On July 15 1983 (coincidentally the same day that NES launched) Sega launched their very first console SG-1000 in Japan. So it's been just over 30 years since it launched. The SG-1000 was later improved upon and turned into Mark III (Japan) and Master System (Western markets). There was also a home computer version SC-3000 (also released in 1983).
To commemorate the 30 years that have passed since the launch of SG-1000 Sega have released a 4 disc collection of early Sega tunes in Japan.