The Soviet–Japanese Basic Convention (日ソ基本条約? Nisso Kihon Jōyaku) was a treaty normalizing relations between the Empire of Japan and the Soviet Union, signed on 20 January 1925. Ratifications were exchanged in Beijing on February 26, 1925. The agreement was registered in League of Nations Treaty Series on May 20, 1925.
Following the defeat of the Russian Empire in the Russo-Japanese War of 1904–1905, cooperative relations between Russia and Japan were gradually restored via four sets of treaties signed between 1907 and 1916. However, the collapse of the Romanov dynasty, followed by the Bolshevik Revolution, followed by the Japanese Siberian Intervention created a strong distrust between Japan and the newly founded Soviet Union.
Following a series of negotiations held in Beijing in 1924–1925, Japan agreed to extend diplomatic recognition to the Soviet Union, and to withdraw its troops from the northern half of Sakhalin island. In return, the Soviet Union agreed to honor the provisions of the Treaty of Portsmouth and to re-examine all other treaties between the former Russian Empire and Japan, including the Fishery Convention of 1907.
The treaty was signed by Lev Mikhailovich Karakhan of the Soviet Union and Kenkichi Yoshizawa of Japan on 20 January 1925.