The Russo-Japanese War (8 February 1904 – 5 September 1905) was fought between the Russian Empire and the Empire of Japan over rival imperial ambitions in Manchuria and the Korean Empire. The major land battles of the war were fought on the Liaodong Peninsula and near Mukden in Southern Manchuria, with naval battles taking place in the Yellow Sea and the Sea of Japan.
Russia had pursued an expansionist policy in Siberia and the Far East since the reign of Ivan the Terrible in the 16th century. At the end of the First Sino-Japanese War, the Treaty of Shimonoseki of 1895 had ceded the Liaodong Peninsula and Port Arthur to Japan before the Triple Intervention, in which Russia, Germany, and France forced Japan to relinquish its claim. Japan feared that Russia would impede its plans to establish a sphere of influence in mainland Asia, especially as Russia built the Trans-Siberian Railroad, began making inroads in Korea, and acquired a lease of the Liaodong Peninsula and Port Arthur from China in 1898. Japan signed the Anglo-Japanese Alliance in 1902, and began offering to recognize Russia's dominance in Manchuria in exchange for recognition of Korea as part of Japan's sphere of influence. However, this was rejected by Russia.