Hiroshima

The city of Hiroshima is located on the broad, flat delta of the Ota River,
which has 7 channel outlets dividing the city into six islands which
project into Hiroshima Bay. The city is almost entirely flat and only
slightly above sea level; to the northwest and northeast of the city some
hills rise to 700 feet. A single hill in the eastern part of the city
proper about 1/2 mile long and 221 feet in height interrupted to some
extent the spreading of the blast damage; otherwise the city was fully
exposed to the bomb. Of a city area of over 26 square miles, only 7
square miles were completely built-up. There was no marked separation of
commercial, industrial, and residential zones. 75% of the population was
concentrated in the densely built-up area in the center of the city.

Hiroshima was a city of considerable military importance. It contained the
2nd Army Headquarters, which commanded the defense of all of southern
Japan. The city was a communications center, a storage point, and an
assembly area for troops. To quote a Japanese report, "Probably more than
a thousand times since the beginning of the war did the Hiroshima citizens
see off with cries of 'Banzai' the troops leaving from the harbor."

The center of the city contained a number of reinforced concrete buildings
as well as lighter structures. Outside the center, the area was congested
by a dense collection of small wooden workshops set among Japanese houses;
a few larger industrial plants lay near the outskirts of the city. The
houses were of wooden construction with tile roofs. Many of the industrial
buildings also were of wood frame construction. The city as a whole was
highly susceptible to fire damage.

Some of the reinforced concrete buildings were of a far stronger
construction than is required by normal standards in America, because of
the earthquake danger in Japan. This exceptionally strong construction
undoubtedly accounted for the fact that the framework of some of the
buildings which were fairly close to the center of damage in the city did
not collapse.

The population of Hiroshima had reached a peak of over 380,000 earlier in
the war but prior to the atomic bombing the population had steadily
decreased because of a systematic evacuation ordered by the Japanese
government. At the time of the attack the population was approximately
255,000. This figure is based on the registered population, used by the
Japanese in computing ration quantities, and the estimates of additional
workers and troops who were brought into the city may not be highly
accurate. Hiroshima thus had approximately the same number of people as
the city of Providence, R.I., or Dallas, Tex.


Nagasaki

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.