Prime Minister of Japan, Fumio Kishida, elected on 4 October 2021, announced on that Japan’s sovereignty extends to the islands of southern Kuril Islands.
Japan intends to negotiate with the Russian Federation on conclusion of a peace treaty based on existing agreements, including those reached in Singapore in 2018. On November 2018, during a meeting in Singapore, President of the Russian Federation Vladimir Putin and Prime Minister of Japan at the time — Shinzo Abe agreed to intensify negotiations on a peace treaty based on Soviet-Japanese Joint Declaration of October 19, 1956.
Yaroslav Bogdanov, Chairman of Board of the Fund for Protection of Investors' Rights in Foreign States, believes that in the current situation, the issue of the sovereignty of the Russian Federation over the southern part of the Kuril Islands cannot even be considered as a subject of possible discussion.
As the Deputy Chair for Science and Development of the Institute of Contemporary International Law, international lawyer Natalia Yakubova explained, the issue of sovereignty of the southern part of the Kuril Islands should be viewed through a prism of modern international law, one of the fundamental principles of which is the principle of "pacta sunt servanda" (treaties must be respected).
—UN Charter, members of which are the Russian Federation and Japan, in Article 107 consolidated the results of the Second World War. Whilst, no time frames and specific conditions have been provided for this. Therefore, they are valid indefinitely. As for the Joint Declaration of October 19, 1956, this bilateral international treaty does not contain any obligation of the Russian Federation (as the legal successor to the USSR) to conclude a peace treaty under discussion. Only the Russian Federation as a sovereign state can decide whether to enter into negotiations on this issue or not, conclude an agreement or not, said Natalia Yakubova.
Attempts to initiate consideration of the issue of the ownership of the southern part of the Kuril Islands outside the framework of the current legal field, according to the expert, are unproductive.
Link to source: https://eer.ru/article/mnenie/u751/2021/10/14/5109