Read Leo Lewis' blog

For most of this year, the Tokyo market has been a deeply unhappy place: nervous, trigger-happy and volatile. There has been no compelling Tokyo story to propel shares, like their Shanghai-listed cousins, into the stratosphere, and no marrow-deep confidence to insulate equities from the US sub-prime panic.

But amid the murk there is one raging beacon of hope.

The gleam of Nintendo’s stock at Y70,000 per share is perhaps the most encouraging thing to happen to Japan since the end of the 1980s bubble. Not because it turns a video games console maker into Japan’s second most valuable company, and not because it makes Nintendo the best performing stock since the Black Monday crash in 1987.

It is exciting because investors are finally sinking money into a Japan-generated idea, rather than just a beautifully engineered product.

Certainly, Nintendo has physical products to sell: and second quarter results released today proved that it is shifting them in quite staggering volumes. Everyone wants the innovative Wii and a lot of very unexpected customers want the hand-held DS machine for the commute into work.

But that is not, in reality, why Nintendo is so deeply and alluringly sexy to the investment community. Nintendo has managed, almost uniquely in the Japanese market, to sell an idea – a dream that smart money wants to buy into.

On paper, it’s a fairly simple idea: that Nintendo has come up with a conduit that brings adults, en masse, into the world of video games. As that develops, runs the more complex logic, we are talking about expanding a market now worth tens of billions of dollars into a future one worth perhaps hundreds of billions.

True, Nintendo may not be the eventual winner of that trend – any more than AOL or Cisco have fulfilled their formerly imagined roles as stewards of the Internet. But for a while they were undoubtedly stewards of the dream.

What has happened to Nintendo’s stock is remarkable for several reasons – reasons that could, if they don’t fizzle out too soon – transform Japan’s moribund investment scene. Nintendo’s perception as a stock has effectively been “Google-ized”. Yes, there are extraordinarily healthy till receipts and shipment bills somewhere in the mix, but the buying focus is on enormous, jaw-dropping potential.

Previously – and perhaps most strangely given how many industries have been completely transformed by Japanese innovation – the Japanese market did not treat stocks like this as especially clever bets. Neither the Japanese financial media, nor many domestic investors, allowed themselves to be carried away by the power of thought. Japan is an exporter of cars, electronics, black boxes with wildly complicated tiny components, nuclear power stations and ultra-strong steel. Ideas – exciting visions of the future projected onto a particular stock – were for discussion, never investment.

Industries rich in potential have withered because of Japan’s investment blind-spot for companies peddling intellectual property, rather than physical things. The Japanese anime industry, for example, has been starved of investment capital because the Tokyo market has never believed that Japan can export the intangible.

Nintendo, riding high at Y70,000, suggests that finally, Japan may be ready to embrace the “Big Idea” stock as well as the master of miniaturizations. If it does happen, there are, in fact, plenty of young entrepreneurs waiting in Japan’s wings with big ideas to sell.

Times Recommends

• Minister in talks with Saudis to protect creditors
• Premier Inn hits back in £29-a-room row
• Bankers hit back at 'populist' bonus supertax