialised reconnaissance vehicles. Heavy tanks, having shown their limitations in combat, experienced a limited post-war arms race of progressively more heavily armed and armoured designs. With the rise of more sophisticated anti-tank missile weapons, to which heavy tanks had demonstrated high vulnerability, these too were eventually phased out. With advances in technology, aspects such as
US signals intelligence in the Cold War evidence that a significant event was imminent, much less a North Korean invasion of the South. In 1952, when personnel levels and a more static war allowed some retrospective analysis, AFSA reviewed unprocessed intercept from the June 1950 period. Analysts could not find any message which would have given advance warning of the North Korean invasion. One of the earliest, if not the earliest, messages relating to the war, dated June 27 but not translated until October, referred to division level movement by North Korean forces. UN forces in the Korean War had an assortment of SIGINT units from the