The proximity of Taiwan to its principal adversary, the People’s Republic of China, has provided the National
Security Bureau (NSB) with a large target since it was established in March 1955. Staffed by veterans of the Kuomintang, the Nationalist Chinese NSB had plenty of experience in combating Mao’s Communists and collaborated closely with the Central Intelligence Agency station in Taiwan. Together, the CIA and NSB managed an overflight program of U-2 aircraft to monitor missile and atomic weapon tests, and a balloon project designed to drop propaganda leaflets across the Taiwan Strait.