The Tokyo Metropolitan Government is working to reduce the areas where old wooden houses are concentrated to zero in the 2040s in preparation for a major earthquake that could strike the capital.

As of 2020, Tokyo had some 8,600 hectares of such areas that are expected to suffer particularly severe damage in the event of a large quake. In the major quake that shook Tokyo and surrounding areas a century ago, some 92,000 people were killed in the fire that broke out in such areas.

When central Tokyo was rebuilt after the 1923 quake, disaster-afflicted people and reconstruction workers built houses in surrounding areas, which are said to be the origin of the current areas with many old wooden houses.