After Shigeru Miyamoto developed a love of puzzles, the “brain-training” software that has proved to be an international “killer application” on the Nintendo DS console was born.

He became interested in taking more exercise, and Wii Fit was created. He took up music lessons, and Wii Music was the result.

Now, according to sources at Nintendo, the games designer has been banned by the company from speaking publicly about his hobbies.

It's not that they are naughty, illegal or even nerdish, it's just that any glimpse inside his head could be worth billions. Particularly so now: the Wii still sells strongly around the world, but its successor is the talking point. Unfortunately, the only place where the discussion has any grounding is inside Mr Miyamoto's head.

Having managed to lure millions to games with the inventiveness of characters such as Zelda and Mario, it became Mr Miyamoto's hobbies that shifted gears for Nintendo in the next-generation console era. And as Nintendo's Wii games console approaches its second year, even the most fleeting insight into how Mr Miyamoto is spending his work or play-time is creating huge interest.

In short, the gaming and investment communities are wondering which of his current pastimes will be translated into a virtual rendition that will attract millions of sales five years from now.

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