Nuclear weapon history
Because of strict secrecy it is very difficult to determine the exact size and composition of China's nuclear forces. Several declassified U.S. government reports give historical estimates. The 1984 Defense Intelligence Agency's Defense Estimative Brief estimates the Chinese nuclear stockpile as consisting of between 150 and 160 warheads. A 1993 United States National Security Council report estimated that China's nuclear deterrent force relied on 60 to 70 nuclear armed ballistic missiles. The Defense Intelligence Agency's The Decades Ahead: 1999 - 2020 report estimates the 1999 Nuclear Weapons' Inventory as between 140 and 157. In 2004 the U.S. Department of Defense assessed that China had about 20 intercontinental ballistic missiles capable of targeting the United States. In 2006 a U.S. Defense Intelligence Agency estimate presented to the Senate Armed Services Committee was that "China currently has more than 100 nuclear warheads."
A mock-up of China's first nuclear bomb.
China's first test of a nuclear device took place on October 16, 1964, at the Lop Nur test site. China's last nuclear test was on July 29, 1996. According to the Australian Geological Survey Organization in Canberra, the yield of the 1996 test was 1-5 kilotons. This was China's 22nd underground test and 45th test overall.
China has made significant improvements in its miniaturization techniques since the 1980s. There have been accusations, notably by the Cox Commission, that this was done primarily by covertly acquiring the U.S.'s W88 nuclear warhead design as well as guided ballistic missile technology. Chinese scientists have stated that they have made advances in these areas, but insist that these advances were made without espionage.
Although the total number of nuclear weapons in the Chinese arsenal is unknown, as of 2005 estimates vary from as low as 80 to as high as 2000. In 2004, China stated that "among the nuclear-weapon states, China... possesses the smallest nuclear arsenal," implying China has fewer than the United Kingdom's 200 nuclear weapons. Several non-official sources estimate that China has around 400 nuclear warheads. However U.S. intelligence estimates suggest a much smaller nuclear force than many non-governmental organizations.
China is one of the five "nuclear weapons states" (NWS) under the Nuclear Non-Proliferation Treaty, which China ratified in 1992. China is the only NWS to give a security assurance to non-nuclear-weapon states:
"China undertakes not to use or threaten to use nuclear weapons against non-nuclear-weapon states or nuclear-weapon-free zones at any time or under any circumstances."
Chinese public policy has always been one of the "no first use rule" while maintaining a deterrent retaliatory force targeted for countervalue targets.
2005 white paper
In 2005, the Chinese Foreign Ministry released a white paper stating that the government would not be the first to use nuclear weapons at any time and under any circumstances. In addition, the paper went on to state that this "no first use" policy would remain unchanged in the future and that China would not use or threaten to use nuclear weapons against any non-nuclear-weapon states or nuclear-weapon-free zones.
2010 IISS Military Balance
The following are estimates of China's strategic missile forces from the International Institute of Strategic Studies Military Balance 2010. According to these estimates, China has up to 90 inter-continental range ballistic missiles (66 land-based ICBMs and 24 submarine-based JL-2 SLBMs), not counting MIRV warheads.