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 that was signed on 20 January 1925.
[2] Following the defeat of the Russian Empire in the Russo-Japanese War of 1904–1905, co-operative relations between Russia and Japan were gradually restored by four sets of treaties signed between 1907 and 1916.
However, the collapse of the Romanov dynasty, followed by the Bolshevik Revolution and 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 and 1925, Japan agreed to extend diplomatic recognition to the Soviet Union and to withdraw its troops from the northern half of Sakhalin island.
Coal and oil companies, and the Imperial Japanese Navy, invested in northern Sakhalin, creating the grounds for concessions.