Yeah right. There have been more cases of age related fraud in Japan than anywhere else on earth.

One such famous case is Sogen Kato:

https://en.wikipedia.org/wiki/Sogen_Kato#Aftermath

How they are doing that?

At least in official documentation. A lot of areas in Japan with large numbers of unusually old people also have an equivalent deficit of people a decade or two younger, and had birth records lost in WW2 bombing, suggesting that what’s happening is people taking advantage of this to claim their pensions early.

I wonder how many of them are pension fraud?

The final paragraph:

...some families may have tried to hide the deaths of elderly relatives in order to claim their pensions.

IIRC NHK (via maybe Japanology?) did a piece on this a few years ago, and the number of centenarians whose death had been hidden to keep their benefits flowing was staggering.

Though I think they chose the low hanging fruit: those aged 110 (or 120?) and higher.

That's a lot of years in aggregate

or many ate likely lying

https://fortune.com/europe/2024/12/14/are-blue-zones-myth-extreme-aging-pension-fraud-century-old-lies/

But Saul Justin Newman, a researcher at University College London’s Centre for Longitudinal Studies, told AFP that most extreme old age data “is junk to a really shocking degree”.

Newman’s research, which is currently being peer-reviewed, looked at data about centenarians and supercentenarians — people who live to 100 and 110 — in the United States, Italy, England, France and Japan.

Contrary to what one might expect, he found that supercentenarians tended to come from areas with poor health, high levels of poverty—and bad record-keeping.

The true secret to extreme longevity seems to be to “move where birth certificates are rare, teach your kids pension fraud and start lying”,

Japanese community is at another level.