The Game Boy’s screen had no colour and no backlight, and it smeared anything that moved quickly. Its rivals had colour. Nintendo launched the Game Boy to the West at the Consumer Electronics Show in Chicago in June 1989, and C&VG’s report from the show said Atari’s surprise announcement of a colour handheld, the Lynx, was “completely overshadowing” it. Yet by Nintendo’s own figures the Game Boy line sold 118.69 million, almost twice as many as the NES. It was cheap, it ran for a long time on four AA batteries, and outside Japan it came packed with Tetris.
Fast facts
- Launch: Japan, 21 April 1989. In American shops with Tetris by the autumn of 1989. Britain, September 1990, at £69.99 with Tetris.
- Designed by: Nintendo R&D1, the department led by Gunpei Yokoi.
- Processor: a custom 8-bit chip that Nintendo describes only as “customized for DMG/CGB use”, with the display controller, sound circuits, timer and DMA controller built in.
- Speed: 1.05 MHz “system operating frequency” in Nintendo’s terms, from a 4.1943 MHz oscillator.
- Display: 160×144 dots, four shades of grey, 59.7 frames a second.
- Sound: four sound generators mixed to two outputs, which made stereo possible through headphones.
- Power: four AA batteries.
- Sales: 118.69 million for the Game Boy line, including the Game Boy Color, by Nintendo’s figures.
A Game & Watch that took cartridges
David Sheff’s description in Game Over is that Yokoi’s 45-strong team “married the NES and Game & Watch”. Like the NES, it played interchangeable cartridges; like Yokoi’s Game & Watch handhelds, it was small and ran on ordinary batteries, with the same cross-shaped D-pad. When C&VG got one in July 1989, it measured the console at 9×15 cm and described a “Nintendo-style console in a bijou case”, with a black-and-white screen “similar to those found on tiny portable tellies like the Sony Watchman”. The reviewer found “absolutely no eye-strain involved using it”.
Accounts differ on who decided against colour. Sheff says it was Nintendo’s president Hiroshi Yamauchi, for cost and battery life; Retro Gamer reports a rumour that Nintendo’s executives pressed Yokoi for a colour screen and he held out. Both describe the same trade-off. The machine that shipped had a monochrome LCD made by Sharp, and developers had to work around its blur. “You didn’t want lots of the screen to have a lot of detail that was moving continuously,” Rare’s Chris Sutherland told Retro Gamer. “Objects like bullets had to be made larger, or with significant outlines so that players could more easily spot them.”
Tetris and the launch
Minoru Arakawa, who ran Nintendo of America, had seen the Game Boy prototype in 1987. When he played an arcade Tetris at a trade show in June 1988, he had his engineers make a version for the prototype, and decided “We must have this game.” Nintendo then went to Moscow for the handheld rights. In its July/August 1989 issue, Nintendo Power told readers that each Game Boy would come with stereo earphones, a Video Link cable and a Game Pak: “Which game? Better hold on to something! It’s Tetris!!!” Tetris was packed in everywhere except Japan.
The first sales were quick. Sheff reports 200,000 sold out in Japan in two weeks, 40,000 sold on the first day in the United States, and a first American shipment of 1.1 million. Retro Gamer gives 300,000 on the first day in Japan. The American price was $89.95 according to ACE, or $100 according to Sheff. Yamauchi had predicted 25 million in three years; Sheff counted 32 million sold worldwide by the end of 1992, with nearly half the players in the West being adults.
Britain waited. ACE expected a launch at the Earls Court Toy Fair in January 1990, but through the summer the Game Boy was only available as a grey import. The Games Machine reported the official launch for September 1990, “under £100”, when the Lynx was already on sale at £179.95. In October ACE listed the Game Boy at £69.99 with Tetris.
The processor
Nintendo’s manual never names the processor’s maker or part number. It calls the chip one of the “ICs customized for DMG/CGB use”, with an 8-bit processor, timers, interrupts, a DMA controller, the LCD controller and the sound circuits on one piece of silicon. The Pan Docs community reference describes it as an “8080-like Sharp CPU”. To programmers who knew the Z80 it looked familiar but cut down. “At the Game Boy’s heart was a castrated Z80,” Jon Ritman, who wrote Monster Max for it, told Retro Gamer. “They had taken out a few useful features such as the 16-bit instructions and they had also removed most of the registers.” The Pan Docs reference notes that it has more in common with Intel’s 8080 than with the Z80: there are no IX and IY registers and none of the Z80’s ED-prefixed instructions.
The clock speed depends on what is being counted. Nintendo gives the DMG’s “CPU speed (system operating frequency)” as 1.05 MHz and an instruction cycle as 0.954 µs, derived from a “source oscillation” of 4.1943 MHz. Modern references, including Pan Docs, quote the 4.194304 MHz figure and count instruction times in oscillator ticks instead, four to each of Nintendo’s cycles. So a NOP takes one cycle in Nintendo’s tables and four in most modern ones. The machine runs at the same speed either way.
Drawing the screen
The picture is made of 8×8 tiles, like the NES’s. There is a scrollable 256×256 background, of which the 160×144 screen shows a window, and a second layer, the window, which is positioned by its own registers rather than scrolled with the background, and which suits a status bar. The manual’s table gives the limits:
- Tiles: 384 in video RAM, arranged as 128 for sprites only, 128 for the background only, and 128 that either can use. Rare’s Mark Machacek told Retro Gamer this was a “juggling act”: if every background tile were different, the tiles available would cover only a quarter of the screen, so games repeated tiles heavily and copied new ones in as a level scrolled.
