The Russo-Japanese War was a war between the Empire of Japan and the Russian Empire between 1904 and 1905. The Japanese won the war, and the Russians lost.

The war happened because the Russian Empire and the Empire of Japan disagreed over who should get parts of Manchuria and Korea. The war was fought mostly on the Liaodong Peninsula and Mukden, the seas around Korea, Japan, and the Yellow Sea. The politics of both countries in the war were very complicated, but both wanted to gain land and economic benefits.

The Chinese Empire of the Qing Dynasty was large but weak, and it was Qing land and possessions that were fought over. For example, Korea had been under Qing rule but was seized by Japan. Russia wanted a warm-water port on the Pacific Ocean for its navy and trade. The harbour at Vladivostok freezes over in the winter, but Port Arthur (now called the Liaodong Peninsula in China) can be used all year round. Russia had already rented the port from the Qing and had got permission to build a Trans-Siberian railway from St Petersburg to Port Arthur.

Causes 
Russia wanted a warm-water Pacific Ocean port for trade and its navy. Japan wanted to expand her empire into Korea and China. Japan thought that when Russia completed its railway in 1906, it would be able to beat Japan in a war by being able to supply large numbers of troops there.  

To avoid war, Japan wanted to compromise with Russia even if it got the better deal. Japan wanted a more of Korea and China than it thought Russia would offer. Japan decided to attack before the railway was complete so that it could do well in a war against Russia.

The war started with a Japanese surprise attack on Port Arthur and continued with Japanese victories in Manchuria and elsewhere. The last major battle was at Tsushima Strait and destroyed the Russian Navy.

Peace treaty and aftermath 
US President Theodore Roosevelt helped Russia and Japan make peace after the war. That made him win a Nobel Prize. Russia had to give up all influence in the Far East. The Russian people were very angry at the government and at Tsar Nicholas II for not continuing the war because everyone was sure that Russia could have won. That is true because Japan was bankrupt and would have suffered an economic crisis after just a few more months of fighting. Russia's army was also much stronger than Japan's and had very large reserves to replace the soldiers she lost. However, Japan had no men with military training to replace its losses and no money to give new men training.

The Japanese got Port Arthur and the Russian railway in Manchuria. Five years later, in 1910, Japan took over Korea. Japan would continue to grow its empire in Asia until World War II. The Russian defeat was one of the reasons for the Russian Army's great improvement after 1904, which helped start the European arms race that was a cause of World War I. The war also contributed to the Russian Revolution and to the Russian Civil War in 1917. Vladimir Lenin, who helped start the revolution, wanted Russia to lose the war since that showed that the tsar was losing power.

References

Further reading
 Asakawa, Kanichi. (1905). The Russo-Japanese Conflict: Its Causes and Issues. Boston: Houghton-Mifflin. OCLC 2418247; reprinted by Kennikat Press, Port Washington, New York, 1970.
 Koda, Yoji.  "The Russo-Japanese War: Primary Causes of Japanese Success,"  Naval War College Review (Spring 2005)
 Mutsu, Munemitsu. (1982). Kenkenroku (trans. Gordon Mark Berger). Tokyo: University of Toyko Press. ;  OCLC 252084846
 Nish, Ian, ed. The Russo-Japanese War, 1904-5 Folkestone, Kent : Global Oriental.  ;  OCLC 56955351

Wars involving Russia
Wars involving Japan