The Treaty of Saint Petersburg between Japan and Russia is ratified, providing for the exchange of Sakhalin for the Kuril Islands.

The Treaty of Saint Petersburg (Japanese: 樺太・千島交換条約, romanized: Karafuto-Chishima Kōkan Jōyaku; Russian: Петербургский договор) between the Empire of Japan and Empire of Russia was signed on 7 May 1875, and its ratifications exchanged at Tokyo on 22 August 1875. The treaty itself went into effect in 1877.Its terms stipulated that Japan cedes to Russia the part of Sakhalin island it then owned in exchange for the group of the Kuril Islands owned by Russia (between Iturup island and the Kamchatka Peninsula). Consequently, Sakhalin island as a whole became Russian territory, and the entire Kuril archipelago Japanese territory.The authentic text of the treaty is written in French. Differences with its Japanese translation contributed to the controversy on what constitutes the Kuril islands, claims to which Japan renounced in 1951 by the Treaty of San Francisco. The Treaty of Saint Petersburg (1875) is part of an ongoing, and long-standing, territorial dispute between Russia and Japan over the jurisdiction of the Kuril Islands.