- Shades: each pixel has a two-bit value, which a palette register turns into one of four greys. The background and window share one palette. Sprites have two palettes to choose from, but value 0 is always transparent, so a sprite draws with three shades.
- Sprites: 40 on screen, no more than ten on one horizontal line.
The CPU cannot always reach video memory. While the display controller is fetching a line, display RAM and sprite memory are locked; the program can write to display RAM during each line’s horizontal blank and during vertical blank, which the manual says gives “approximately 1 ms” of access. The screen draws 144 lines in 15.66 ms at 108.7 µs a line, then spends ten more lines in vertical blank, for a frame rate of 59.7 Hz.
Saving the batteries
Nintendo’s manual has a short section called “Power-saving routines for the main program”:
To minimize battery power consumption and extend battery life, inclusion of programs such as those shown below is recommended. During waiting for vertical blanking, halt the CPU system clock to reduce power consumption by the CPU and ROM.
The listing reads the keypad, runs the game logic, then executes HALT. That stops the processor’s clock, while the display, sound and timers carry on from the oscillator, until the vertical-blank interrupt wakes the program for the next frame. A game that finished its work early was expected to sleep for the rest of the frame rather than wait in a loop. The listing also puts a NOP after the HALT, “used to avoid bugs in the rare case that the instruction after the HALT instruction is not executed”.
Sound
Four sound circuits, as the manual describes them:
| Waveform | Extras | |
|---|---|---|
| Sound 1 | Quadrangular (pulse) | sweep and envelope |
| Sound 2 | Quadrangular (pulse) | envelope |
| Sound 3 | Arbitrary, from waveform RAM | — |
| Sound 4 | White noise | — |
Only Sound 1 has the sweep, which slides a note’s pitch up or down automatically, useful for effects such as jumps and lasers. Sound 3 plays a short user-defined waveform stored in 16 bytes of waveform RAM. Each circuit can be sent to either or both of the two outputs; Nintendo Power promised owners Nintendo games “in true stereo for the first time” through headphones.
The family
The Game Boy was not replaced for years; it was reshaped around the same cartridges. Nintendo’s manual lists the Game Boy Pocket (21 July 1996), the Super Game Boy adapter for the Super NES (14 June 1994), the Game Boy Light (14 April 1998) and the Game Boy Color (21 October 1998). The Pocket was smaller and ran on two AAA batteries. The Color doubled the processor speed in its “double-speed mode” and ran older cartridges at the original 1.05 MHz. By then Pokémon, released in Japan in 1996, had given the platform what Retro Gamer calls a “second wind”. The Game Boy Advance, a new 32-bit design, followed in 2001.
Sources
- Nintendo of America, Game Boy Programming Manual version 1.1 (1999): introduction dates (p. 3); feature comparison (p. 16); CPU and LCD features (p. 18); sound, clock and instruction cycle (p. 19); HALT mode (p. 23); characters and shades (p. 48); screen timing (p. 56); STAT modes and display RAM access (p. 58); CGB operating speed (p. 127); power-saving routine (p. 128);
NOPandHALTinstruction tables (chapter 4). - David Sheff, Game Over (1993; GamePress edition, 1999), chapter 13, “From Russia with Love”: R&D1’s team, the Sharp LCD, the $100 price and Yamauchi’s prediction, the decision against colour, early sales, Arakawa and Tetris, 32 million by 1992 and the adult players.
- Computer and Video Games, July 1989: preview of the Game Boy (size, screen, four AA batteries). Issue 93, August 1989: show report on the Game Boy launch and the Lynx announcement.
- Nintendo Power issue 7, July/August 1989, p. 84: Tetris in the box. Issue 8, September/October 1989, p. 53: the Game Boy feature, stereo and the Tetris bundle.
- ACE issue 28, January 1990: the Game Boy launched at CES in Chicago the previous June; the planned UK launch; the US price. Issues 31–36, April–September 1990, console guide: UK release not before September, grey imports. Issue 37, October 1990: £69.99 with Tetris.
- The Games Machine issue 33, August 1990: UK launch in September, the Lynx at £179.95.
- Retro Gamer Collection volume 4, 2010, “Retroinspection: Game Boy”: the rumoured colour argument, 300,000 on the first day in Japan, Tetris as a pack-in outside Japan, the blurred screen (Chris Sutherland), the Z80 comparison (Jon Ritman), tile banks (Mark Machacek), Pokémon, the Game Boy Pocket.
- Pan Docs, “Specifications” and “Comparison with Z80” (web, secondary): “8-bit 8080-like Sharp CPU”; 4.194304 MHz; differences from the Z80. https://gbdev.io/pandocs/Specifications.html
- Nintendo Co., Ltd., Investor Relations, “Dedicated Video Game Sales Units”, figures as of 30 June 2026: Game Boy 118.69 million, NES 61.91 million (web). https://www.nintendo.co.jp/ir/en/finance/hard_soft/index.html
- Nintendo Co., Ltd., “Company History: Nintendo Milestones”: Game Boy Advance (2001) (web). https://www.nintendo.co.jp/corporate/en/history/index.html