Some experts say an agreement between the Japanese and Russian leaders to speed up peace treaty negotiations could mark an important moment in history.
It comes after Shinzo Abe said he and Vladimir Putin agreed to forge ahead with talks based on a decades-old declaration.
Kyoto Sangyo University professor Kazuhiko Togo said, "I think this is the historical turning point of the negotiation. For the first time two governments have agreed on the fundamental structure of possible agreement. If we do not start now, we will run the risk of being overtaken by the time and no conclusion will be reached of any kind. And that would be detrimental."
After meeting with Putin in Singapore on Wednesday, Abe said the 2 leaders agreed to use a 1956 joint declaration as the basis for talks.
That's where the two islands' return is spelled out. A former Russian diplomat says his country is also keen to put an end to the dispute.
Former Russian Ambassador to Japan Alexander Panov said, "Russia solved many territorial problems. The last one is with Japan. Only Putin recognizes this declaration is a treaty because this declaration was ratified by the parliaments of both countries so this is absolutely legal document which no one can ignore."
The two countries never signed a peace treaty at the end of World War Two.
The stumbling block has been a territorial issue over 4 Russian-controlled islands. Japan claims them. The government maintains they are an inherent part of Japan's territory. It says they were illegally occupied after the war.
Putin had previously floated the idea of signing a peace treaty without any preconditions by the end of the year.
Abe later said Japan couldn't do that until the territorial dispute is resolved.