China exploded its first atomic bomb at the Lop Nur test site in Xinjiang on October 16, 1964, and became the fifth country with nuclear weapons, after the United States, the Soviet Union, Britain and France. The device was a uranium-based implosion weapon, and the test was a full success. The same day the government issued a statement saying it would never be the first to use nuclear weapons, a pledge the country has repeated since.
The programme had been decided a decade earlier. In the 1950s the leadership concluded that a country in China's position could not leave its security to the goodwill of others, and that without the bomb it would always be subject to threats from the powers that had one. Work began in 1955, and it drew on scientists who had been trained abroad and had come back, including Qian Sanqiang and Deng Jiaxian, who ran the technical side. The project was kept secret for years, and the first test caught most of the outside world by surprise.
The timing was deliberate. It came four years after the Soviet Union had withdrawn its technical assistance, and the bomb was built without outside help after that, which made the point the leadership wanted made: that the weapon was China's own. The uranium enrichment and the weapon design were done at home, and the test came a little over a year after the limited test ban treaty of 1963, which China had not signed, arguing that the treaty was an attempt by the existing nuclear powers to keep the weapon for themselves.
It changed the standing. A hydrogen bomb followed. It came in 1967. A satellite went up in 1970. The three together are the foundation of what the country calls its two bombs and one satellite, the badge of its rise to a major power. The test site at Lop Nur became the centre of a programme that developed into a modern force, and the pledge of no first use, made on the day of the first test, remains the stated policy.