It was not at first apparent to even trained observers visiting the two
Japanese cities which of the two bombs had been the most effective.

In some respects, Hiroshima looked worse than Nagasaki. The fire damage in
Hiroshima was much more complete; the center of the city was hit and
everything but the reinforced concrete buildings had virtually disappeared.
A desert of clear-swept, charred remains, with only a few strong building
frames left standing was a terrifying sight.

At Nagasaki there were no buildings just underneath the center of
explosion. The damage to the Mitsubishi Arms Works and the Torpedo Works
was spectacular, but not overwhelming. There was something left to see,
and the main contours of some of the buildings were still normal.

An observer could stand in the center of Hiroshima and get a view of the
most of the city; the hills prevented a similar overall view in Nagasaki.
Hiroshima impressed itself on one's mind as a vast expanse of desolation;
but nothing as vivid was left in one's memory of Nagasaki.

When the observers began to note details, however, striking differences
appeared. Trees were down in both cities, but the large trees which fell
in Hiroshima were uprooted, while those in Nagasaki were actually snapped
off. A few reinforced concrete buildings were smashed at the center in
Hiroshima, but in Nagasaki equally heavy damage could be found 2,300 feet
from X. In the study of objects which gave definite clues to the blast
pressure, such as squashed tin cans, dished metal plates, bent or snapped
poles and like, it was soon evident that the Nagasaki bomb had been much
more effective than the Hiroshima bomb. In the description of damage which
follows, it will be noted that the radius for the amount of damage was
greater in Nagasaki than Hiroshima.