While directing, Roger Spottiswoode tried to be even-handed in the portrayal of the Japanese military leaders, and it was the Japanese co-director who would keep coming back and saying "You don't really understand; they were much more intransigent than that." Some of the top military men over there had a pretty good idea of the resources required for the bomb, and didn't believe anyone could sustain the attacks.
The Image Entertainment laserdisc of the film featured an audio commentary by director Roger Spottiswoode and creative consultant Matthew Asner that was not retained on either the Pioneer DVD released in 2000 or the Platinum Disc DVD released in 2005.
Spottiswoode commented to the pilot about what a shame it was that of the thousands of the magnificent machines built, that only the B-29 one was still flying. The pilot (a World War Two veteran) was not so nostalgic, and replied "This thing was designed and built for just one purpose; to kill thousands of people at a time. One is more than enough."
Some of the internal scenes aboard the B-29 were filmed in the only remaining example that is still capable of flight. That one belonged to the Confederate Air Force, which is now called the Commemorative Air Force due to political correctness.
Len Watt's final film.