TOKYO -- Soviet President Mikhail S. Gorbachev and Japanese Prime Minister Toshiki Kaifu ended 12 hours of summit talks early today without the "breakthrough" both had vowed to achieve in a territorial dispute that has stunted their countries' relations for four decades.
Instead, they agreed to "accelerate" negotiations on the future of four small, flinty northern islands that Josef V. Stalin's forces seized in August 1945 as Japan surrendered at the end of World War II. The dispute has kept the two Far Eastern powers from signing a peace treaty formally ending that war.
Mr. Gorbachev had come here hoping that a breakthrough in relations would lead to massive Japanese investment to invigorate the disintegrating Soviet economy.
"We are yet to have that breakthrough," a weary-looking Mr. Gorbachev told reporters well after midnight at a Japan National Press Club news conference that was delayed for more than seven hours while the two leaders repeatedly extended their talks.
Mr. Kaifu, looking equally tired but still able to force frequent smiles during an early-morning news conference at his official residence, came under repeated pressure from Japanese reporters to say what he could point to as achievements on the territorial issue during the three-day summit.
He pointed out that all four disputed islands -- Iturup (Etorofu), Kunashir, Shikotan-to and the Habomai islets -- are for the first time listed by name in the two leaders' 15-page communique, something the Soviets had resisted for more than 40 years.
Refusing to put into words the disappointment that showed on his own face and on those of many other Japanese diplomats, a Foreign Ministry briefer dutifully described the outcome as "a step forward in the long and complex process of our relations with the Soviet Union."
Mr. Gorbachev made history by arriving Tuesday in Tokyo, something no other Russian or Soviet leader had done in the often stormy and sometimes bloody 150 years of official relations between the two Northeast Asian neighbors.
But the summit meetings themselves will be remembered for their length rather than for their productivity.
"Perhaps another entry in the Guinness Book of World Records," Mr. Gorbachev quipped in a reference to the 12 hours of meetings spread over three days, about 80 percent of which were said to have dealt with the four small islands, part of the Kuril Islands group.
Instead of a breakthrough, he and Mr. Kaifu ended their encounter with a midnight signing ceremony dedicated to the communique and to 14 previously prepared documents that add up to a few more cautious steps in warming their countries' relations.
The agreements double the number of government-sponsored students sent to each country from 20 to 40, provide for Japan to send teams of experts to help Mr. Gorbachev's government move the Soviet Union toward a market economy, codify Japan's help in dealing with effects of the Chernobyl nuclear power plant disaster, establish a center for modern Japanese studies in Moscow and expand working-level diplomatic contacts.
Today Mr. Gorbachev will visit Kyoto and Nagasaki before heading to South Korea.