would be at least two alternates.

E. Selection of targets to produce the greatest military effect on the
Japanese people and thereby most effectively shorten the war.

F. The morale effect upon the enemy.

These led in turn to the following:

A. Since the atomic bomb was expected to produce its greatest amount of
damage by primary blast effect, and next greatest by fires, the targets
should contain a large percentage of closely-built frame buildings and
other construction that would be most susceptible to damage by blast and
fire.

B. The maximum blast effect of the bomb was calculated to extend over an
area of approximately 1 mile in radius; therefore the selected targets
should contain a densely built-up area of at least this size.

C. The selected targets should have a high military strategic value.

D. The first target should be relatively untouched by previous bombing, in
order that the effect of a single atomic bomb could be determined.

The weather records showed that for five years there had never been two
successive good visual bombing days over Tokyo, indicating what might be
expected over other targets in the home islands. The 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