They would make for bizarre missing persons posters: "Unknown number of Japanese citizens. Distinguishing features, grey hair and facial lines. Aged at least 100. Last seen several decades ago."
Japan today launched a nationwide campaign to establish the whereabouts of its oldest residents after embarrassed officials in Tokyo discovered that a 113-year-old woman thought to have been the capital's oldest citizen had been missing for more than 20 years.
The revelation that Fusa Furuya's relatives have no idea where she is and that the house where she was supposed to have lived no longer exists has sparked feverish media coverage. It comes days after the corpse of Tokyo's supposed oldest man was found mummified more than 30 years after his unreported death.
Officials in the capital's Suginami ward attempted to visit Furuya, who was born in 1897, at an apartment in the city yesterday but were told by her 79-year-old daughter that she had never lived there.
The daughter gave them the address of a house in Chiba, outside Tokyo, where Furuya was apparently living with the daughter's estranged younger brother. Officials arrived at the address to find that the building had been demolished to make way for a motorway.
Furuya and her daughter were registered as having moved to Tokyo in 1986 but the exact date of the older woman's disappearance remains a mystery. Police are attempting to contact her son to establish her whereabouts.
The failure of the city's welfare office to maintain contact with its two oldest residents is an embarrassment for a country that prides itself on looking after its huge population of senior citizens.
Tokyo welfare officials said they had not directly contacted the pair for decades, despite having recorded their apparent feats of longevity. The city reportedly learned of the man's death and the woman's disappearance when they began updating records ahead of a national holiday held to show respect for the elderly.
It has since emerged that a search is under way for a 106-year-old man in Nagoya, while the Asahi Shimbun newspaper said three more centenarians had vanished.
The government said it would establish their whereabouts, and those of an unknown number of other centenarians, as Japan prepares to mark respect-for-the-aged day on 21 September.
"It is important for authorities to grasp the reality of where and how old people are living," said the health minister, Akira Nagatsuma.
Japan is home to 40,399 centenarians, including 4,800 in Tokyo, according to the health ministry. Each year, those who have turned or are just about to turn 100 receive a congratulatory letter and trophy from the prime minister.
The phenomenon of disappearing seniors hit the headlines late last month when police discovered that Sogen Kato, then thought to be Tokyo's oldest man at 111, had long since died.
His mummified corpse, dressed in long johns and covered with a blanket, was found 32 years after he retreated to his bedroom, telling his 81-year-old daughter and her 83-year-old husband that he wanted to become "a living Buddha".
"He was a very scary man," Kyodo News quoted one of Kato's grandchildren as telling police. "We couldn't open the door. He shut himself in the room without food or water."
Police arrested several members of the family on suspicion of abandoning a corpse and continuing to withdraw millions of yen in pension payments from his bank account.
"His family must have known he has been dead all these years and acted as if nothing happened," said Yutaka Muroi, a Tokyo metropolitan welfare official. "It's so eerie."
It is not the first time Japan has been found wanting regarding the welfare of its oldest citizens. After a similar case in 2005, involving a woman who hadn't been seen for 40 years, local governments were urged to update their records and found there were 52 fewer centenarians than previously thought.
The job of keeping track of the elderly is likely to become even more difficult. Japanese women have enjoyed the world's longest life expectancy – now a record 86.4 years – for the last quarter of a century, while men can expect to live 79.5 years.
Welfare officials complain that they do not have the authority to forcibly inspect the homes of centenarians if other members of their family object.