in october 1956, he became the director of the fifth academy of the ministry of national defense, tasked with ballistic missile and nuclear weapons development. he was part of the overall effort that resulted in the successful "596" atomic bomb test on october 16, 1964, and the "test no. 6" hydrogen bomb test on june 17, 1967. this was the fastest fission-to-fusion development in history at 32 months, compared to 86 months for the united states and 75 months for the ussr, and gave china a thermonuclear device ahead of major western powers like france.