Japan is a bit of an outlier because of earthquake regulations.

There is a history of substantially updating building regulations every time a new record is set for largest earthquake in the modern era; and so if you are buying historical, you are buying a less safe property that could kill you.

The last major earthquake updates to the code were in 2000, so there isn’t a lot of historical housing stock without this confounding factor.

Seems like this should be a net cost adder. Yet even new builds are quite affordable.