At a bank counter in Tokyo, 55-year-old Mr. Yamada is handling mortgage inheritance procedures for his 25-year-old son. This special loan agreement has a 100-year term—he and his son will be repaying this three-bedroom apartment together.


The 'Grandchild-Generation Mortgage' launched by Sumitomo Mitsui Banking Corporation in 2013 extended the maximum repayment age from 80 to 85. When the borrower passes away, their children can inherit the loan and the property. On the surface, it's a financial innovation, but it hides the dual crises of a rapidly aging population and soaring housing prices.

A real estate agent in Yokohama showed me some data: the average price of a new condominium in the Tokyo metropolitan area is now 13 times the average annual income. For a 30-year-old salaried worker buying a home with a standard salary, the monthly mortgage payment would account for 60% of their income. "Many people choose a 100-year mortgage not because they want to, but because they have to."

This mortgage model is like a slow-burning social experiment. A couple in Osaka told me they pay 120,000 yen (approximately 5,600 RMB) a month and expect to pay off the principal only when they are 75. "Our son says he will sell the house eventually, because he doesn't want his own children to be burdened by debt."

But the risks are starting to emerge. A 2022 report by Japan's Financial Services Agency showed that the mortgage default rate for households headed by someone over 65 doubled within five years. When interest rates rise from 0.5% to 1.5%, these intergenerational debt chains become strained.

The real irony is that while this type of mortgage helps stabilize housing prices, it also makes it harder for the younger generation to accumulate wealth. It's like running on a treadmill to pay off debt—you run your whole life, only to find yourself in the same place.