The Sega Mark III is a video game console that was released by Sega in Japan in 1985. It is the successor to the Sega SG-1000 and SG-1000 II consoles. The Mark III was later rebranded and released internationally as the Sega Master System. The Sega Master System was Sega's first internationally successful console, although it faced strong competition from Nintendo's Nintendo Entertainment System (NES). The Master System had a library of games, including popular titles like "Alex Kidd in Miracle World" and "Phantasy Star." The Sega Master System had some technical advantages over the NES, such as better graphics and sound capabilities, but it ultimately did not achieve the same level of success in terms of sales.