Gorbachev Leaves Tokyo, and Kaifu Says He Wants to Visit Moscow in Near Future : Diplomacy: Japan’s premier feels he won an ‘extremely significant’ point in dispute over four islands. The Soviet leader flies to South Korea.

TOKYO â€”  Japanese officials suggested Friday that Soviet President Mikhail S. Gorbachev’s visit here had opened the door to some economic aid from Japan, and Prime Minister Toshiki Kaifu declared that he wants to visit the Soviet Union as soon as possible.

Diplomats said the trip might be made in August or September after an advance visit to Moscow by Foreign Minister Taro Nakayama following the London economic summit of seven advanced industrialized democracies July 15-17.

Gorbachev wound up his four-day visit with a whirlwind tour of Kyoto, Osaka and Nagasaki.

“I would like to emphasize . . . once more my adherence to the idea of a nuclear-free world, step by step, together with the other nuclear powers,� Gorbachev said after laying a wreath in Nagasaki’s Peace Memorial Park, where the world’s second nuclear bomb attack occurred.

More than 70,000 people died when an American B-29 dropped the bomb on Aug. 9, 1945, which also was the day on which the Soviet Union broke a nonaggression treaty and declared war on Japan. Six days later, the Japanese surrendered, ending World War II.

Gorbachev, who became the first head of state ever to visit the Nagasaki bomb site, later flew on to Cheju Island in South Korea to meet with South Korean President Roh Tae Woo.

Kaifu described as “extremely significant� an agreement he won from Gorbachev to specify, by name, the four islands the Soviets seized at the end of World War II and recognize that the dispute over their ownership must be resolved in order to conclude a peace treaty. Previously, no Soviet leader had been willing to go beyond a vague reference to “all problems� when referring to peace treaty negotiations.

The new agreement, Japanese diplomats said, produced “a change of mood� in Japan.

“We reached a starting point from which to aim at our goal. A process of confidence-building is about to begin,� one diplomat said.

With Gorbachev refusing to acknowledge Japan’s sovereignty over the islands and Kaifu, in turn, withholding any promise of economic aid, both Gorbachev and Japanese officials acknowledged that the results fell short of a “breakthrough� in Japanese-Soviet relations.

But Foreign Minister Nakayama said that “new arguments� in favor of economic assistance “will emerge as a result of these meetings.�

Another Foreign Ministry official, speaking not for attribution, said that Gorbachev’s visit at least had opened the door “for economic relations to expand.� He mentioned private deals “in which the (Japanese) government is involved� as a possibility.

This official emphasized, however, that full-fledged aid would not be given until “an outlook for a peace treaty to be signed comes into view.�

“For large-scale economic assistance to take place, we need to establish a stable political basis for our relations with the Soviet Union. And for a stable basis, we need to conclude a peace treaty,� the diplomat said.

Vice Finance Minister Masami Kogayu told Japanese reporters that Tokyo will proceed with economic assistance to Moscow in line with progress in the territorial dispute.

Japan rejected Gorbachev’s appeals for Soviet, Japanese and American naval disarmament in the Pacific and plans to ignore the Soviet leader’s proposal for a five-nation summit meeting to discuss Asian security, the diplomats said.

“I don’t think the United States has anything to worry about� as a result of the Gorbachev visit, one of the diplomats said. But he added that Japan will agree to discuss “subregional� Asian security issues with the Soviets.

After negotiations that kept Gorbachev up until after 2 a.m. Friday, the Soviet leader decided to have an unscheduled overnight stay on South Korea’s Cheju Island and to meet with Roh this morning. Originally, he had planned to fly home Friday night.