
Many 4X computer games were published in the mid-1990s, but were later outsold by other types of strategy games. The first 4X computer games were turn-based, but real-time 4X games are common. The earliest 4X games borrowed ideas from board games and 1970s text-based computer games. Emphasis is placed upon economic and technological development, as well as a range of military and non-military routes to supremacy. The gameplay involves building an empire.

4X (abbreviation of Explore, Expand, Exploit, Exterminate) is a subgenre of strategy-based computer and board games, and includes both turn-based and real-time strategy titles.
