New Soviet leader Mikhail Gorbachev completed another day of back-to-back diplomatic meetings today, impressing a stream of foreign dignitaries with his energy and self-confidence.

In his first days in office, Gorbachev already has met twice as many visiting delegations as his predecessor, the late Konstantin Chernenko.

Gorbachev's meetings with foreign visitors here to attend Chernenko's funeral yesterday revealed more about the style of the new Kremlin leadership than about any change in policy, diplomats said.

But Gorbachev's selection of visitors was also revealing. Today he received a delegation from China, a sign that he intends to follow up on his call Monday for "serious improvement" in relations between the two Communist giants. Last year, at the funeral of former president Yuri Andropov, the Chinese delegation met not with Chernenko, the incoming leader, but with another member of the Politburo.

Gorbachev also met today with Japanese Prime Minister Yasuhiro Nakasone, the first time that the two countries' top leaders have met since 1973 and only the third time in Soviet history.

West German Chancellor Helmut Kohl and French President Francois Mitterrand, after their meetings with Gorbachev this week, reported that he had accepted their invitations to visit their countries, although no dates were set.

But officials in Washington said Gorbachev did not commit himself in response to a letter from President Reagan, delivered by Vice President Bush, that reportedly invited him to a summit meeting there.

Bush said before leaving Moscow late last night, however, that he found "nothing discouraging" in Gorbachev's reaction, and added that their 85-minute meeting in the Kremlin gave him "high hope" for improved U.S.-Soviet relations.

Some western diplomats noted that Gorbachev met on the first day with President Daniel Ortega of Nicaragua and with Ethiopian leader Haile Mariam Mengistu. Last year, Ortega was given less favorable treatment and the Ethiopians were not received at all.

However, the absence of Cuban President Fidel Castro was taken by some here as a sign of Cuban dissatisfaction with Soviet aid to Nicaragua.

Western leaders emerging from their meetings with Gorbachev described him as "firm," "frank," "calm" and possessing a "keen historical awareness."

"He talks very openly. He is a commanding, well-informed, strong man, with a natural authority," Kohl said after their meeting today. "He has an easy charm but, at the same time, can stand up for his interests firmly and coldly."

Few specifics about the meetings were revealed, but, according to western diplomats, Gorbachev stuck closely to recent Soviet policy on international issues. Foreign Minister Andrei Gromyko was present at all the encounters.

Western diplomats said today that Gorbachev, in a joint meeting with leaders of Eastern European countries, rescheduled a Warsaw Pact summit for April in Sofia, Bulgaria. Such a summit was postponed earlier this year because of Chernenko's poor health.

A plenum of the Central Committee is also still expected in April, which will give the new Soviet leader a chance to exert his authority.

"It could be a busy April, but he has already shown he can handle a killing schedule," one western diplomat said.

Among western-allied leaders, Gorbachev met today with Prime Ministers Felipe Gonzalez of Spain and Brian Mulroney of Canada as well as Kohl and Nakasone.

At a short briefing after their meeting, Nakasone said the two had discussed the continuing dispute over the Kurile Islands, which Moscow annexed from Japan after World War II. According to Nakasone, Gorbachev said the Soviet stance on the issue "is not to be changed." But Gorbachev raised hopes for a long-awaited visit to Japan by Gromyko.

The U.S.-Soviet arms talks begun in Geneva this week were a recurrent theme in Gorbachev's meetings with Western European leaders. Gorbachev apparently reiterated the Soviet position that the top priority at the talks is to prevent the spread of weaponry to space.

Gorbachev also met with Mohammed Zia ul-Haq of Pakistan, Babrak Karmal of Afghanistan, Jose Eduardo dos Santos of Angola, Truong Chinh of Vietnam, Ali Nasser Hasani of South Yemen and Samora Machel of Mozambique.

The Chernenko funeral also provided opportunities for bilateral meetings between other government leaders. West Germany's Kohl met Tuesday night with Erich Honecker of East Germany, and later with Premier Wojciech Jaruzelski of Poland and President Gustav Husak of Czechoslovakia.