Japan and the former Soviet Union restored diplomatic relations a decade after World War II, but a dispute over a cluster of islands kept them from signing a peace treaty. Russian President Vladimir Putin is in Japan this week for talks with Japanese Prime Minister Shinzo Abe on the issue.
A timeline of the rocky relations between Japan and Russia, dating to the 19th century:
— 1855: Japan and Russia sign the Treaty of Shimoda, starting diplomatic relations.
— 1905: Japan defeats Russia in the Russo-Japanese War. U.S. President Theodore Roosevelt mediates a negotiated end to the fighting.
— 1941: Japan and the Soviet Union sign a neutrality pact pledging to respect the sovereignty of Japan's puppet state in Manchuria.
— 1945: The Soviet Union declares war on Japan a week before Tokyo's Aug. 15 surrender, scrapping the neutrality pact and seizing the southern Kuril islands.
— 1956: The two countries sign the Japan-Soviet Joint Declaration, ending the state of war and restoring diplomatic ties. The Soviet Union agrees to return two of the four islands after a peace treaty is signed.
— 1960s-1970s: No progress on the territorial dispute during the Cold War.
— 1991: Russian leader Mikhail Gorbachev visits Japan after the fall of the Berlin Wall in 1989. He signs a communique recognizing the territorial dispute.
— 1993: Russian President Boris Yeltsin and Japanese Prime Minister Morihiro Hosokawa sign a "Tokyo Declaration" in which they agree to continue negotiations toward a peace treaty.
— 2001: Putin becomes president. Japan and Russia agree to recognize the 1956 joint declaration as the starting point of negotiations to resolve the island issue.
— 2010: Relations cool after Russian President Dmitry Medvedev visits one of the four disputed islands.
— 2012: Putin and Abe return to leadership of their respective countries and foster closer ties.
— 2014: Russia annexes Crimea, putting ice on efforts to improve bilateral relations.
— 2016: Putin meets Abe in Japan for talks on the territorial issue.