Open world
There is no consensus on what the earliest open world game is, due to differing definitions of how large or open a world needs to be. Ars Technica traces the concept back to the free-roaming exploration of 1976 text adventure game "Colossal Cave Adventure", which inspired the free-roaming exploration of "Adventure" (1980), but notes that it wasn't until 1984 that what "we now know as open-world gaming" took on a "definite shape" with 1984 space simulator "Elite", considered a pioneer of the open world; Gamasutra argues that its open-ended sandbox style is rooted in flight simulators, such as SubLOGIC's "Flight Simulator" (1979/1980), noting most flight sims "offer a 'free flight' mode that allows players to simply pilot the aircraft and explore the virtual world". Others trace the concept back to 1981 CRPG "", which had a free-roaming overworld map inspired by tabletop RPG "Dungeons & Dragons". The overworld maps of the first five "Ultima" games, released up to 1988, lacked a single, unified scale, with towns and other places represented as icons; this style was adopted by the first three "Dragon Quest" games, released from 1986 to 1988 in Japan.
Dave Arneson
Arneson wrote up the Blackmoor setting for Judges Guild in "The First Fantasy Campaign" (1977). In 1979 Arneson and Richard L. Snider, an original "Blackmoor" player, co-authored "Adventures in Fantasy", a role-playing game that attempted to recapture the "original spirit of the Role Playing Fantasy Game" that Arneson had envisioned in the early 1970s, instead of what "D&D" had become. In the early 1980s he established his own game company, Adventure Games – staffed largely by Arneson's friends, most of whom were also members of a Civil War reenactment group – that produced the miniatures games "Harpoon" (1981) and "Johnny Reb" (1983), as well as a new edition of his own "Adventures in Fantasy" role-playing game (1981). The company also put out about a half-dozen Tékumel related books, due to Arneson's friendship with M. A. R. Barker. Adventure Games was profitable, but Arneson found the workload to be excessive and finally sold the company to Flying Buffalo. Flying Buffalo picked up the rights to Adventure Games in 1985; because Arneson owned a portion of Flying Buffalo, he let them take care of the rest of the company's stock and IP when he shut the company down.