It all started with the case of Sogen Kato.
At 111 years old, Kato was thought to be one of the oldest people in a country that venerates the elderly and boasts a life expectancy that is among the highest in the world.
But in late July, police found Kato's mummified corpse in a bed at the home where he died — more than three decades ago. His 81-year-old daughter hadn't reported his death, and allegedly had pocketed more than $100,000 in pension payments, authorities said.
Within days, it was clear that Kato wasn't the only centenarian who wasn't exactly where Japanese thought he was, or even still alive. Officials now say that they are unable to account for more than 1,000 of the country's 40,399 listed centenarians. In addition, news reports have told of government officials who allegedly failed to log deaths in Japan's ubiquitous family registries, and old people who died years ago alone and unnoticed.
The revelations have been a shock for a country that pays special homage to its elderly, even dedicating a national holiday for them: Respect for the Aged Day.
But Japan is in the midst of broad changes in social attitudes and a prolonged period of economic stagnation. A number of traditional beliefs — including the wholesomeness of locally grown food, the safety of nuclear power plants and the sanctity of old age — are fraying.
Life expectancy here is 86.4 years for women and 79.6 years for men. By 2015, one in four of Japan's 127 million people will be at least 65. Many are asking who will care for the growing number of aged.
The answer used to be clear. It was expected that families would look after their elders, said Tsugumi Okuma, 69, who lives in the western city of Kyoto. For 10 years, Okuma cared for her bedridden mother, waking early, bathing her daily, and helping her in the bathroom, often in the middle of the night. Her mother died in 2008, at the age of 94.
"I used to think what I did was the norm," Okuma said. "But now it's clear that the family unit is disintegrating."
As a result, the government is being asked to do more. The top priority is finding out where those missing elderly are. The Health Ministry and local governments are conducting surveys, and other authorities are investigating whether family members of some are fraudulently receiving their pension payments.
Some centenarians who were thought to be missing have been tracked down in nursing homes. But complicating the search is the fact that more seniors are opting to live on their own in order to be more independent, not burden their families or be closer to friends. The National Institute of Population and Social Security Research estimates that 30% of Japanese 65 and older live alone, and that the figure will rise to almost 40% in the next two decades.
They're also increasingly dying alone, something that's become so common there's a term for it: kodokushi.
The thorough data that Japan keeps on its citizens should prevent many elderly people from falling through the cracks. It's not just tax, medical and pension records. The government also issues ID cards and requires anyone who moves to check in with local authorities.
And every person belongs to a family registry that documents marriages, births and deaths dating back generations. In theory, officials can dig up a rich paper trail on anyone.
But Japan also has tough privacy laws. Along with lax record-keeping and bad communications, those laws might have played a role in cities losing track of some of their elderly.
Kobe city officials initially reported 127 missing centenarians, one of the highest numbers across the country. They recently confirmed that 11 were living in nursing homes or with relatives, 17 were dead and 99 were no longer where they had been registered.
In neighboring Osaka, 63 of 809 registered centenarians, including a woman who would have been 123 years old, were unaccounted for, said Osaka official Kiyoshi Kozawa.
Not everyone thinks the onus should be on the government.
Last year, Shouji Oono, a 79-year-old with thick glasses and wispy silver hair, rallied elderly residents of an apartment complex in Yokohama to build a tighter community. They formed a nonprofit organization to watch over the 40% of residents who are at least 65 years old.
Nearly half of the seniors in the complex live alone. Many have been there since the apartments were built in 1964.
"We look to see if people are doing their laundry, have their lights on at night, that kind of thing," said Oono, who has lived on his own since his wife died 24 years ago. "We try to notice when somebody goes missing."
Last year, the government-funded housing agency that owns the land, Urban Renaissance, approached Oono's group with a proposal to install motion sensors.
The agency had noticed a sharp rise in the deaths of elderly residents living alone in the 700,000 apartments its owns. The idea was simple: A mix of government money, cutting-edge technology and old-fashioned grass-roots activism would help residents watch over the oldest and frailest.
In July, it installed sensors in 10 apartments; 70 more apartments will get them in coming months. By early 2012, the sensors are expected to be in as many as 1,000 apartments.
"We can't rely only on new technology or only on community groups. We need both," Oono said.
On a recent scorching afternoon in a neighborhood in northwest Tokyo, Yoshihisa Wakui and a colleague knocked on the front door of a two-story wood frame house.
Wakui leads a team from the city's Suginami ward that is trying to confirm the whereabouts of 252 centenarians. His records show that a 101-year-old woman lives in the house.
Wakui said they met the woman in a sitting room, and asked about her diet, her daily routine and her interests. Within half an hour they had left.
Not all visits go as smoothly.
"Do we respect the privacy of a person who wants to be left alone and is being looked after?" said Wakui. "Or do we wield authority and barge in so we can update our records? It's a difficult question to answer."
Hall is a special correspondent.