Artillery games are early two or three-player (usually turn-based) video games involving tanks fighting each other in combat or similar. Artillery games are among the earliest computer games developed; the theme of such games is an extension of the original uses of computer themselves, which were once used to calculate the trajectories of rockets and other related military-based calculations. Artillery games have been described as a type of "shooting game", though they are more often classified as a type of strategy video game.