Japan and Russia conflicting dispute about dominion of the four northern islands (Etorofu Island, Kunashir Island, Shikotan Island, Habomai archipelago). Japan collectively call them "Northern Territories", but in Russia it is called "South Kuril Islands".
The Northern Territories are the Islands of Etorofu Island, Kunashir Island, Shikotan Island and the Habomai Archipelago. Among these four islands, Etorofu Island and Kunashiri Island are located in the southern part of the Kuril Islands. The area of the Northern Territories is almost the same as Chiba Prefecture, 5036 square kilometers. In addition, Etorofu Island is located at the northernmost of the Northern Territories and is the largest island.
Japan-Soviet Joint Declaration
The official name is called "Joint Declaration between Japan and the Soviet Socialist Republic" and has restored the relationship between Japan and the Soviet Union.
Regarding the territorial dispute , it was supposed to hand over the Habomai Archipelago and Shikotan Jima to Japan after concluding a peace treaty.
(For details, it is opened on the page of the Northern Territories dispute. )
Japanese-Soviet joint statement
The Japanese-Soviet joint statement announced that it will make further efforts to improve relations between the two countries.
Yalta Conference
Yalta Conference were made by President Roosevelt of the United States, Prime Minister Churchill of England and Prime Minister of the Soviet Union about talks about the treatment plan after World War II. At this meeting, the Yalta Agreement on which the establishment of the United Nations was decided was concluded.
Japan-Soviet Neutrality Pact
It was tied between Japan and the Soviet Union to preserve peace and friendly relations.
Also, it is said that Russian President Vladimir Putin is showing a positive attitude toward solving the Northern Territories dispute, but at the Japan-Russia Summit held in Yamaguchi Prefecture in 2016 there was no major progress in the Northern Territories dispute is.
Why does Russia claim its ownership of the Northern Territories? The following are considered for the reason.
Because the Russian Navy can go out to the Pacific in winter, its military value is high. Also, in the Sea of Okhotsk, an attack type submarine equipped with nuclear weapons capable of attacking the United States and others is deployed, and the Northern Territories are "walls" which prevent America and others from invading there.