Test No. 6

Test No. 6 is the codename for China's first test of a three-staged thermonuclear device and, also its sixth nuclear weapons test. The device was detonated at Lop Nur Test Base, or often dubbed as Lop Nur Nuclear Weapon Test Base, in Malan, Xinjiang, on 17 June 1967. With successful testing of this three-stage thermonuclear device, China became the fourth country to have successfully developed a thermonuclear weapon after the United States, Soviet Union and the United Kingdom. It was dropped from a Hong-6 (Chinese manufactured Tu-16) and was parachute-retarded for an airburst at 2960 meters. The bomb was a three-stage device with a boosted U-235 primary and U-238 pusher. The yield was 3.3 megatons.

It was a fully functional, full-scale, three-stage hydrogen bomb, tested 32 months after China had made its first fission device. China thus produced the shortest fission-to-fusion development known in history. China had received extensive technical help from the Soviet Union to jump-start their nuclear program, but by 1960, the rift between the Soviet Union and China had become so great that the Soviet Union ceased all assistance to China. Thus, the Number 6 test was indeed an independent endeavor, after the induced military and economic sanctions enacted by the superpowers at the time, the United States and the Soviet Union.

Nevertheless, a comparison of other fission-to-fusion timespans may be instructive. The time between the U.S.'s first atomic test and its first hydrogen bomb test was 86 months, for the USSR it was 75 months, for the UK 66 months and later for France, 105 months.

The goal of China was to produce a thermonuclear device of at least a megaton in yield that could be dropped by an aircraft or carried by a ballistic missile. Several explosions to test thermonuclear weapon designs, characteristics and yield boosting preceded the thermonuclear test.