Even by the standards of rural Japan Kamiura is a quiet place but it takes a while to realise the full extent of its strangeness. The abandoned houses are the first sign. A bare field lies where there used to be a school but it is only after several miles that you notice the people.

The fishermen tending their boats, the farmers in the fields and the housewives gossiping in their gardens: all of them are elderly. You can drive for miles without seeing a young face. For Kamiura is at the epicentre of rural Japan's population crisis - one of tens of thousands of villages threatened with extinction.

A government survey last year listed 62,000 “communities on the edge”, where mass migration to urban areas had robbed them of the young, leaving behind only the old and the very old. These are places where parents in their nineties are cared for by offspring in their seventies, where schools are closing because they have run out of children and where the bored-looking lads slouching round the streets are not teenagers but disaffected septuagenarians.

A disproportionate number are in Hokkaido, the northernmost of the main Japanese islands, where Government statistics conclude that 9 per cent of all communities are endangered. The Government estimates that a third of these will have vanished within ten years, and few are closer to the edge than the village of Kamiura, 50 miles (80km) from the G8 venue at Lake Toyako.

A generation ago it was a busy fishing village of 10,000 where boats from across Japan docked for maintenance and refuelling. Now it is an eerie town of 2,000 people, four out of five of them old-age pensioners, and a quarter of them aged over 75. Every few yards is an abandoned house or fishing boat. Two months ago the senior high school closed after dwindling to just six pupils.

The Young Men's Association, which used to hold an annual athletics meeting at festival time, was disbanded two years. “It's so melancholy compared with my young days,” says Mitsuruhiro Ono, 71, who still goes out every day at 3am in his octopus fishing boat. “There used to be so many people passing by in front of the house, and the whole town was crowded with people. Compared with those times I have a lonely feeling.”

It has become impossible to ignore the collapse of the rural heartland in the past ten years but it has been going on for decades and for complex reasons. Partly it is a function of increased life expectancy and record low birthrates - the old routinely living into their eighties and nineties, the young having fewer children. Partly it is because of the increased expectations of consumer choice that affluence and education bring - the disinclination among the young to live in a village in which the nearest video shop, let alone cinema, is an hour's drive away.

Above all, it is a function of local economics and the dwindling of the rich fishing for sea urchin, abalone and salmon, which made the villages wealthy after Hokkaido was settled as the northern frontier territory of Japan in the 19th century. Overfishing and a slump in prices have made a dangerous and difficult activity less attractive than ever. So the local government has resorted to paying the young to live here.

The government of Setana Town, of which Kamiura is part, offers one million yen (£4,700) to local children who take over their parents' businesses, and double that to outsiders who come in to settle. They also subsidise asthmatic children from all over Japan who move to the town for its clean air. The thinking is that the children may bring their parents and that some of them may decide to stay.

In the three years since the scheme was introduced, 15 locals have been induced to stay and five newcomers have settled.

“The children leave, and who are we to tell them they must stay?” says Toshi Morita, 79, who lives alone between abandoned houses. “Eventually there will be no people here or just the likes of me.”

Times Recommends

• Rio Tinto four held as China prepares case
• Diplomats must keep heads down and trousers up
• When in Rome should one make like Berlusconi?