Bombing of Tokyo

The bombing of Tokyo (東京大空襲, Tōkyō daikūshū) was a series of air raids on Japan by the United States Army Air Forces (USAAF), primarily launched during the closing campaigns of the Pacific Theatre of World War II in 1944–1945, prior to the atomic bombings of Hiroshima and Nagasaki.

The strikes conducted by the USAAF on the night of 9–10 March 1945, codenamed Operation Meetinghouse, constitute the single most destructive aerial bombing raid in human history. Sixteen square miles (41 km²; 10,000 acres) of central Tokyo was destroyed, leaving an estimated 100,000 civilians dead and over one million homeless.

The U.S. mounted the Doolittle Raid, a small-scale air raid on Tokyo by carrier-based long-range bombers, in April 1942. However, strategic bombing and urban area bombing of Japan only began at scale in 1944 after the long-range B-29 Superfortress bomber entered service. Superfortress were first deployed from China and thereafter from the Mariana Islands, after they were seized from Japanese forces in mid-1944. B-29 raids from the Marianas began on 17 November 1944 and lasted until 15 August 1945, the day of the Japanese surrender.

Over half of Tokyo's industry was spread out among residential and commercial neighborhoods; firebombing cut the city's industrial output in half. Some modern post-war analysts have called the raids a war crime due to the mass targeting of civilian infrastructure and ensuing large-scale loss of civilian life.

The first American air attack on Tokyo was the Doolittle Raid on 18 April 1942. Sixteen B-25 Mitchells modified for carrier operations were launched from USS Hornet, after which they bombed Yokohama and Tokyo and flew on to airfields in China. The raid was largely symbolic, carried out in retaliation for the Japanese attack on Pearl Harbor five months prior. The raid caused minimal damage to Japan's warfighting capability, but was a significant propaganda victory for the United States. The bombers took off at longer range than planned when the Hornet's task force encountered a Japanese picket boat, resulting in all of the attacking aircraft either crashing or being ditched by their crews short of their designated landing sites. One bomber landed in the neutral Soviet Union and its crew was interned, but then smuggled over the border into Iran on 11 May 1943. Two crews were captured by the Japanese in occupied China. Three captured crewmen were later executed by Japanese troops.

The key development that enabled the USAAF to bomb Japan at scale was the B-29 Superfortress strategic bomber, which had an operational range of 3,250 nautical miles (3,740 mi; 6,020 km) and was capable of attacking at high altitude above 30,000 feet (9,100 m), where Japanese air defenses struggled to reach them. Almost 90% of the bombs dropped on the Japanese home islands were delivered by the B-29. The capture of islands sufficiently close to Japan (particularly Saipan and Tinian, seized in June 1944) enabled B-29s based at airfields there to bomb the home islands with increasing regularity.

Prior to the capture of the Marianas, long-range bombing raids were carried out by the Twentieth Air Force operating out of mainland China in Operation Matterhorn under XX Bomber Command. However, while these raids were able to strike parts of southern Japan, they were out of range of Tokyo. It was also logistically difficult for the Allies to maintain a large bomber force in China via circuitous supply routes from India. The strategic situation improved when flight operations from the Northern Mariana Islands commenced in November 1944, but high-altitude bombing attacks using general-purpose bombs were observed to be ineffective by USAAF leaders due to high winds—later discovered to be the jet stream—which carried the bombs off target. Between May and September 1943, bombing trials were conducted on the Japanese Village set-piece target, located at the Dugway Proving Grounds in Utah. These trials demonstrated the effectiveness of incendiary bombs against wood-and-paper buildings common in Japan, and eventually resulted in Curtis LeMay ordering his bomber wings to change tactics and utilize these munitions against Japanese targets.

The first American raid utilizing incendiary munitions was carried out against Kobe on 4 February 1945. Tokyo was hit by incendiaries on 25 February 1945 when 174 B-29s flew a high altitude raid during daylight hours, destroying around 643 acres (260 ha) (2.6 km²) of the snow-covered city, using 453.7 tons of both incendiary and fragmentation bombs. Subsequently, LeMay ordered further B-29 raids on the capital, but at a much lower altitude of 5,000 to 9,000 ft (1,500 to 2,700 m) and at night, judging that Japan's air defenses were weakest in this altitude range, and that Japanese fighter defenses were ineffective at night. LeMay ordered all defensive guns but the tail gun removed from the B-29s, allowing the aircraft to be lighter, use less fuel and carry more ordnance.