Mikhail S. Gorbachev began the first visit by a Soviet head of state to Japan Tuesday by seeking a reconciliation that would lead to Japanese help for the crumbling Soviet economy.

With little negotiating room on a thorny territorial dispute, Gorbachev offered conciliatory gestures aimed at putting historical resentments to rest.In his only public remarks Tuesday, the Soviet president expressed condolences for the deaths of tens of thousands of Japanese prisoners of war in Siberian labor camps more than 40 year years ago, although he stopped short of a formal apology.

"Giving the tribute of respect to the memory of the war dead from both sides and expressing condolences to the families of the prisoners of war who died abroad, we say it is time to do everything we can so that our peoples and states will never again drift into the disaster of enmity," Gorbachev said in a toast at a banquet given by Emperor Akihito Tuesday evening.

The emperor, in turn, said he was "happy that there is growing enthusiasm in every segment of both countries for deepening mutual understanding and trust and building up a new neighborly relationship."

In their first summit, Gorbachev and Prime Minister Toshiki Kaifu spent more than three hours discussing issues including the territorial dispute that prevented their two nations from ever signing a World War II peace treaty.

After the talks, officials said the two leaders had agreed not to disclose any details of their discussions on the disputed Kuril Islands off northern Japan.

However, a Soviet official floated a proposal for use of one of the disputed islands: the construction of a nuclear power plant to be run jointly by the Soviet Union and Japan.

A Japanese Foreign Ministry official, who spoke on condition of anonymity, said Kaifu accepted an invitation from Gorbachev to visit Moscow.

"We want to settle past matters and start and build new, friendly relations," a Japanese Foreign Ministry official quoted Kaifu as saying.

The Soviet president's chief spokesman, Vitaly N. Ig-natenko, said the Soviet leader pointed to Moscow's improved ties with Europe and the United States and contrasted them with chilly Moscow-Tokyo relations.

In some areas of the Japanese-Soviet relationship, "life can hardly be seen," Ignatenko quoted Gorbachev as saying.

The two sides have completed most of 14 minor agreements expected on trade and cooperation in various fields.

Ignatenko said Gorbachev would make "concrete proposals" in meetings on Wednesday.