The impeccably dressed Tsunekazu Ishihara resembles one of Tom Wolfe’s Masters of the Universe: a hedge fund manager, perhaps, or a private equity partner. Only his achingly hip elfin hairstyle suggests that he rules a world inhabited by even weirder creatures.

As chief executive of the Pokémon Company, he runs a fantasy-animal franchise that generated more than $25 billion in revenues over the past decade. Not bad for a collection of video games, films, toys and trading cards whose target market, he says, is seven years old.

“The key to Pokémon’s success is that it is not a solitary experience,” Mr Ishihara, 49, explains. “Since the first title in 1996, we have designed video games for people to play together. New technologies, the internet, will make this stronger.”

The sales figures back him up. When the first Pokémon game (the name is a contraction of “Pocket Monster”, the first that title Mr Ishihara produced) emerged, its meteoric rise, first in Japan and then worldwide, looked to have all the trappings of a fad. Now, having sold more than 165 million units, it looks like an unstoppable juggernaut, albeit one steered by nearly 400 cute, made-up monsters.

The latest Pokémon titles, Diamond and Pearl, were the fastest-selling in the series so far, moving five million copies in Japan in their first three months. They have benefited from the runaway success of Nintendo’s handheld DS console, for which they were developed and which has achieved global sales of 40 million, twice the level of Sony’s rival PSP.

Building on that base, nearly two million copies of Diamond and Pearl were sold in the United States in April, lifting the titles to the top two slots in the nation’s games charts. They hit Europe this month.

The numbers speak to the endurance of a format first conceived by Satoshi Tajiri, the Japanese games guru, which has not changed significantly in a decade. “We are always looking for things that will be accepted on a worldwide basis, activities such as collecting insects or looking after animals, things with universal appeal,” Mr Ishihara says.

And so, in the latest titles, players again take on the role of a young Pokémon trainer who is granted a fledgeling monster as a friend and rival.

The pair compete to top the trainer charts and collect information about Pokémon species on the way.

There is, however, a twist – necessary, Mr Ishihara says, to keep Pokémon’s increasingly tech-savvy audience engaged. “Our mission is not only managing the licensing business, but to constantly think of ways of expanding and developing the content,” he says.

Mr Ishihara’s favourite game as a child was shogi, the Japanese version of chess that he played with his father. Fittingly, 40 years later, as he surveys the $30 billion-a-year video games market, he is still thinking several moves ahead. His focus now is on connecting hardware as much as youngsters.

The DS device has a wi-fi connection that taps Pokémon into the web. In the 1990s, Pokémon cards were traded in playgrounds. They still will be in the future, Mr Ishihara predicts, only they will be digital, not cardboard, and swapped wirelessly between children in different continents. “A player in Japan can already communicate with a player in the UK.

This is something we are very excited about,” he says.

Future versions of the game, Mr Ishihara adds, will build on the internet telephony features already inside Diamond and Pearl. A portfolio of Pokémon websites, including educational tools aimed to entice parents as much as their offspring, have also been added to the mix.

Pokémon will soon also be available for Nintendo’s groundbreaking Wii console, which has won plaudits for its “magic wand” controller and which is designed to be hooked up to a television. When Pokémon Battle Revolution is released this year, it will be the first title that allows players to link the Wii and the DS.

In the last generation of console wars, Nintendo, which part-owns the Pokémon brand, came a poor third behind Microsoft and Sony. This time it is more than holding its own against Sony’s handheld PSP, its big brother the PlayStation 3 and Microsoft’s Xbox.

“First and foremost we design Pokémon with the hardware in mind,” Mr Ishihara says, reaffirming his loyalty to Nintendo. “We have no plans to make a multi-platform game.”

He refrains from making it explicit, but Mr Ishihara appears to dismiss the PS3’s brawn (Sony’s platform easily out-muscles the Wii in terms of computing power). Again, the sales support his argument: the latest estimates suggest that the Wii is outselling the PS3 by five to one in Japan.

“The days of us trying to compete with matters such as better graphics are over,” he says, suggesting that Nintendo’s recent return to basics ties in with Pokémon’s long-held ethos: the constant reinvention of the lowest common denominators of play.

“Nintendo and Pokémon do not want to compete in terms of technological power,” he says. “We will win in terms of our players’ experiences.”

Eureka moment that set Tajiri loose

Pokémon’s eureka moment came in 1991, when Satoshi Tajiri, the creative genius behind the franchise, first set eyes on Nintendo’s new handheld console – the GameBoy. It was, Mr Tajiri, below, said later, the moment when “everything clicked”.

The co-founder of the cult magazine Game Freak (the group now owns about a third of the Pokémon brand), Mr Tajiri was well known to Tokyo’s gamers. Japan’s manga comic and animé film scenes each fed into the Pokémon look.

However, the key inspiration, he claimed, was the way in which two GameBoys, in the days before the internet, could be linked via a cable. People could play against each other, rather than against an arcade machine.

It is exactly the ethos that Nintendo is expoiting now with its DS and Wii machines.

At Nintendo, he met Shigeru Miyamoto, his mentor and the legendary creator of Mario. In 1996, the first Pokémon title was released, based, like those that followed, on Mr Tajiri’s childhood expeditions collecting insects. As Pokémon fever swept the globe, he was lauded by Time magazine as the one man brave enough to design a video game “in which nobody dies.”

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