Sega Mark III video game system review! Classic Game Room reviews the SEGA MARK III game console from Sega released in 1985. The Sega Mark III is basically the Japanese Sega Master System and plays both Sega SG-1000 video games and Mark III & Japanese Sega Master System games. The Mark III has many improvements over the Sega SG-1000 Mark II including front controller ports, a built-in Sega card reader and compatibility with Sega Genesis Model 1 power supplies and AV cables!!