2. The Port KorsakovKorsakov The Russo-Japanese War was fought between the Russian Empire and the Empire of Japan over rival imperial ambitions in Manchuria and Korea. The major theatres of operations were the Liaodong Peninsula and Mukden in Southern Manchuria and the seas around Korea, Japan and the Yellow Sea. Russia sought a warm-water port on the Pacific Ocean for its navy and for maritime trade. Vladivostok was operational only during the summer, whereas Port Arthur, a naval base in Liaodong Province leased to Russia by China, was operational all year. Since the end of the First Sino–Japanese War in 1895, Japan feared Russian encroachment on its plans to create a sphere of influence in Korea and Manchuria. Russia had demonstrated an expansionist policy in the Siberian Far East from the reign of Ivan the Terrib... From Wikipedia, the free encyclopedia.