The SG-1000, also known as the Sega Game 1000 or Sega Mark I, is a home video game console manufactured by Sega and released in Japan, Australia, New Zealand, and other regions. It was Sega's first entry into the home video game hardware business. Introduced in 1983, the SG-1000 was released on the same day that Nintendo released the Family Computer in Japan. The SG-1000 was released in several forms, including the SC-3000 computer and the redesigned SG-1000 II released in 1984. A third iteration of the console, the Sega Mark III, was released in 1985. It provided a custom video display processor over previous iterations and served as the basis for the Master System in 1986, Sega's first internationally released console.
Developed in response to a downturn in arcades in 1982, the SG-1000 was created on the advice of Hayao Nakayama, president of Sega Enterprises, Ltd. Shortly after the release, Sega Enterprises was sold to CSK Corporation, which was followed by the release of the SG-1000 II. The SC-3000 and the SG-1000 line both support a library of 76 ROM cartridge games and 29 Sega My Card games, all of which are fully compatible with the Mark III and the Japanese version of the Master System.