Sega Game Gear

Sega’s advertising for the Game Gear did not bother to be polite. Retro Gamer recalls one advert calling the Game Boy’s picture “green spinach colour”, and another claiming that “if you were colour-blind and had an IQ less than 12, then you wouldn’t care which portable you had.” Sega’s handheld had a backlit colour screen and a palette of 4,096 colours, and Nintendo’s had four shades of grey.

Inside, it was a Master System. Retro Gamer describes the design, codenamed Project Mercury, as “essentially a miniaturised Master System with a more powerful video processor”, which meant Sega’s home games could be converted quickly. The price of the colour screen was power. The Game Gear took six AA batteries, and Compute!’s tests in 1991 got about four hours from a set, against 24 for the Game Boy.

Fast facts

• Maker: Sega.
• Released: 6 October 1990 in Japan (¥19,800); April 1991 in the United States ($159.95 with Columns); 1991 in Britain (£99.99).
• CPU: Zilog Z80A at about 3.6 MHz, the Master System’s processor.
• Screen: 3.2-inch backlit colour LCD (Compute! measured 3.5 inches). The game area is 160×144 pixels, with 32 colours on screen from a palette of 4,096.
• Sound: four channels (three tone, one noise), in stereo through headphones.
• Power: six AA batteries; three to five hours of play.
• Games: its own cartridges, and Master System cartridges through an adaptor.

A Master System with a new mode

The community documentation at SMS Power!, written from tests of the hardware, sums up the video chip in one sentence:

The Game Gear VDP is identical to an SMS2 VDP except that: It does not initialise the palette for TMS9918a modes. It includes an additional Game Gear mode (enabled by the cartridge hardware) where: the palette depth is increased from 6 to 12 bits per pixel; the displayed screen area is reduced to just the central 160×144 pixel section.

Two things follow. The colour improvement is large: each palette entry has 4 bits each of red, green and blue instead of the Master System’s 2, so a colour can be one of 4,096 instead of one of 64. And the Game Gear mode is switched on by the cartridge, through the connector. A Master System cartridge in an adaptor leaves it off, and the machine then behaves as a Master System.

The Game Gear screen is a window onto a full-size Master System screen, not a smaller screen, and the edges show it. SMS Power! lists the consequences for programmers:

• the top two rows are off the screen, so the Master System’s option to stop them scrolling sideways has no visible effect;
• the leftmost column is off the screen, so the option to blank it is pointless;
• “the sprite limit can still occur for off-screen sprites”.

The last is the Master System’s limit of eight sprites on a line, used up by sprites the player cannot see. A Game Gear program has to keep sprites out of the parts of the screen that are never displayed.

Fitting a 256-pixel game on a 160-pixel screen

The LCD is a Citizen UC-320 of 160 × 146 dots, two rows more than the game area. In Master System mode the full 256-pixel picture has to fit it, and SMS Power! describes how the hardware scales it. It drops the first and last eight columns to leave 240, then maps every three pixels onto two “using sub-pixel mapping”:

[RGB]1 [RGB]2 [RGB]3 = [RG1B2] [R2GB3]

The red, green and blue parts of three source pixels are shared out across the panel’s own coloured sub-pixels, so less detail is lost than if a whole pixel were thrown away. Vertically, the scaler skips every third row. A standard 192-line Master System game is padded with border above and below and comes out “letterboxed”. A game using the taller 224-line mode fills the screen. The 240-line mode is not supported and freezes the display until the machine is switched off.

Stereo that the speaker ignores

The Game Gear’s sound chip is the Master System’s four-channel generator, with one addition. Writing to port $06 sends each channel to the left, the right or both, one bit per channel per side. SMS Power! adds a warning:

Note however that this only affects the headphone output. The built-in speaker is unaffected … If a channel is set to mute both sides, this has no effect on the speaker. Thus, don’t use this to mute the sound.

A channel silenced in both ears still plays through the speaker, so a program has to turn a channel’s volume down to silence it.

Launch and price

The Game Gear went on sale in Japan on 6 October 1990 with Super Monaco GP, Columns and Pengo. C&VG reported in December 1990 that it cost about ¥19,800 in Japan (about £79), with games at ¥3,500, while British importers were charging £200 to £250. The magazine also described the add-ons Sega had planned, including a TV tuner, a link-up lead and a cable for a car’s cigarette lighter.

In America the Game Gear reached a few markets in April 1991 and the whole country that summer. Compute! priced it at $159.95 with Columns and preferred it to the Atari Lynx: the screen was “sharper and brighter under more varied light conditions” and Sega “has more developers in its stable”. In April 1991 C&VG reported that Virgin would launch it officially in Britain that summer for £99.99, with the TV tuner to follow. The magazine still thought the Lynx had the better hardware and the Game Boy the more playable games, and called the tuner the Game Gear’s “ace in the hole”.

Six batteries

Compute!’s August 1991 comparison, averaged over “several alkaline battery sets”, gave these results:

Retro Gamer gives three to five hours, and calls the power supply the Game Gear’s most important compromise: the backlight that let it beat the Game Boy’s screen also emptied its batteries. Rechargeable packs and a mains adaptor became common accessories.

Games

Most Game Gear games came from Sega, and many from its Master System library. Retro Gamer explains that the design made conversion cheap: an unaltered Master System game could go into a Game Gear cartridge, and most of the work was recolouring the graphics for the larger palette and fitting them to the smaller screen. Columns was the pack-in, and Sonic the Hedgehog made what Retro Gamer called “a very decent debut” in a scaled-down 8-bit version, followed by sequels and spin-offs.

Sales and the end

The figures differ. Retro Gamer put the total at “over 8.5 million units” in 2005. Wikipedia, citing a Famitsu table, gives 10.62 million by March 1996, 1.78 million of them in Japan. The 2019 book SEGA Master System: a visual compendium calls it a “ten-million-selling” handheld. All of them put it well behind the Game Boy and well ahead of the Lynx and the TurboExpress.

Retro Gamer reports that Sega ended Japanese support in late 1996 as it turned to the Saturn. In February 2001, according to the same article, the American publisher Majesco, which had bought the rights, began selling a slightly modified “Core” model through Toys “R” Us at $29.99, but only two games were released before it stopped production. Sega returned to the machine in 2020 with the Game Gear Micro, a small Japanese model with four games built into each version.

See also

• Sega
• Sega Master System
• Game Boy
• Atari Lynx
• Neo Geo Pocket
• Columns