The adopted son of Kang Sheng, the legendary head of the People’s Republic of China’s Ministry of State Security (MSS) Foreign Bureau, Yu, known by the code name PLANESMAN, defected to the United States in November 1986, having supplied information to the Central Intelligence Agency for the previous two
years. Kang had been trained in espionage by the Comintern in the Soviet Union before World War II and devoted his career to foreign intelligence operations. An expert calligrapher, reputed to use both hands, he brought up Yu as his own son, a member of Beijing’s elite.
Although never disclosed publicly, Yu was responsible for compromising Bernard Boursicot, a French Foreign Service officer who had been caught in a bizarre honeytrap in Beijing when posted to the French embassy in 1964 at the age of 20, forming a relationship with an actor, a male impersonator who later claimed to have borne him a child. When Yu identified Boursicot, the Frenchman was placed under surveillance by the Direction de la Surveillance du Territoire and was found to be living with his son and the actor, who turned out to be a man. Boursicot, whose strange story was to become the subject of a book, a play, and a movie, was sentenced to six years’ imprisonment, but was released after having served four years. Yu also provided the information leading to the arrest of Larry Wu-Tai Chin, who provided classified information from the CIA to China for more than three decades.