Twenty years ago Japan's Nintendo Co. launched the Game Boy, the iconic handheld video game player that spawned characters from Super Mario to Pokemon and sold 200 million units worldwide.

When the Game Boy was first launched this week in 1989, Japan was enjoying its economic "bubble years," Madonna's "Like a Prayer" topped international charts, and Chinese students were just starting to mass on Tiananmen Square.

Video games had recently moved from the arcades into family homes. In Japan children were playing Nintendo's Family Computer or "Famicom" games on their television sets, and simple handheld games called Game and Watch.

But the Game Boy -- sold at 8,000 yen (80 dollars at today's exchange rate) -- was the first portable console with changeable game cartridges and marketed as "35 hours of games in your pocket with just four batteries."

"Children were so happy they could play on the train after school and before the inevitable evening crash courses," recalled Hirokazu Hamamura, head of Enterbrain, a publishing company on the gaming industry.

"If Nintendo beat its rivals in this field, it's because the company has spent decades in the universe of social gaming," he said.

Kyoto-based Nintendo started off in 1889 as a maker of card games and moved into toys in the early 1900s. In 1983, it launched the hit Famicom, called the Nintendo Entertainment System in the United States.

Nintendo "understood the young public, which was not the case for electronic groups like Sony, which targeted adults," said Hamamura.

Sony came up with the Walkman in 1979 but only launched a hand-held game console, the PlayStation Portable, years after the Game Boy.

The Game Boy -- first associated with games ranging from Tetris to the endless adventures of Pikachu and its Pocket Monsters friends -- has since then kicked off a revolution in gaming software.

"Video games played on television essentially revolved around fight games or a game between two players or against the console," said Hamamura.

"But with the Game Boy and Tetris, the types of missions began to evolve," leading to more diverse and sophisticated games such as Pokemon, he said.

Consoles of the Game Boy series -- which includes the pocket, lite and colour versions -- have since sold 118 million units, while the follow-up Game Boy Advance series sold 82 million consoles.

Twenty years on, Nintendo's portable consoles have grown up with their users. Nintendo in 2004 launched the dual-screen or DS portable console, which has since sold more than 100 million units around the world.

It boasts games such as the popular "Dragon Quest," but also study applications, restaurant guides, dictionaries and other functions. Some primary schools in Japan now use it to teach English and Japanese kanji characters.

"Nintendo has always preserved the same philosophy: entertaining the family," said Hamamura. "But in 20 years the company has also expanded its range of games with educational titles, which has turned adults into players."

Nintendo president and CEO Satoru Iwata reportedly said recently that "it's a grand vision to have every student at every school using a DS.

"It will take time and energy to reach that goal because the DS has been viewed by teachers as an enemy for a long time."