Rikuzentakata, like many towns on Japan's rugged north-east Pacific coast, was in decline even before last year's tsunami killed 1 700 of its 24 000 inhabitants and destroyed most of its downtown buildings. With two-thirds of the remaining residents homeless, mayor Futoshi Toba questioned whether the town could recover. Damage to infrastructure and the local economy, he said, would force people to move away to find jobs.

Sixteen months later, the town is trying to rebuild in a way that Toba says will reinvent the region and provide a model to overcome obstacles that have hobbled the Japanese economy for more than 20 years: the fastest-ageing population in the developed world, loss of manufacturing competitiveness to China and South Korea and reliance on imported fossil fuels.

Rikuzentakata is part of a government programme to create one of the country's first so-called ecocities.

These towns will be smaller and more self-sufficient and will lower costs through technology and create new jobs in renewable energy to replace those lost to the decline of agriculture and fisheries.

Toba says Japan must address the depopulation of rural areas that has coincided with agriculture's shrinking role in the broader economy - from about 6 percent in the 1970s to 1.4 percent today - and it must do so as soon as possible.

"It's a race against time," he says.

Ecocities can lead the way, says Hideaki Miyata, an engineering professor at the University of Tokyo who is advising local officials on the project. "We can provide a solution for Japan's super-ageing society," he says. "Younger people were already leaving these cities, but what we're planning to do here will provide new jobs and factories."