The Sega Mark III was Sega’s third video game system. It featured numerous hardware upgrades such as improved graphics and improved sound (which could be improved even further with the FM Sound Unit). It was compatible with all Sega SG-1000 games and peripherals including the SK-1100 keyboard add-on which would also allow Sega SC-3000 games to be played on the Mark III.
The Sega Mark III also included a built-in Card Catcher slot which meant that My Cards could be used in addition to cartridges.
Even with all the technological improvements, the Sega Mark III sold poorly compared to the Famicom.
The Sega Mark III would be the basis for the Sega Master System.