The 1969 Party Constitution (adopted by the 9th Congress) introduced the post of a single vice-chairman, in order to give more authority to Lin Biao as Mao's successor. The 1973 Constitution (adopted by the 10th Congress) re-introduced the collective vice-chairmanship. In 1976, Hua Guofeng was named First Vice-chairman of the Central Committee, a post previously held unofficially by Liu Shaoqi from 1956 to 1966; Zhou Enlai from 1973 to 1975; and Deng Xiaoping in 1975 in the capacity of "Vice-Chairman in charge of the day-to-day work of the Central Committee".