A simultaneous twitch of 43 face muscles, a sudden flood of endorphins and maybe a momentary flash of teeth: to most of us, it's just a smile. To Japan, it’s an industry worth hundreds of billions of yen a year.

The business of making people smile - or exploiting the spending patterns of those who already are – has emerged as a surprise priority for large sections of corporate Japan.

Overnight an economy that once espoused the value of limited displays of emotion has shifted tack. “Smiling schools” have begun training executives how to make their grins as convincing as possible, and a book on the judicious use of smiling to close business deals has become a bestseller.

Towering over the whole smile industry is Yoshimoto Kogyo – the talent agency that represents most of the top comedians and has an effective monopoly on every gag uttered on television. The company has invested in the academic study of smiles and laughter – a discipline pioneered by Yoji Kimura, a Professor of Sociology at Kansai University and chairman of the Japan Laughter Institute.

Professor Kimura believes that he is months away from unveiling a machine that will reveal how funny we actually think a joke is, irrespective of how much we smile or laugh at it.

To technology companies such as Sony and Olympus, a corporate focus on smiling has paved the way for a new generation of digital cameras. Millions of yen have been diverted from research and development budgets into designing software that recognises a toothy grin. Within the past few weeks both companies have released cameras that automatically take a picture when the person in the frame cracks a smile.

Sony, which sells the device for about £200, has retooled its production line to incorporate the new software and plans to produce 35,000 “Smile Shutter” cameras a month for Japan alone. Camera companies that do not have the feature are scrambling to make the necessary investment.

The medical devices company Omron has grander ambitions. This month it released details of “Okao Vision”, which will not only measure the physical extent of a smile, but also its quality.

Koichi Kinoshita, the project’s supervisor, said: “We have had huge interest in this software from across Japanese industry: shops, hotels and restaurants are all interested in acquiring it so that staff can train and improve the quality of their smiles.”

Yoshihiko Kadokawa, meanwhile, offers a more human training regime. His smile consultancy educates the retail industry on how to increase profits with smiles. His hundreds of clients take his theories very seriously.

He said: “Smiles are like bottled water and tea – things that, in the past, nobody expected to pay for but now realise they have to. People have come understand that the smile can serve as a lubricant in business, and companies have started to make it a key feature of their strategies.”

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