Despite the outrage stirred up in the Pacific by its nuclear test yesterday, Western nuclear weapons specialists believe China remains committed to a comprehensive nuclear test ban next year.
Like France, China has decided to take the last opportunity to perform more tests before a total ban comes into force, to demonstrate its ability to build smaller multiple warheads for smaller missiles.
The Chinese underground test took place at the Lop Nor site south east of Urumqi in the Xinjiang autonomous region, at 0100 GMT yesterday. It created a small earthquake, measured at 5.6 on the Richter scale, and the explosion was estimated as equivalent to 60,000 tons of TNT - relatively large by test standards.
With 43 tests, China is catching up with Britain, which has conducted 44. France has conducted 192 tests since 1960. Peking says it has conducted relatively few tests - Britain, after all, had substantial technical help from the US in developing its nuclear weapons.
Last week at the disarmament negotiations in Geneva, France agreed to a comprehensive test ban treaty covering all nuclear explosions - including very small ones, which it had previously asked to be excluded on the grounds they were needed to check the safety of nuclear weapons.
China and France are developing miniaturised nuclear warheads, suitable for fitting to missiles to be launched from submarines. China has been developing submarine-launched ballistic missiles and land-based, solid- fuel ballistic missiles, which are safer to store and quicker to launch.
The latest nuclear tests appear to be connected with the development of smaller, solid-fuel missiles, possibly with multiple warheads. The first solid-fuel missile was tested in the 1980s, and more recently China has introduced the "M" family of mobile, land-based missiles. Two mobile missiles, the Dong Feng ("East Wind") -31 and -41, with ranges of 5,000 miles and 7,500 miles, are also under development.
Multiple warheads would be a logical development, although according to the authoritative Nuclear Weapons Databook, the Chinese may be pursuing these technologies "as much to demonstrate their ability to master them as to gain any tangible security improvement".