Nagasaki lies at the head of a long bay which forms the best natural
harbor on the southern Japanese home island of Kyushu. The main
commercial and residential area of the city lies on a small plain near
the end of the bay. Two rivers divided by a mountain spur form the two
main valleys in which the city lies. This mountain spur and the
irregular lay-out of the city tremendously reduced the area of
destruction, so that at first glance Nagasaki appeared to have been
less devastated than Hiroshima.
The heavily build-up area of the city is confined by the terrain to
less than 4 square miles out of a total of about 35 square miles in the
city as a whole.
The city of Nagasaki had been one of the largest sea ports in southern
Japan and was of great war-time importance because of its many and
varied industries, including the production of ordnance, ships,
military equipment, and other war materials. The narrow long strip
attacked was of particular importance because of its industries.
In contrast to many modern aspects of Nagasaki, the residences almost
without exception were of flimsy, typical Japanese construction,
consisting of wood or wood-frame buildings, with wood walls with or
without plaster, and tile roofs. Many of the smaller industries and
business establishments were also housed in wooden buildings or
flimsily built masonry buildings. Nagasaki had been permitted to grow
for many years without conforming to any definite city zoning plan and
therefore residences were constructed adjacent to factory buildings and
to each other almost as close as it was possible to build them
throughout the entire industrial valley.