It's 10 p.m. in New York. Virginia A. Kamsky is dashing back from a dinner engagement to check the telex machine in her apartment so she can get back to her colleagues in Beijing before they go out to lunch.

One of the colleagues she's likely to be in touch with is Sidney Rittenberg. He is one of China's oldest foreign experts and a man who spent 16 years in prison on charges of being an American spy.Ms. Kamsky is no less unusual. The 34-year-old Princeton alumna's firm, Kamsky Associates Inc., has reportedly put together business deals in China valued at over $1 billion since she left Chase Manhattan Bank in September 1980 to form the company.

She also, as a rule, hired only women for her firm - until she met Mr. Rittenberg.

Ms. Kamsky, who began studying Chinese when she was 11 years old, owns 60 percent of the company. New York-based American International Group, one of the world's largest insurance companies, owns the other 40 percent.

The biggest deal she has put together so far was a $175 million real estate project in Shanghai for Atlanta-based John Portman & Associates. Her clients are mainly Fortune 500 companies from a broad range of industries, including power generation, aerospace, paper and food, although Ms. Kamsky declines to identify her client list publicly.

The 66-year-old Mr. Rittenberg first went to China with the U.S. Army in 1945.

After the war, he stayed on to work with a United Nations relief agency. He then met Mao Tse-tung and Chou En-lai, who persuaded him to remain in the communist-controlled territories and work on their English-language programs.

As the Cold War intensified, however, Russian officials in China accused him of being an American spy - a charge that eventually resulted in him spending six years in solitary confinement in a Chinese prison.

After his release in 1955, he went back to his old job with Radio Beijing, but the spy charges were revived during China's tumultuous Cultural Revolution and he spent another 10 years in solitary confinement.

I can't really recommend it, he commented drolly during a telephone interview from Beijing, except that it was good for my Chinese because I got to read a lot.

After his release from prison the second time, Mr. Rittenberg eventually became head of Computerland Corp.'s Beijing office before establishing his own consulting firm - called Index China - in the Chinese capital in 1985.

The merger of his company with Kamsky Associates caught the attention of Henry Kissinger. At a business seminar in Los Angeles last December, the former secretary of state congratulated Mr. Rittenberg on being the first man ever hired by the 34-year-old Ms. Kamsky, who is president and chief executive of her firm.

Mr. Kissinger wasn't quite correct.

Years ago we had a male driver, says Ms. Kamsky, who has some 40 women - mostly in their 20s and 30s - on her staff at present. Pointing out that it's very important to have an efficient driver in China to pick up clients at the airport, Ms. Kamsky adds that she also had a man on the professional staff in the early 1980s until he left to go back to graduate school.

You find me a competent man and I'll hire him, she joked during an interview at her office in lower Manhattan.

But when she got together with Mr. Rittenberg and his wife Yulin for lunch last year, there was instant chemistry.

It struck both Ginny, my wife and myself that we complemented each other in a very special way, Mr. Rittenberg says. The whole world changed. It was really electric.

Besides a deep and abiding interest in China, Mr. Rittenberg and Ms. Kamsky share a similar business philosophy. We like to get things built, Mr. Rittenberg says. It's not much fun (just) to do a study. If a company is versatile, we should be able to find something it can benefit from.

Or as Ms. Kamsky puts it: Your work is just beginning when you sign the contract. Although Kamsky Associates represents some clients who are interested only in exporting to China, most of them end up convinced that it's best to go for a joint venture or some form of technology transfer agreement.

You've got to have a long-term perspective in that market, she says. That philosophy is reflected in the long-term contracts Ms. Kamsky signs with her clients - the shortest is for three years.

Ms. Kamsky gives priority to projects in those areas that the Chinese have set as their own economic priorities: transportation, energy, telecommunications, mining and construction. Another priority for the Chinese is any kind of venture that will help China boost its exports, she said.

As a result, her company has become involved in countertrade, three-way deals and offset business.

U.S. companies are at a disadvantage against their European and Japanese competitors who enjoy much more substantial trade finance assistance from their governments. However, the weaker dollar has been a big boost to U.S. companies.

I'm not used to being told that our prices are cheaper, said Ms. Kamsky.

It will be tough for the United States to replace Japan as China's leading trade partner, she said, but it's going to be much closer than ever before.

Mr. Rittenberg shares her optimism about the prospects for U.S. companies.

We're not as good (as the Japanese) at doing things that the Chinese can

absorb, but we're learning, he said. And as we develop things like countertrade, trilateral trade and leasing, the outlook is going to be very good.