The New Economic Policy was introduced in the Soviet Union in 1921 when the country began to engage in peaceful economic development after the civil war. The main elements of the policy were as follows. The system of collecting surplus grain was replaced with a grain tax; peasants could sell their surplus grain freely after they had paid this tax in kind. Commerce was developed, and free trade and private businesses were allowed within certain limits. An economic accounting system was introduced in state-owned enterprises, and some of these enterprises were leased, under a form of state capitalism, to individuals or to foreign capitalists.