Useful Notes: Sega Master System

"Now, There Are No Limits."

The Master System, while far from being Sega's first 8-bit game console, was notably their first foray into the international gaming market, released in 1986 in response to the launch of the Nintendo Entertainment System in North America.

Realizing that the SG-1000 was too antiquated to compete with Nintendo's Family Computer on a global scale (the SG-1000 was essentially identical to the ColecoVision and the original MSX, as they were all built from common shelf parts), Sega significantly upgraded the console's technical capabilities for its third iteration. Released on October 1985, this new version of the console was dubbed the Sega Mark III and featured a slightly faster CPU and an upgraded video display processor over previous models (bringing it on par with both the Famicom and the MSX2), while having backwards compatibility with all legacy SG/SC series software and peripherals. Cosmetically the Sega Mark III hardware was very similar to the SG-1000 II, aside from the addition of a built-in card slot, meaning that it could play games in so-called MyCard format in addition to traditional cartridges, as well as different placement for the controller ports (which were moved from the rear to the front) and the power switch (which was placed from the front to the back).

In the same way the Famicom became the NES outside Japan, the Sega Mark III was heavily redesigned for its export version (codenamed the "Mark IV"), receiving a black casing that would become a trademark for all subsequent Sega platforms (at least in the west) up until the Dreamcast. The console was originally marketed as the Sega Video Game System in North America (and simply referred as the Sega System in technical documentations) and was initially sold in two bundles: the "Sega Base System" and the "Sega Master System". Despite this, all the consoles produced had "Master System/Power Base" printed on them, regardless of the bundle purchased, and even the system's BIOS referred to the platform as the Master System, which is how it became the standardized name. The Mark III would be relaunched in Japan in 1987 with the Master System name and styling, and also with a built-in FM sound chip (never included in the export versions and sold separately as an add-on for the Mark III) to enhance the quality of chiptunes, along with a rapid fire switch instead of a reset button.

All things considered, the Master System was more advanced than the NES on a surface level, although the NES was able to keep up thanks to the inclusion of memory mappers in later game cartridges that expanded the hardware's capabilities. Ultimately, Sega failed to wrestle away the majority of the market share away from Nintendo due to their stranglehold on third party developers with their strict exclusivity policy. The unfortunate timing of the PC Engine's launch in Japan, with its graphical capabilities that blew away both the Famicom and the Mark III, didn't help matters, which forced Sega to come up with a new system that could succeed the Master System and compete adequately with the emerging 16-bit generation: the Mega Drive, otherwise known as the Genesis in North America.

The Mark III/Master System was discontinued in early 1989 in Japan, a few months after the launch of its successor in the end of 1988. It lasted only a few more years in the United States as a budget-priced alternative to the Genesis in the form of the redesigned Master System II (aka "Mark IV Jr."), before being discontinued in 1991. However, it did gain a lot of ground in Europe and South America, especially in Brazil, where it was still receiving new titles by the mid-to-late '90s (including a version of Street Fighter II). The Master System's popularity in the UK in particular was helped by a bungled distribution campaign from Nintendo which meant that the NES was so rare in Britain as to be practically mythical.

Although Sega's own series didn't really gain ground until the Mega Drive, their popular Phantasy Star series got its start here. Their handheld, the Game Gear, uses hardware quite comparable with the Master System, which facilitated the development of ports and multiplatform releases on both platforms. In fact, converters exist that allow Master System games to be played on the Game Gear and vice-versa.

The Sega MyCard format (called "Sega Cards" outside Japan) was very similar to the HuCard format later employed by NEC and Hudson Soft for the PC Engine, in which games were sold in small credit card sized IC chips that were smaller and easier to produce than cartridges. In fact, the first year of Mark III software in Japan consisted almost entirely of MyCard releases, as its first "Gold Cartridge" game (Fantasy Zone) came out almost a year after the console was launched. However, the vast majority of the MyCard games in Japan were actually developed to be compatible with SG-1000 hardware through the Card Catcher cartridge add-on, and only a handful of MyCards (15 to be exact) were designed to run exclusively on the Mark III. By the time the Master System was launched in North America, Sega was already phasing out MyCards and going back to traditional cartridges that could hold more ROM space. The card slot was ultimately removed from the Master System II redesign of the console (consequently rendering the SegaScope 3D glasses incompatible as well) and many Sega Card games ended up being reissued in cartridge format in Europe.


  • The CPU, a Zilog Z80, runs at 3.55 or 3.58 MHz, depending on the region.
  • The graphics are handled by the Video Display Processor, a modified version of the TI 9918/9928 GPU MSX and Coleco also used.


  • Like the NES, SMS sprites are 8x8 or 8x16 pixels, with up to 64 on screen.

  • Resolution was 256x224 pixels.
  • 32 colors were allowed on screen, out of 64 total.

  • The system's basic sound functionality included three square wave channels, a noise generator and a DPCM channel. This was the only area in which the Master System's hardware was noticeably inferior to that of the NES, lacking a triangle channel and any of the nifty hardware effects that the NES could apply to music and sound effects, although it was still way ahead of what the Atari 7800 had to offer.
  • That is unless you lived in Japan, where an FM Sound Unit could be purchased separately as an add-on for the Mark III, which connected into the console's expansion port, enhancing the sound quality of all compatible titles (over 40 released in Japan). The add-on employs a Yamaha YM2413 sound chip, which is very similar to the YM2612 later used by the Genesis/Mega Drive, adding nine extra sound channels that provided a superior sound quality over most Famicom/NES games (in turn, the only Famicom cartridge to output FM audio was Konami's Lagrange Point, which utilized a customized mapper). Unfortunately the add-on was never released in the west due to the omission of the expansion port from the Master System redesign of the console, although the Japanese MK-2000 model has the Yamaha chip built into the hardware to compensate for this. An FM Sound Unit can still be installed into a western console through modding.
    • Due to the abrupt discontinuation of the Mark III/Master System in Japan, certain games that were programmed to be compatible with the FM Sound Unit ultimately ended up having overseas releases only, such as Ultima IV and OutRun 3D, thus the only way to enable FM sounds in these games (besides emulation) is through console modding or by playing them on a Japanese console with a converter. With Wonder Boy III: The Dragon's Trap in particular, the game will only enable FM sounds when played on a Japanese console.


Original Titles

Ported, Reformulated, or Concurrently Developed

Alternative Title(s):

Master System, Sega Mark III