Origins of the Civil War
For the Bolsheviks the civil war was a necessary phase in the revolution, a violent intensification of the class struggle. Lenin was prepared for a civil war and perhaps even welcomed it as a chance to build his party's tiny power base.
The effects of such a conflict were predictable: the polarization of the country into 'revolutionary' and 'counter-revolutionary' sides; the extension of the state's military and political power; and the use of terror to suppress dissent. In Lenin's view all these things were necessary for the victory of the Dictatorship of the Proletariat.
In military terms the civil war began on the Don River. Having fled the Bykhov Monastery, Kornilov and his 'White Guard' followers moved south to the Don to form a Volunteer Army to fight the Bolsheviks. On 9 December, the Whites took Rostov from the Reds, but two weeks later they lost it. Forced to retreat across the ice-bound Kuban steppe, they attacked Ekaterinodar, where Kornilov was killed, on 12 April.
Taking over the command, General Denikin led the Whites back to the Don. There they found the Cossack farmers in revolt against the Bolsheviks, who had seized their stocks of grain by force. By mid-June 40,000 Cossacks had joined General Krasnov's Don Army. Recapturing Rostov, the Cossacks and the Whites were in a strong position to strike north towards the Volga and link up with the Czechs and the Komuch army against the Bolsheviks.
The Czech Legion was a force of 35,000 Czech and Slovak prisoners of war on Soviet soil. Determined to fight for their country's independence from the Austro-Hungarian Empire but caught behind the German lines, they took the Volga town of Samara and installed the SR-dominated government called the Komuch (Committee of Members of the Constituent Assembly) which mobilized a fragile conscript army from the peasantry to overthrow the Bolsheviks and Brest-Litovsk.