Russo-Japanese War

1904-02-08 - 1905-09-05

The Russo-Japanese War was fought from 8 February 1904 to 5 September 1905 between the Russian Empire and the Empire of Japan over rival ambitions in Manchuria and Korea. Japan opened the war with a surprise attack on the Russian fleet at Port Arthur, then won major land battles at Mukden and destroyed the Russian Baltic Fleet at the Battle of Tsushima. The Treaty of Portsmouth, mediated by U.S. president Theodore Roosevelt, recognized Japanese interests in Korea and awarded Japan Russia's lease on the Liaodong Peninsula, the South Manchuria Railway, and the southern half of Sakhalin. Japan's victory over a European power made it a great power and damaged Russia's prestige.