MSX (Microsoft X) was a common standard for home computers proposed by Microsoft and ASCII in 1983. It came into wide use around the world as an 8-bit personal computer that could be connected to a television. As well as a BASIC interpreter (MSX-BASIC), it was equipped with a compatible DOS called MSX-DOS. Languages such as C and Pascal were also available. MSX2, an upwardly compatible standard of MSX, was announced in 1985. Game software such as "Metal Gear" and "Metal Gear 2: Solid Snake" were released for this format.

Dr. Kio Marv, kidnapped in Zanzibarland during the Zanzibarland Disturbance in 1999, was an enthusiastic gamer. He owned an MSX2 and played many games. He left a message in the ROM cartridge of MSX2.