Russia has suspended talks with Japan over the Kuril Islands, which have been ongoing since WWII. Russia says the move was a response to Japanese sanctions over the invasion of Ukraine.
Recently, Japan described four islands whose ownership it disputes with Russia as illegally occupied in the latest version of a diplomatic Bluebook.
About Kuril Island:
The island chain known as the Kurils stretches north across the Pacific Ocean from the Japanese island of Hokkaido to the southern tip of Russia's Kamchatka Peninsula.
The Kuril Islands are a group of 56 volcanic islands in East Asia, located between the Russian Kamchatka Peninsula and Hokkaido.
They range from northeast to southwest about a mile away. 1,200 km, this separates the Okhotsk Sea from the Pacific Ocean.
They are under the jurisdiction of the Russian Federation and are part of the Sakhalin Territory, but Japan claims two large southern islands and the islands of Shikotan and Habomai, also known as the “Kuril Islands”.
Japanese people migrated north to the islands in the 18th and 19th century, including members of Hokkaido's minority Ainu community.
Treaty of Shimoda: In 1855, Russia and Japan signed the Treaty of Shimoda, which gave Japan ownership of the four southern islands and Russia ownership of everything to the north.
Communities developed on three of the islands and by the time World War II began, there were 17,000 Japanese residents.
Russia took control of the islands at the end of the war, and by 1949 it had deported all residents to Japan.
San Francisco Peace Treaty: Under the 1951 San Francisco Peace Treaty, signed between the Allies and Japan, Japan renounced "all right, title and claim to the Kuril Islands", as well as over other possessions.
But this resolved nothing, because Russia did not sign the treaty and the Japanese government has never recognised the four islands as part of the Kuril chain.
Japan-Soviet Joint Declaration: In 1956, the Japan-Soviet Joint Declaration restored diplomatic ties between the two nations, but a formal peace deal remained out of reach because of the territorial dispute.
At the time, Russia proposed returning the two islands closest to Japan, a deal Japan rejected, in part because the two islands represent only 7% of the land in question.
Since then, the dispute has remained unresolved.
The islands are surrounded by rich fishing grounds and are thought to have offshore reserves of oil and gas.
Rare rhenium deposits have been found on the Kudriavy volcano on Iturup.
Tourism is also a potential source of income, as the islands have several volcanoes and a variety of birdlife.
The Diplomatic Bluebook of Japan is an annual report on Japan's foreign policy and international diplomacy published by the Ministry of Foreign Affairs in Japan.
It has been published every year since its first issue in September 1957.