The Russian Civil War was a multi-party war that broke out after the Bolsheviks seized power in the October Revolution.

The two main sides were the Bolsheviks, known as the 'Reds,' and a loose coalition of their opponents, known as the 'Whites.'

The White movement was ideologically diverse, including monarchists, liberals, and non-Bolshevik socialists, and lacked a unified leadership.

The war was also complicated by the intervention of several foreign powers, including Britain, France, Japan, and the United States, who supported the Whites.

The Bolsheviks held the advantage of controlling the industrial heartland of Russia and its railway network.

The Red Army was organized into a formidable fighting force under the command of Leon Trotsky.

The Bolsheviks implemented a ruthless policy of 'War Communism' to supply their army and control the economy.

The 'Red Terror,' a campaign of political repression by the secret police (the Cheka), was used to eliminate internal opposition.

The Whites were ultimately defeated due to their internal divisions, lack of popular support, and the Bolsheviks' superior organization and control of key territory.

The civil war was incredibly brutal, resulting in millions of deaths from fighting, famine, and disease, and it cemented Bolshevik control over Russia.