Russia and Japan are due to meet over a territorial dispute that has prevented the two countries from signing a peace treaty after World War II.
Japanese Prime Minister Shinzo Abe will host Vladimir Putin on the Russian leader's first official visit to a G-7 country since Russia's 2014 annexation of Crimea at a hot spring in his ancestral city of Nagato on Thursday. There are hopes of achieving a breakthrough over the territory off Japan's northern coast seized by Soviet troops in 1945.
The four islands are known as the Southern Kurils in Russia and the Northern Territories in Japan, and the dispute has been a thorn in relations for more than seven decades.
Despite months of preparation, the outlook is not good, with both sides recently damping down expectations of major progress.
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"I want to go into this summit with determination to end the issue in my generation," Abe told former residents of the islands earlier this week, suggesting an agreement remains distant.
He would like to seal a deal as soon as possible as former residents are ageing and dwindling in number.
Putin, who is making his first visit to Japan in more than a decade, said he wanted to end the "anachronism" of the two countries not having a World War II peace treaty.
"But how to do this is a difficult question," he told Japanese media.
Al Jazeera's Natasha Ghoneim, reporting from Sakhalin, said: "The islands are very remote, not well developed, and most Russian have never been there. There are around 19,000 people living there. Most of them are Russian military personnel and their families.
"But from a military standpoint they are strategic and it is believed to be oil and gas resources there as well as resources for the fishing industry."
Russia hopes to clinch deals with Japanese companies as part of an Asian pivot in response to a decision by Western governments, including Japan, to impose sanctions in 2014 over Moscow's role in the Ukraine conflict.
Putin told the Japan's Yomiuri newspaper this week that the goal of a peace treaty would be harder to achieve if Russia remained subject to Japanese sanctions.
However, Japan's trade minister, Hiroshige Seko, has ruled out any economic cooperation with Russia that would undermine G7 unity on the sanctions.
For Abe, the issue is also a "legacy" from his late father Shintaro, who took the lead in negotiations with Moscow as a foreign minister but died in 1991 after pushing for talks while suffering from cancer
The two leaders will move from Nagato to Tokyo on Friday for more talks and a joint press appearance before attending an economic forum.
Source: News agencies