April 18, 1942. 72 years ago today, sixteen U.S. Army Air Forces B-25B Mitchell medium bombers were launched without fighter escort from the USS Hornet deep in the Western Pacific Ocean, each with a crew of five men. The plan called for them to bomb military targets in Japan, and to continue westward to land in China—landing a medium bomber on Hornet was impossible. Fifteen of the aircraft reached China, and the other one landed in the Soviet Union. All but three of the crew survived, but all the aircraft were lost. Eight crewmen were captured by the Japanese Army in China; three of these were executed. The B-25 that landed in the Soviet Union was confiscated and its crew interned for more than a year. Fourteen crews, except for one crewman, returned either to the United States or to American forces.
After the raid, the Japanese Imperial Army conducted a massive sweep through the eastern coastal provinces of China, in an operation now known as the Zhejiang-Jiangxi Campaign, searching for the surviving American airmen and applying retribution on the Chinese who aided them, in an effort to prevent this part of China from being used again for an attack on Japan. An estimated 250,000 Chinese civilians were killed by the Japanese during this operation.
The raid caused negligible material damage to Japan, only hitting non-military targets or missing completely but it succeeded in its goal of raising American morale and casting doubt in Japan on the ability of its military leaders to defend their home islands. It also caused Japan to withdraw its powerful aircraft carrier force from the Indian Ocean to defend their home islands, and the raid contributed to Admiral Isoroku Yamamoto's decision to attack Midway Island in the Central Pacific—an attack that turned into a decisive strategic defeat of the Imperial Japanese Navy by the U.S. Navy in the Battle of Midway. Doolittle, who initially believed that loss of all his aircraft would lead to his being court-martialled, received the Medal of Honor and was promoted two steps to Brigadier General.