The first of the baby boomers are turning 60 this year - and the BBC is running a series of articles and interviews to mark the milestone. Here the BBC's Chris Hogg in Tokyo examines Japan's looming demographic problems.
They call it the 2007 problem here.
Japan's first generation of baby boomers born between 1947 and 1949 will retire next year. Together they represent more than 8% of the country's workforce.
Many of this first wave of boomers will retire at once because surveys suggest only about one in five corporations plans to provide jobs to those over 60.
So Japanese industry will lose the generation of highly skilled workers who helped drive Japan's recovery in the decades after World War Two.
"The baby boomers were the foot-soldiers of Japan Inc," says Prof Jeffrey Kingston from Temple University in Tokyo.
"They helped to build up Japan to become an economic powerhouse but sadly they also presided over the demise of Japan Inc when the recession hit in the 1990s."
Nonetheless today Japan's baby boomers enjoy a prosperity their grandparents could only have dreamed of.
They have become an important market, voracious consumers of cars, gadgets, appliances and other expensive goods.
They hold 10% of the total personal financial assets in Japan.
You might think then, that their imminent withdrawal from the workforce would worry businesses here.
Pull of the 'grey yen'
But some see the retirement of the baby boomers as an opportunity, not a threat.
Near Yamagata in rural Japan, north of Tokyo, the convenience store chain Lawsons has refitted a store to ensure it focuses on the needs of its older customers.
The countryside around the store looks green enough. But it is turning grey. Out here almost half the population is over 50.
Until recently, though, only 5% of them shopped at Lawsons. Like most convenience stores it tended to attract younger customers.
Business is up after baby boomers' needs were catered for
So the company changed tack to try to attract the baby boomers.
The idea was pretty simple. Sell more things like reading glasses or hair dye and more baby boomers will come into your shop.
The price labels on the shelves are bigger than normal. Some of the staff are older too. And there is an area for the customers to sit around and chat once they have finished their shopping.
It works. Already four times more baby boomers are shopping at the store than before the refit.
The way the demographics are going, that is good business according to the company's Chief Financial Officer Eiichi Tanabe.
"We are now trying to broaden our customer base," he says. "Japan's population is shrinking so the market is not growing. Shifting our customer base is an urgent priority if we're to prosper."
But what about the baby boomers themselves. How confident are they about their future?
Birth of a new life
Yutaka Shibata has worked for 36 years for the electronics firm Toshiba and raised two children.
Now at last he has the time to enjoy himself and do the things he enjoys, playing tennis, singing in the company choir, learning to cook and travelling.
"For us this is kind of the start, the birth of our new life," he says. "My former life as a salaryman was just too busy."
But he is uneasy too about what lies ahead. He and his wife, like many of their generation, nursed their elderly parents at home as they grew more frail.
Yutaka Shibata: Good life now, but worries ahead
But his children, who were raised in the US when he was sent overseas by his company, have now married and settled abroad.
"We cannot expect them to take care of us," he says. "When the time comes for us to need more care we will have to do some research to work out where we can go."
Yutaka and his wife Junko are both very fit, playing tennis every day and watching their diet, so the day when they will need more care seems a long way off.
For now they and many of the rest of their generation have the money and the time to make the most of their "second life" of retirement.
But further down the road life may get a lot harder, as the country struggles to look after growing numbers of elderly people, with fewer and fewer youngsters to care for them.
Grounds for optimism
So should Japan be optimistic or pessimistic about the retirement of the baby boomers?
The academic, Jeff Kingston, sees a reasonably bright future ahead.
"It will stimulate services like the medical industry, the travel industry, robotics to address the needs of the baby boomer generation."
"Young college graduates could find the retirement of the baby boomers means there will be more jobs for them, and the boomers' savings and generous retirement packages could stimulate a consumption boom."
"Their retirement will open up new opportunities for the younger generation."