Spacewar! was the game played at the first recognized esports competition, held at Stanford University in 1972.
The event was called the Intergalactic Spacewar Olympics and took place on 19 October 1972. Stanford students competed on a PDP-10 computer running Spacewar!, a two-player space-combat simulation created in the early 1960s. The prize was a year's subscription to Rolling Stone magazine.
Spacewar! was not designed as a commercial esport. It was a research and hobbyist program, but its head-to-head format made it naturally competitive. Players controlled spacecraft, fired torpedoes and used a nearby star's gravity while trying to destroy an opponent.
The event is often described as the beginning of organized video-game competition. It predates arcade tournaments such as the 1980 Space Invaders Championship, which introduced large-scale public competition. Spacewar! is therefore associated with esports history because it supplied the game for the earliest documented tournament, not because it had a professional league or a modern prize pool.