The Russo-Japanese War (; ) was fought between the Empire of Japan and the Russian Empire during 1904 and 1905 over rival imperial ambitions in Manchuria and the Korean Empire. The major theatres of military operations were in Liaodong Peninsula and Mukden in Southern Manchuria, and the Yellow Sea and the Sea of Japan.
Russia sought a warm-water port on the Pacific Ocean both for its navy and for maritime trade. Vladivostok remained ice-free and operational only during the summer; Port Arthur, a naval base in Liaodong Province leased to Russia by the Qing dynasty of China from 1897, was operational year round.
Russia had pursued an expansionist policy east of the Urals, in Siberia and the Far East, since the reign of Ivan the Terrible in the 16th century. Since the end of the First Sino-Japanese War in 1895, Japan had feared Russian encroachment would interfere with its plans to establish a sphere of influence in Korea and Manchuria.
Seeing Russia as a rival, Japan offered to recognize Russian dominance in Manchuria in exchange for recognition of the Korean Empire as being within the Japanese sphere of influence. Russia refused and demanded the establishment of a neutral buffer zone between Russia and Japan in Korea, north of the 39th parallel. The Imperial Japanese Government perceived this as obstructing their plans for expansion into mainland Asia and chose to go to war. After negotiations broke down in 1904, the Imperial Japanese Navy opened hostilities in a surprise attack on the Russian Eastern Fleet at Port Arthur, China on .
Although Russia suffered a number of defeats, Emperor Nicholas II remained convinced that Russia could still win if it fought on; he chose to remain engaged in the war and await the outcomes of key naval battles. As hope of victory dissipated, he continued the war to preserve the dignity of Russia by averting a "humiliating peace". Russia ignored Japan's willingness early on to agree to an armistice and rejected the idea of bringing the dispute to the Permanent Court of Arbitration at the Hague. After the decisive naval battle of Tsushima, the war was concluded with the Treaty of Portsmouth (), mediated by US President Theodore Roosevelt. The complete victory of the Japanese military surprised international observers and transformed the balance of power in both East Asia and Europe, resulting in Japan's emergence as a great power and a decline in the Russian Empire's prestige and influence in Europe. Russia's incurrence of substantial casualties and losses for a cause that resulted in humiliating defeat contributed to a growing domestic unrest which culminated in the 1905 Russian Revolution, and severely damaged the prestige of the Russian autocracy.
Historical background
Modernization of Japan
After the Meiji Restoration in 1868, the Meiji government endeavoured to assimilate Western ideas, technological advances and ways of warfare. By the late 19th century, Japan had transformed itself into a modernized industrial state. The Japanese wanted to be recognized as equal with the Western powers. The Meiji Restoration had been intended to make Japan a modernized state, not a Westernized one, and Japan was an imperialist power, looking towards overseas expansionism.
In the years 1869–73, the Seikanron ("Conquer Korea Argument") had bitterly divided the Japanese elite: one faction wanted to conquer Korea immediately, another wanted to wait until Japan was further modernized before embarking on a war to conquer Korea; significantly, no one in the Japanese elite ever accepted the idea that the Koreans had the right to be independent, with only the question of timing dividing the two factions. In much the same way that Europeans used the "backwardness" of African and Asian nations as a reason for why they had to conquer them, for the Japanese elite the "backwardness" of China and Korea was proof of the inferiority of those nations, thus giving the Japanese the "right" to conquer them.
Count Inoue Kaoru, the Foreign Minister, gave a speech in 1887 saying "What we must do is to transform our empire and our people, make the empire like the countries of Europe and our people like the peoples of Europe," going on to say that the Chinese and Koreans had essentially forfeited their right to be independent by not modernizing. Much of the pressure for an aggressive foreign policy in Japan came from below, with the advocates of "people's rights" movement calling for an elected parliament also favouring an ultra-nationalist line that took it for granted the Japanese had the "right" to annex Korea, as the "people's rights" movement was led by those who favoured invading Korea in the years 1869–73.