China and the Soviet Union have concluded their first round of political consultations in three years without any sign of progress in untangling the strategic issues that divide them, according to diplomats here.

But the twice-weekly talks that started here Oct. 5 appear to have taken some of the sting out of the 20-year Communist rivalry, diplomats said, improving the atmosphere for expanded contacts in the commercial and cultural realm.

One tangible outgrowth of the six formal sessions is an agreement to exchange sports teams -- five from each side next year -- for the first time since the early 1960s, according to a well-informed European envoy.

Trade and educational exchanges as well as the larger strategic questions are expected to be discussed at the second round of talks, to be held in Moscow later this year. No date has been set for the next meeting.

"You can't expect anything to happen substantively in an unfriendly atmosphere," explained a diplomat. "Talks like this help to melt the ice."

If they defrosted relations, the recent talks reportedly left untouched the glacier of strategic issues that have turned the two Communist powers into mortal enemies and alternately pushed each closer to Washington for leverage.

Diplomats say any fundamental improvement in Sino-Soviet relations would only come after tortuous and delicate negotiations that could backfire.

Peking has demanded as a condition for normalized relations the withdrawal of Soviet troops from Afghanistan, Outer Mongolia and the Sino-Soviet border and an end to Russian support for Vietnamese forces in Cambodia.

At the Peking talks, Vice Foreign Minister Qian Qichen reportedly asked the Soviet side to ease at least one of those four security threats as a sign of good will.

But Deputy Foreign Minister Leonid Ilyichev, who headed the Soviet delegation, replied that Moscow's relations with third countries are inappropriate topics for Sino-Soviet consultations, according to diplomats.

Instead, Ilyichev urged the Chinese to shelve specific complaints until the two sides have agreed on general principles to guide their relationship, diplomats said.

Ilyichev reportedly cited the example of Sino-American normalization in 1979, when Peking and Washington agreed to certain principles as a basis for relations while leaving the divisive Taiwan issue unresolved.

Disagreement over which should come first -- Peking's security concerns or Moscow's interest in general precepts -- has stymied Sino-Soviet talks for years.

Yet the two sides find the timing right to resume a diplomatic dialogue last postponed by China in 1979 after Soviet troops invaded Afghanistan. Seeking to break out of its diplomatic isolation, Moscow has been trying for months to get the Chinese back to the negotiating table.

Chinese leaders believe better relations with Moscow could reduce tensions along China's hostile borders, which distract the nation and draw away its resources from the pressing task of economic modernization.

The Soviet Union also has become a more attractive trading partner since Peking decided on a policy of rehabilitating China's obsolete factories instead of building new ones with the latest equipment from the West. The outdated Soviet machinery is much cheaper and is adequate for the limited industrial modernization effort, diplomats said.

"Peking has found it has some things in common with another big Communist country even if it threatens China's security," said a senior Asian envoy.

Having identified reasons for talking, neither side expects or wants quick solutions, according to diplomats.

The Soviet side reportedly is concerned that its China opening will be seen by the East European Bloc nations as a license to move closer to independent Peking, which is something they are eager to do.

Peking, in turn, wants to do nothing precipitous that would alarm the United States, Western Europe or Japan, from whom it still hopes to obtain advanced technology in certain areas, such as energy production.