Communism developed in Russia and China because of factors unique to the social and economic situations in these two countries and because of the charismatic leadership of each country's respective communist leaders, namely Vladimir Lenin and Mao Zedong. Karl Marx, who founded communism as ideology in 1848 said the necessary factors for its practical implementation were an elite class who controlled industry and large populations of workers, factors that all major European countries shared by the twentieth century, and which applied to China by the start of World War II, when Communism took hold there.
Marx and Engels
In 1848, Karl Marx and Friedrich Engels published the Communist Manifesto, which called on workers of the world, or the proletariat, to unite against the bourgeoisie or the class of factory owners and investors who grew rich and powerful at the expense of the workers. Marx and Engels predicted that communism would arise in countries with these two classes present. Marx expressed the belief that working class members of society should actively revolt against the bourgeoisie to overthrow capitalism and change the social order. The writing of Friedrich Engels have a uniquely feminist bent and called out the oppression of patriarchal societies as a key to maintaining capitalist order.
Russia's successful communist revolution was not the result of Vladimir Lenin's charismatic leadership. Though born into a wealthy middle class in 1870, Lenin became involved in worker and revolutionary politics while at university, and eventually became a prominent Marxist intellectual who wrote books and pamphlets criticized the capitalist order. Lenin's charisma would in 1903 help him become leader of the Bolsheviks, the radical faction in Russia's communist party that would ultimately establish communism in Russia in 1917.
The October Revolution
In February of 1917, a revolution in Russia overthrew the czar and installed a provisional democratic government where power was shared between a variety of factions, including communists. Lenin, in exile in Switzerland at the time, returned to Russia and with his status and charisma helped start a second revolution, known as the October Revolution, which overthrew the moderate democratic government and put the Bolsheviks in power. Without Lenin's charismatic leadership, the Russian Communist party would have been content with the democratic revolution, a type of revolution that many European countries had seen. Lenin, however, used his influence put his faction in power, and make Russia into a communist country.
Communism in China followed a similar trajectory, relying on a particularly charismatic individual, in this case Mao Zedong. Like Lenin, Mao was born to a wealthy family in 1893, but became involved in revolutionary politics while at university in the 1910s. He rose quickly in the Communist Party of China, and became a prominent military leader by the 1940s and helped fight the Japanese during World War II, as well as the non-communist Chinese Nationalists led by Chiang Kai-shek. In 1949, Mao was able to defeat the nationalists and establish the communist People's Republic of China, with himself as its leader.