Excerpt from General Doolittle's Report on the Japanese Raid, delivered to the War Department on April 18,1942.
"the Japanese were apparently entirely unprepared for our arrival".
The anti-aircraft defense was active but inaccurate. All anti-aircraft bursts were black and apparently small guns of about 37 or 40 m.m. size. It is presumed that the high speed and low altitude at which we were flying made it impossible for them to train their larger caliber guns on us if such existed. Several of the airplanes were struck by anti-aircraft fragments but none of them was damaged to an extent that impaired their utility of impeded their progress. Although it was to be presumed that machine gun fire from the ground was active, none of the crew members interviewed to date saw any such action nor was there evidence of machine gun fires in the bottom of any of the airplanes. A few barrage balloons were seen. One cluster of five or six was observed just north of the Northernmost part of Tokyo Bay and what appeared to be another cluster was observed near the Bay to the Southeast. These barrage balloons were flying at about 3000 feet and were not in sufficient numbers to impede our bombing. Japanese anti-aircraft fire was so inaccurate that when shooting at one of our airplanes in the vicinity of the barrage balloons they actually shot down some of their own balloons.
We anticipated that some difficulty might be experienced due to our targets being camouflaged. Little or no effective camouflage was observed in the Tokyo area.
We can only infer that as the result of an unwarranted feeling of security and an over-all shortage of aircraft and pilots, home defense had been made secondary to efficient operation in other theaters. It is felt that the indicated low morale of the Japanese pilots around Tokyo compared to the efficiency and aggressiveness of pilots encountered on the active front was the result of a knowledge on their part of the inadequacy of their equipment and their own personal inefficiency.
In spite of the fact that at least one radio message was gotten off prior to our take-off by the Japanese patrol boat that was later sunk -- that we passed a Japanese light cruiser (thought by one of the pilots to be a tanker) about miles East of Tokyo -- a Japanese patrol plane or bomber headed directly for our task force about 600 miles from Tokyo (this plane turned around and followed one of our airplanes so we know we were observed by it) and innumerable Japanese patrol and fishing boats from some 300 miles off-shore until crossing the Japanese Coast, the Japanese were apparently entirely unprepared for our arrival. Inasmuch as messages must have been received at some message center, we can only presume poor dissemination of information or the complete failure of their communication system.