The History of Video Games #22: The Sega SG-1000 Family

Updated: Jul 2

In the last article, we investigated the birth of the Sega company. Now we will look at the console they used to enter the home system market – the Sega SG-1000. Let’s dive in.

Full disclosure: This article was originally going to be about the SEGA Master System, however when researching it I realised that SEGA had made an earlier console which should be covered first. I have not seen or had any hands-on experience with any of the machines in this article so I am reliant on second-hand sources, some of which give conflicting info. Please let me know if there are any inaccuracies and I’ll amend accordingly.

I would like to thank SEGARetro, WayBackMachine, The Nostalgia Nerd and Top Hat Gaming Man as this piece would not have been possible without the info contained in their respective content.


SEGA’s first home devices were the 8-bit SG-1000 console and the SC-3000 personal computer.

SEGA SC-3000 Personal Computer
SEGA's first home system, the SC-3000 Personal Computer. Note the rubber keys.

The development of the SC-3000 was prompted by the 1982 downturn in the arcade game business. Hayao Nakayama, president of Sega Enterprises Ltd, pressed for the company to move into the home entertainment market, reasoning that SEGA’s hardware experience would enable them to succeed in the then-nascent market.

The slightly more powerful SC-3000H. Note the conventional plastic keys

Upon receiving the go-ahead, development started on the Sega Personal Computer SC-3000 – SEGA’s first and last attempt at a personal computer. During the SC-3000’s development, SEGA became aware that Nintendo was creating a games console. Not to be outdone, SEGA started work on the SG-1000 (short for Sega Computer Video Game 1000.)

SEGA's first home console, the SG-1000
SEGA's first home console, the SG-1000

Both the SC-3000 and SG-1000 were released to limited success in the Japanese, Australian, New Zealand, French, Italian and Finnish markets on the 15th of July 1983 – the same day Nintendo launched their Famicom. It was not released in America, the UK or Germany, which may account for its relative obscurity.

Strictly speaking, SEGA only released the SG-1000 in Japan, however it was rebranded for several other markets in a move similar to the one Amstrad would take with the Amstrad CPC 464 microcomputer.

In terms of graphics and sound the SG-1000 was roughly comparable to the earlier ColecoVision, with which it shares its Texas Instruments TMS9918 Video Display Controller, and much of its other internal hardware.

ColecoVision console by Coleco
The earlier ColecoVision, with which the SG-1000 shares many components

This provides the SG-1000 with a 16 colour pallet, all of which could be displayed on screen at once at a resolution of 256 x 192 pixels, with up to 32 on-screen sprites. Connection to a TV was via an RF cable. As with all RF connections, this somewhat limited the clarity of its on-screen image.

Sound was provided by the Texas Instruments SN76489A Sound chip, granting the SG-1000 four channel mono sound.

Its CPU was an 8-bit Zilog Z80 running at 3.58 MHZ, comparable to the 8-bit Zilog Z80 running at 3.5 MHz on the ZX Spectrum family of home microcomputers. The CPU of the SC-3000 ran slightly faster, at 4MHz.

The console sported 1KB of SRAM (possibly for game saves) and 16KB of VRAM. A more detailed description of its hardware specification can be found on

This resulted in a console that was underpowered compared to the Famicom. Despite this, it sold reasonably well, with 160,000 consoles sold in 1983, which far surpassed SEGA’s own estimates of circa 50,000 units. Some of this early success was likely due to the size of its game library, which was notably larger than that of the NES. For comparison, by the end of 1983, the NES had nine games, whereas the SG-1000 had 21.

Secondly, as we saw earlier, early Famicom cartridges suffered faults, which Nintendo rectified via a comprehensive product recall. This false start by Nintendo allowed SEGA to get an early foothold in the Japanese market. However, once the Famicom had overcome its teething troubles it soon took the lead, in part due to its more impressive visuals, and partly due to the popularity and fame of titles such as Popeye, Donkey Kong and Donkey Kong Junior.

Physical Media

Two formats of physical media were developed for the SG-1000 series, ROM cartridges not unlike those of the Atari 2600, and Sega My Cards.

SEGA SG-1000 compatible Monaco GP Game cartridge
SEGA SG-1000 compatible Monaco GP Game cartridge

Although cards had some advantages, such as some of them being rewritable (similar to what we saw earlier with the Famicom Disc System), and all of them being smaller and less expensive to produce, they were hampered by their severely limited storage capacity compared to that of ROM cartridges. For comparison, cards had between 4-32KB of ROM whereas carts had between 16-512KB* of ROM. (NB – some sources quote 128K as the maximum).

As a result, the number of games released on cards – around 30 – was much lower than those on carts, which numbered around 76.

The SG-1000, SG1000 II, SC-3000 and the SC-3000H lacked card slots, as their design predated the cards. However, they could run these games via the Card Catcher peripheral, which plugged into the console via its cartridge slot.

The Card Catcher allowed the SG-1000/II to play SEGA My Cards


The SG-1000’s Joystick (SJ-200) controller was hardwired to the console and featured a small joystick and two buttons located on either side of the controller. As with other hardwired controllers, if it broke there was no easy way to fix it.

SEGA SJ-200 controller
SEGA's first home system controller the SJ-200. It was probably quite uncomfortable to hold.

A second joystick controller could be connected via the then ubiquitous 9-pin port, also found on the 8-bit home microcomputers. However, I suspect it differed from the home micros in its implementation, with each button used for separate inputs, obviating the need for ‘up-for-jump’.

(NB – I’m basing this assumption on the later Master System which used a 9-pin connector but had separate ‘jump’ and ‘fire’ buttons. Feel free to correct me if I’m wrong)

Later, an extension cable was released that replaced the hard-wired controller. This allowed the use of plug-in controllers.

Allegedly, the SJ-200 was unresponsive and suffered from build quality issues. To rectify this SEGA went on to release the much improved and more conventionally designed SJ-300.

SEGA SJ-300 Joystick
The better designed and better made SJ-300 joystick

SG-1000 MK II

SEGA released the updated SG-1000MK II in July 1984. Its chip-set remained the same, however, its form factor was changed significantly. The expansion port was moved to the front of the unit for a mo