The sixth cycle since the Yenan movements of the early 1940s began in 1962, accelerated in mid-1964 and wound down in 1965. It took place at a time of economic recovery and growing confidence on the part of both radicals and conservatives and yet in an increasingly unfavourable international climate. During this period, Sino-Soviet polemics became extremely fierce and the United States threatened China far more seriously than at any time since the Korean War. To what extent would intensified American and Soviet hostility modify both radical and conservative policies?