“Doolittle´s after-effects”
On 18 April 1942, in the First Bombing of Japan, LtCol (later Gen/Medal of Honor) James H. Doolittle's force of 16 North American B-25 "Mitchell" twin-engine Army bombers of the 17th Bomb Group took off from Captain (later Admiral) Marc A. Mitscher's carrier USS HORNET (CV-8) and struck targets in Tokyo, Yokohama, Osaka, Nagoya and Kobe. Four days later, at 1525, on 21 April, the brand-new flying boat tender AKITSUSHIMA was running official builder trials off Wada-misaki, Kobe when a large airplane approached the vessel. The aircraft was identified as an enemy B-25 bomber! Immediately, AKITSUSHIMA opened fire with her brand-new AA-machine guns. Nearby, at the same time, Settsu Shosen´s passenger ship TENNYO MARU (495grt) was running her regular passenger service between Kobe and Awaji Island ports. At 1528, TENNYO MARU sent an emergency call that she was under machine gun fire thought to come from a large aircraft seen flying in the vicinity. Finally, it became clear that AKITSUSHIMA had mistaken a Japanese transport plane for a B-25 bomber and that shell splinters from her AA-fire had rained down on nearby TENNYO MARU! The Doolittle Raid had, in deed, left a deep impact on Japanese psychology!
Source:
http://www.combinedfleet.com/Strange.htm