Japan, Russia, and the Northern Territories

The Northern Territories issue is the most significant unresolved conflict between Japan and Russia. These territories were seized by the Soviet Union at the conclusion of World War II and are presently under Russian administration, but are also asserted by Japan. The 1956 joint declaration, which restored diplomatic relations between Japan and the former Soviet Union, did not reach an agreement on the return of the islands, only stating that the Habomai and Shikotan Islands would be returned to Japan following a peace treaty.

However, as of now, the two nations have not signed a treaty to formally conclude World War II hostilities.

In November 2018, Prime Minister Shinzō visited Russian President Putin in Singapore and agreed to collaborate on a peace treaty based on the Joint Declaration. Nonetheless, just a few months later, Putin expressed reservations about the potential deployment of U.S. troops in the Northern Territories should a treaty be signed. In July 2020, Russia revised its constitution to explicitly forbid the transfer of any territory, thereby impeding peace negotiations.

Following Russia's invasion of Ukraine in February 2022, Prime Minister Kishida's administration imposed economic sanctions, prompting Russia to decline participation in negotiations regarding territory or a peace treaty. Since their suspension in 2020 due to the COVID-19 pandemic, visa-free exchange programs and visits to graves by former residents of the four islands have also been halted.

In August 2026, Putin made his first visit to the Northern Territories, inspecting locations including a seafood processing facility on Etorofu Island.