The Atomic Bombings of Hiroshima and Nagasaki | Page 7

worst
month of the year for visual bombing was believed to be June, after
which the weather should improve slightly during July and August and
then become worse again during September. Since good bombing
conditions would occur rarely, the most intense plans and preparations
were necessary in order to secure accurate weather forecasts and to
arrange for full utilization of whatever good weather might occur. It
was also very desirable to start the raids before September.

DESCRIPTION OF THE CITIES BEFORE THE BOMBINGS
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