Is it a high risk to purchase land on a slope or near a river, or to purchase a building on such land?

Yes, if we analyze the recent examples of natural disasters in Japan, we can say that the risk is high.

Due to natural disasters such as record-breaking heavy rains, land and roads on slopes often collapse, and land and roads near rivers are often submerged due to river flooding.

If you are considering purchasing a property in such a location, you should not forget that there are major risks involved.