Every year, a series of fires had swept through Tokyo since the Edo period. When combined with certain natural conditions such as high winds, these fires were capable of destroying between 500 and 1,000 habitations at a time. A particularly large conflagration could raze more than 10,000 dwellings. The fire-prevention legislation enacted to deal with these contingencies was based on the application of traditional fire countermeasures, such as the construction of thoroughfares and firebreaks, and on fireproofing of wooden structures.