By 1921, Harbin, northern Manchuria's largest city, had a population of 300,000, including 100,000 Russians.[77] Japan replaced Russian influence in the southern half of Inner Manchuria as a result of the Russo-Japanese War in 1904–1905. Most of the southern branch of the Chinese Eastern Railway was transferred from Russia to Japan, and became the South Manchurian Railway. Japanese influence extended into Outer Manchuria in the wake of the Russian Revolution of 1917, but Outer Manchuria had reverted to Soviet control by 1925.