During World War II the strategic bombing of targets without direct military value became a common policy. As capital of Japan, Tokyo was an obvious target as part of an assault on the "basic economic and social fabric of the country".
The first raid on Tokyo was the Doolittle Raid of April 18, 1942 when sixteen B-25 Mitchells were launched from the USS Hornet to attack targets including Yokohama and Tokyo and then fly on to airfields in China. Launched prematurely, the raids were military pin-pricks but a significant propaganda victory. None of the attacking aircraft reached the designated airfields, either crashing or ditching. Two crews were captured by the Japanese.
As the war moved closer to the Japanese mainland the AAF was able to execute larger raids. The key development was of the B-29, with a operational range of 1500 miles almost 90% of the bombs dropped on the home islands of Japan were delivered by this type of bomber (147,000 tons). The B-29 flew missions from India and China in early 1944 and later from the Marianas Islands (October 1944) and Tinian. The first raid by B-29s on Japan was on June 15 and the first raid from the east was on November 24, 1944 when 88 aircraft bombed Tokyo. The bombs were dropped from around 30,000 feet and it is estimated that only around 10% hit designated targets.
The scale of operations was stepped up following the arrival of Curtis LeMay to command the 21st Bomber Command on the Marianas Islands in January, 1945. B-29 raids were switched to night attacks from altitudes of around 7,000 feet on the major conurbations of Tokyo, Nagoya, Osaka, and Kobe. Despite limited early success with incendiary attacks LeMay was determined to use such bombs against the vulnerable Japanese cities. Attacks on strategic targets also continued in lower level daylight raids.
Aftermath of the firebombing
The fire bomb raids were not the only raids on Tokyo, there were more regular raids using conventional high explosives. With the capture of Okinawa the Eighth Air Force was to be transferred there. Monthly tonnage dropped on Japan had increased from 13,800 tons in March to 42,700 tons in July, and was planned to have continued to increase to around 115,000 tons per month.
Tokyo was not considered as a target for a nuclear attack, although Tokyo Bay was apparently examined as a target for a non-lethal demonstration.