(i) The system in which only one party is allowed to control and run the government is called one-party system. For example, China. (ii) In some countries, power usually changes between two main parties. Several other parties may exist, contest elections and win a few seats in the national legislatures. But only two main parties have a serious chance of winning majority of seats to form government. Such a party system is called bi-party or two party system. For example, the United States of America, The United Kingdom. (iii) A multi-party system is wheremany parties compete for power and government will often pass between coalitions formed by different combinations of parties (e.g. Italy, Israel). This is distinct from other party systems, particularly the two party system, where power and government passes between only two parties.