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With hands clasped neatly in her lap and iron-grey hair combed straight back, Haru Matsumara, 100 last April, explains the secret of her long life.
"I do like milk but I could not afford it when I was young," she says. "I have never eaten a lot of meat. I like traditional foods, fermented soya beans and fried bean curd."
It is not much to account for a century of existence, most of it lived in rude good health. But Mrs Matsumara, the oldest resident of the Sunflower care home in the Japanese city of Kyoto, mentions one other vital ingredient.
"I have a happy-go-lucky nature," she adds. "Even if I am worried, I get a good night's sleep."
Her large, soft face with its skin like parchment breaks into a smile. Her demeanour can be summed up in one word: cheerful. It is a characteristic often found in the extremely old.
Jeanne Calment, the oldest person ever recorded, died at Arles in south-western France in 1997, at the age of 122. She attributed her longevity to an ability to "keep smiling".
Japan, long renowned as a society which venerates the elderly, boasts 25,000 centenarians. However, it is no longer smiling at its achievement. Tomoji Tanabe, 112, was confirmed as the world's oldest man in June and presented with his certificate by Guinness World Records last week.
He apologised for his longevity, joking: "I have been around too long. I am sorry." His pessimism is understandable. Japan has the fastest ageing society in the world and one in five Japanese people is over 65. That proportion is projected to rise to 40 per cent by 2055.
At the same time, the birth rate is falling because of the same social pressures facing Western nations - later marriages, more women going to work and the trend for smaller families.
Japanese women now have an average of 1.26 children in their lifetime, well below the replacement rate. As a result, Japan's population is projected to fall from its present 127 million to 90 million by 2055.
No country in the world has faced a challenge on this scale. As its elderly population grows, medical and pensions costs are surging but the number in the labour force who pay taxes to support the country's welfare system is falling.
Thanks to Japan's long economic recession, which began with a stock market crash in 1989, the Government debt is already the highest among developed nations.
Ed Wright, the first secretary for science and health at the British Embassy in Tokyo, said: "It's a tough time to be 50 in Japan. People sold themselves to their companies in the 1970s in anticipation of a comfortable retirement.
"Now they have fears about job security, house prices, which are worth a quarter of what they were. The stock market, which peaked at 40,000 points in 1989, now stands at 16,000, having been down to 7000.
"They also worry about health insurance."
The ageing juggernaut about to hit Japan is heading down the tracks in all developed countries, which is why the world is watching closely to see how the Japanese cope.
The Government has responded on three fronts - with a new insurance scheme for the elderly, a strategy to stem the rise of obesity and other lifestyle diseases, and the introduction of hefty patient contributions to curb demand for healthcare.
Life expectancy in Japan has been rising for 160 years at a steady pace of two years every decade, and is now 85.52 years for women and 78.56 years for men.
In its World Health Report this year, the World Health Organisation declared that Japanese women were once again the health champions of the planet, living longer and healthier than men and women in all 193 countries. This has been attributed to a combination of the right genes and a diet based on rice, vegetables and fish.
The tropical Okinawan islands in Japan's extreme south-west are home to more than twice the national average of centenarians.
Their traditional diet is deemed even healthier than that of mainland Japan, with more edible seaweeds, higher protein content and more local produce rich in antioxidants, as well as a more relaxed lifestyle.
In addition, the Okinawans have a cultural habit of calorie control called hara hachi bu or "eat until you are 80 per cent full".
Consequently, the Okinawans consume fewer calories and are among the leanest and fittest people in the country. But the islanders' famed good health is now under threat, as it is in the rest of Japan, from the adoption of Western lifestyles.
In Tokyo, McDonald's, KFC and Krispy Creme doughnuts have pushed out the sushi bars. When a Krispy Creme opened in the city's Shinjuku district, people queued around the block to sample one of the calorie-laden doughnuts, and an estimated 10,000 people visited the branch in its first three days.
The strong tradition of families eating an evening meal together is breaking down in cities where two-hour commutes are common and workers grab a calorie-laden snack as they leave their offices, rather than wait to eat at home.
At Mukou City Primary School on the outskirts of Kyoto, a smart establishment for the children of professional parents, pupils eat a healthy lunch of fish, clear soup with tofu and aubergine with minced meat. But asked to name their favourite dish, they chorus: "Western food".
"When we go out, it is always to McDonald's," says Jackie, 11.
In 2000, a long-term-care insurance scheme was launched to which everyone over 40 is required to contribute an average of $55 a month.
The fund is used to pay for care for the elderly, whose needs are ranked on a scale, either in their own homes or in care homes such as the one occupied by Mrs Matsumara.
But the scheme has already run into difficulty as demand has vastly exceeded supply.
Hence, the premium has been raised 40 per cent in five years and elderly applicants have been re-classified to a lower dependency level in order to reduce their benefits.
The changes have raised doubts about the viability of the scheme. In a further effort to restrain costs, the Government has announced that, from next year, health insurers will be required to offer medical checks to anyone over 40. The aim is to reduce the burden of chronic diseases such as diabetes, which affects almost 20 million Japanese.
Staff health checks introduced by Mitsubishi are claimed to have reduced risk factors by 30 per cent after identifying lifestyle problems.
On a third front, the Government has massively increased the level of patient contributions called "co-payments" to the costs of healthcare.
All Japanese have health insurance provided either by their employer or by the Government and are free to visit any doctor or hospital they choose.
Co-payments, originally set at 10 per cent of the cost of treatment, were raised to 20 per cent in 1997 and to 30 per cent in 2003, with a cap of 70,000 ($817) a month.
Experts say the pressures on Japan's health service will soon be felt globally.
Karol Sikora, a cancer specialist at Imperial College, London, joined a study tour of the country organised by the British private health insurer, Western Provident Association.
He said: "There is a global crisis affecting healthcare systems driven by the ageing of the population, technical innovation, increasing consumerism and societal change.
"Social solidarity is dead, the role of women is changing and being a care-giver is a low-rated job.
"Japan does seem to be getting value from its health service but politicians are stuck with an ageing population that pays very little tax, putting an increasing burden on the young.
"You can't raise taxes beyond a certain level, which means some form of co-payment will be needed.
"What we are seeing here is the shape of things to come everywhere, as populations age."
- Independent
