[mikekchar]

I think that is the main reason. But also, people buy houses at different times of life in Japan. Often it's people nearing retirement, buying the "dream house". They want exactly what they want. It's a bit of a vicious circle, but people don't/can't do "starter homes" because you can't sell them.

Another common practice is to inherit your parent's or grandparent's house, knock it down and build a new one. So the same family will live in the same location for many generations, but they will rebuild the house in order to adapt to changing needs. I think this reflects the rapid rise in wealth in Japanese society. Before WWII, Japan was quite a poor country. From WWII onwards, Japan went from absolute poverty (where everything was flattened by the war) to the second largest economy on the planet (now, edged out by China for that honour). So every 20-30 years represented a major upgrade in housing.

I'm finding that in my area in the last 10 years used houses are getting slightly more popular. Certainly for me, when I eventually stop jetting back and forth between the UK and Japan I will buy a used house. A 20 year old house is still rated for a level 7 earthquake and I think they are perfectly good. I would say that at least 30% of my neighbours are over 60, so housing is going to be extremely easy to acquire (though still not a good investment).