After months as a spurned suitor, the Soviet Union is hoping that exploratory talks in Peking will help pave the way for ''normalization,'' a gradual improvement in relations with the Chinese.
On the main substantive issues dividing the communist giants, neither side has visibly signaled a readiness to compromise. The Chinese still insist that Moscow demonstrate goodwill in deed, not just word.
The suggestion is that the Soviets should, for instance, trim their troop strength on the Chinese border, or withdraw from Afghanistan, or pressure their Vietnamese allies to pull out of Kampuchea. If the Soviets are planning to oblige, they have not yet shown their hand.
Foreign diplomats in both Moscow and Peking are assuming that major progress in healing the two-decade-old Sino-Soviet rift will not come quickly.
Yet the overall climate of relations has recently thawed a bit, and the Soviets are trying hard to encourage this trend.
The key atmospheric change has come from Peking. After shrugging off various Soviet overtures in the past year or so, the Chinese have agreed to an official visit by Soviet Deputy Foreign Minister Leonid Ilyichov for exploratory talks on Sino-Soviet relations.
A Chinese statement Oct. 4 said Mr. Ilyichov had arrived and would meet Chinese Vice-Foreign Minister Qian Qichen.
Initially, the Chinese had told diplomats Mr. Ilyichov would come as a guest of the Soviet ambassador, rather than on an official invitation from Peking. This has been the rule for Soviet visits since China broke off the last round of talks in 1979.
The Chinese revealed the shift only on Sept. 30, in remarks to foreign journalists at a reception in Moscow. But Soviet diplomats in Peking are understood to have told colleagues of the change before Soviet President Brezhnev's latest public statement on relations with China.
In remarks clearly intended to set the stage for the Ilyichov mission to Peking, Mr. Brezhnev omitted any hint of criticism of Chinese policy. He said: ''As regards Asia, we would deem it very important to achieve a normalization, a gradual improvement of relations between the USSR and the People's Republic of China on a basis that I would describe as that of common sense, mutual respect, and mutual advantage.''
The speech, delivered in the capital of Soviet Azerbaijan, lasted some 40 minutes and touched on various points of domestic and foreign policy. At an open political lecture in Moscow shortly afterward, a party official said the remarks on China were the most important part of the Brezhnev talk.
In the run-up to Mr. Ilyichov's discussions in Peking, the Soviets have moved to sweeten the atmosphere for his mission.
For instance, Mr. Ilyichov himself represented the Soviets at the Chinese national day reception here Sept. 30.
The same day, as if to underscore Soviet readiness for truly normal relations with the Chinese, the official news agency Tass broke with recent practice to carry a routine, and politically neutral, news item from Peking. It reported China's plans to upgrade various industrial enterprises.
On Oct. 1, Soviet television broadcast a Chinese-made documentary film for the first time in many years. Tass recorded the fact, lest anyone miss the signal.
The talks in Peking signal that both the Chinese and the Soviets are attempting at least an atmospheric improvement in relations - particularly, foreign diplomats assume, in light of each country's recently strained ties with the United States.
But on issues of substance both sides seem more cautious. Each appears to see the talks partly as an occasion to feel out the ultimate intentions of the other.
Soviet officials suggest Moscow would like the Peking meeting to encourage an improvement in the less controversial areas of Sino-Soviet relations, such as cultural and commercial ties, while laying the groundwork for talks on thornier issues like the countries' border dispute.