4X stands for eXploration, eXpansion, eXploitation, eXtermination. As a subgenre of strategy games, it is adjacent to grand strategy genre.

4X games were among the first widely popular computer strategy games in the history. 1991 saw release of the first of edition of the widely-known franchises Civilization (over 40 million copies sold). Since then, there were five main continuations (up to Civilization VI in 2016), as well as some contenders, such as Old World (2021), Humankind (2021), and Endless series (2012, 2014, 2017).

Features of 4X games

  • focus on empire building, starting almost from zero
  • board-like map, usually using hexagons
  • discovering procedurally generated world (exploration), usually by directly moving units into unknown areas
  • taking over parts of the world (expansion), usually by establishing cities or setting up colonies
  • using existing resources (exploitation), usually by directing cities to collect nearby resources
  • competition with other empires (extermination), usually with military conflicts
  • technology trees
  • building units, improving, moving on the map
  • specified, often wide, time span of the game
  • abstract resource management
  • unlocking new tools, units, content over time
  • usually turn-based
  • tactical level, sometimes in a form of separate battle mode
  • a few to dozen symmetrical players interacting via diplomacy
  • scoring system between empires, clear path to victory

Differences between 4X and grand strategy games

Although both 4X and grand strategy have various definitions and intersecting playerbase, a few significant differences can be listed as most often mentioned:

  • preexisting asymmetrical world in grand strategies in contrast to new symmetrical world in 4Xs (in other words: being thrown into a living world vs colonizing a randomly generated world)
  • realistic sandbox/simulation feeling in grand strategies in contrast to more board-like and gameplay-focused feeling in 4Xs (in other words: military divisions vs a single unit of archers)
  • historical accuracy and flavor in grand strategies in contrast to unrealistic entertainment-focused scenarios in 4Xs (in other words: Wall Street Crash of 1929 vs Cleopatra fighting with Gandhi)
  • high economic, diplomatic, military complexity in grand strategies in contrast to reduced direct control and main influence exerted with implied actions in 4Xs (in other words: starting a war after producing casus belli vs sending military units to attack enemy city)
  • less goal-directed gameplay in grand strategies in contrast to preset victory conditions in 4Xs (in other words: roleplaying vs competition)

Both subgenres sometimes borrow features from each other (for instance, Europa Universalis implementing more board-like mechanisms and Shadow Empire incorporating realistic simulation) or even are blended into a single game. The primary example of this combination is Paradox-developed Stellaris, which has been described as both a 4X game (intense exploration, randomly generated galaxy, technology tree) and a grand strategy game (to complex inter-species interaction, real-time gameplay).

Origins of 4X games

As with most PC strategies, 4X games originated from board games. Before digital Civilization, board game with same name and many similar mechanics was published in 1980. Much earlier but also more wider inspiration can be found in classic board game Risk, first released in 1957, which also heavily influenced “map-painting” aspect of grand strategy games. Similarly to relation between Civilization board game and popular digital 4X, grand strategy games have seen direct connection between Europa Universalis board game (1993) and later computer grand strategies, with additional significant influences of board war games.