It is a redesign of the Sega Mark III released in 1985 in Japan, 1986 in North America, 1987 in Europe (and later in Japan with an FM synthesizer) and 1989 in Brazil.
It is a redesign of the Sega Mark III that released 1985 in Japan. The Master System released on 1986 in North America, 1987 in Europe and 1989 in Brazil.