real-time strategy

   Real-time strategy (RTS) is a subgenre of strategy video games that doesn't progress incrementally in turns, but allow all players to play simultaneously, in "real time". In a real-time strategy game, each participant positions structures and maneuvers multiple units under their indirect control to secure areas of the map and/or destroy their opponents' assets. In a typical RTS game, it is possible to create additional units and structures, generally limited by a requirement to expend accumulated resources. These resources are in turn garnered by controlling special points on the map and/or possessing certain types of units and structures devoted to this purpose. More specifically, the typical game in the RTS genre features resource-gathering, base-building, in-game technological development, and indirect control of units.

   The genre recognized today as "real-time strategy" emerged from an extended period of evolution and refinement. Games sometimes perceived as ancestors of the real-time strategy genre were never marketed or designed as such. As a result, designating "early real-time strategy" titles is problematic because such games are being held up to modern standards. The genre initially evolved separately in the United Kingdom, Japan, and North America, afterward gradually merging into a unified worldwide tradition.

     Ars Technica traces the genre's roots back to Utopia (1981), citing it as the "birth of a genre", with a "real-time element" that was "virtually unheard of", thus making it "arguably the earliest ancestor of the real-time strategy genre".

    According to Ars Technica, Utopia was a turn-based strategy game with hybrid elements that ran "in real-time but events happened on a regular turn-based cycle." According to Brett Weiss, Utopia is often cited as "the first real-time strategy game." According to Matt Barton and Bill Loguidice, Utopia "helped set the template" for the genre, but has "more in common with SimCity than it does with Dune II and later RTS games."

      Allgame listed War of Nerves as the oldest "2D Real-Time Strategy". Barton also cites Cytron Masters (1982), saying it was "one of the first (if not the first) real-time strategy games [sic]." On the other hand, Scott Sharkey of 1UP argues that, while Cytron Masters "attempted real time strategy", it was "much more tactical than strategic" due to "the inability to construct units or manage resources". BYTE in December 1982 published as an Apple II type-in program Cosmic Conquest. The winner of the magazine's annual Game Contest, the author described it as a "single-player game of real-time action and strategic decision making". The magazine described it as "a real-time space strategy game". The game has elements of resource management and wargaming.

    In the United Kingdom, the earliest real-time strategy games are Stonkers by John Gibson, published in 1983 by Imagine Software for the ZX Spectrum, and Nether Earth for ZX Spectrum in 1987. In North America, the oldest game retrospectively classified as real-time strategy by several sources is The Ancient Art of War (1984), designed by Dave and Barry Murry of Evryware, followed by The Ancient Art of War at Sea in 1987.

      In Japan, the earliest is Bokosuka Wars (1983), an early strategy RPG (or "simulation RPG"); the game revolves around the player leading an army across a battlefield against enemy forces in real-time while recruiting/spawning soldiers along the way, for which it is considered by Ray Barnholt of 1UP.com to be an early prototype real-time strategy game. Another early title with real-time strategy elements is Sega's Gain Ground (1988), a strategy-action game that involved directing a set of troops across various enemy-filled levels. TechnoSoft's Herzog (1988) is regarded as a precursor to the real-time strategy genre, being the predecessor to Herzog Zwei and somewhat similar in nature, though primitive in comparison.

IGN cites Herzog Zwei, released for the Sega Mega Drive/Genesis home console in 1989 as "arguably the first RTS game ever", and it is often cited as "the first real-time strategy game" according to Ars Technica. It combines traditional strategy gameplay with fully real-time, fast-paced, arcade-style action gameplay, featuring a split-screen two-player mode where both players are in action simultaneously and there are no pauses while decisions are taken, forcing players to think quickly while on the move. In Herzog Zwei, though the player only controls one unit, the manner of control foreshadowed the point-and-click mechanic of later games. Scott Sharkey of 1UP argues that it introduced much of the genre conventions, including unit construction and resource management, with the control and destruction of bases being an important aspect of the game, as were the economic/production aspects of those bases. Herzog Zwei is credited by 1UP as a landmark that defined the genre and as "the progenitor of all modern real-time strategy games." Chuck Sperry cited Herzog Zwei as an influence on Dune II.

      Notable as well are early games like Mega-Lo-Mania by Sensible Software (1991) and Supremacy (also called Overlord – 1990). Although these two lacked direct control of military units, they both offered considerable control of resource management and economic systems. In addition, Mega Lo Mania has advanced technology trees that determine offensive and defensive prowess. Another early (1988) game, Carrier Command by Realtime Games, involved real-time responses to events in the game, requiring management of resources and control of vehicles. The early game SimAnt by Maxis (1991) had resource gathering, and controlling an attacking army by having them follow a lead unit. However, it was with the release of Dune II from Westwood Studios (1992) that real-time strategy became recognized as a distinct genre of video games.f video games.