Using a mobile to buy items from a vending machine is a technological match made in heaven for the Japanese, writes David McNeill

For millions of Japanese like 22-year-old Kai Ishii, the day begins with a quick canned drink on the way to the train station. "When I was a student in the UK I really missed vending machines," says the white-collar worker. "They're a lot easier than running around before work having to find a store."

Throughout the day, it is quite possible for him to get all he needs without having to interact with another person: subway tickets, beverages, bento lunch boxes, noodles and rice balls, cigarettes, toilet paper, beer and batteries. This is, after all, a country that boasts the highest concentration of vending machines on the planet - a staggering 5.6 million, or one for every 20 people.

Over the years in Japan there is little that has not appeared behind a coin-operated glass display case: ice, eggs, pet beetles, umbrellas and in one brief but bizarre boom, used high-schoolgirl panties.

Nothing is safe from the machine. In the days when flesh-and-blood humans exclusively staffed Japanese love hotels, bashful couples stood by the reception as a liver-spotted hand slid a key out from beneath a curtain and a croaky voice announced a room number. For some, being served by granny was a libido-killing moment. But punters are increasingly spared such embarrassing encounters. A push-button computer panel displays vacancies and a female-voiced vending machine inside each room times the love-making session while automatically locking the door. The only way out is to pay the machine, or start a fire.

"I prefer this way because it's more private," says Yuki Nakamura (23), a regular visitor with her boyfriend to hotels around the west Tokyo area. "It used to make me feel uncomfortable if I had to see the person behind the counter. Besides, machines don't make mistakes the way people sometimes do."

In the future, Yuki may not even have to carry money on her date. Several firms are working on a mobile phone-operated payment system that will charge the cost of purchases to her monthly phone bill.

Convenience, service, attention to detail and smart technology; this is what for some makes Japan the template 21st-century society, a country that struggles like no other to dull the friction of modern life and cherishes Sartre's dictum, "hell is other people". It is no coincidence that Japan has embraced the vending machine, which last year clocked up sales of about 7 trillion yen (€49 billion), according to the Japan Vending Machine Manufacturers Association, larger than the entire GDP of several small countries.

Few places here are more than a short walk from the humming neon box selling everything from rice to porn: country lanes, forests, beachfronts; even the top of Japan's national icon, Mount Fuji. Vandalism is rare, and the machines are invariably well stocked, sometimes with up to 30 different shrink-wrapped, canned or bottled products.

Engineers see the electronic vendor as one of the solutions to Japan's looming population crisis. With 19,000 fewer Japanese born in 2005 than the previous year, the machine is increasingly playing the role of service worker that in other countries is performed by immigrants. Some machines have even been programmed to talk in "warmer" local dialects such as Osaka in a bid to humanise them.

The vending box has been around for 100 years but exploded in popularity after the introduction of 100-yen coins in the 1960s. So ubiquitous are they today that it is easy to overlook the clouds that have gathered over the industry.

The industry is an environmental nightmare, spewing out millions of cans and plastic bottles, and tons of coolant gases, and consuming the equivalent of more than the output of a one-megawatt nuclear power plant every year. And Japan's 620,000 cigarette machines - 40 times the US figure - are blamed for fuelling the epidemic of underage smoking in a country with the fourth-highest smoking rate in the world. A recent government survey found that more than two-thirds of high-school children buy their first cigarette from a machine.

This being Japan, high-tech help is at hand. Coca Cola Japan, which owns almost a million vending machines, has spent a fortune developing a low-emission, eco-friendly model and says it will phase out older machines by 2020.

In a bid to head off growing pressure from the World Health Organisation, meanwhile, the Japanese tobacco industry (which is heavily backed by the government) has developed an ID-card system for purchasing cigarettes. The system has gone on trial on a remote island off the coast of Kyushu, which has about 170 machines catering to 8,000 gaspers.

The results are mixed - arrests for underage smoking down by just seven in a year of trials. "It won't stop youngsters who really want to smoke because they can always get a hold of their parents' ID cards," says Kenichi Sato, who frets about the teenage boys who gather around the machines outside his convenience store in Sagamihara City, west of Tokyo.

But some in the industry are focusing on the big prize: finding a way to link vending machines with almost 90 million Japanese cell-phones. Mobiles are already widely used to buy concert tickets, book restaurants and scan at ticket barriers in train stations and by 2008, about 40 million Japanese may be using them as part of what's called the cash-less society, according to the think-tank Japan Research Institute.

Coca Cola Japan took the lead in the race to the future by launching a pilot scheme four years ago allowing mobile phone subscribers to buy directly from 2,100 strategically placed machines.

The phone is swiped over an electronic reader like a supermarket barcode check-out, and the customer is later billed for the purchase. Organised with telecom giant NTT, the service has taken off, and Coca Cola plans to convert 20 per cent of all its vending machines within three years.

"Mobile-phone purchasing is the wave of the future," says Takashi Kurosaki, secretary general of the Japan Vending Machine Manufacturers Association. "We expect this to grow and grow."

Vendors love the system because they can track the preferences of consumers.

"It allows us to send information to the consumer on their cell phone such as samples of new products, and we can also learn what sort of products they like," says Coca Cola spokesman Kota Takasugi.

Anything that increases convenience in this busy, gadget-mad country is likely to get the thumbs up from consumers, especially youngsters who have grown up with vending machines and already use mobile phones like a third hand.