"They were the first group of US students who were in China for long-term study since 1949," the veteran diplomat says.

"There had been the occasional delegations of US scientists to China after President Nixon's visit in February 1972, but nothing serious. Things happening in those years precluded more meaningful engagement: as Nixon stepped down in 1974 in the aftermath of the Watergate scandal, China was still knee deep in the cultural revolution," he says, referring to the political movement from 1967 to 1977 at the beginning of which China's annual college entrance examination was abolished and almost all exchanges with the West ended.

Between 1977 and 1988 Mary Bullock, daughter of a man who grew up in China with his missionary father, was the director of the Committee on Scholarly Communication with the People's Republic of China.

"When the CSCPRC was founded in 1966 there was no agreement with China-China at the time was probably opposed to the idea-only agreement among members of American academia who believed exchanges must resume no matter what," Bullock says.

"They didn't know that the cultural revolution was coming, but they set up this organization with a small group of people and non-government money, if only to be prepared when the time was right."

And finally the time was right. On July 7,1978, barely a month after Thomson arrived in Beijing, a US delegation, led by President Jimmy Carter's science adviser Frank Press, met Chinese counterparts.