302nd bombardment Group (H) 1 Jun 1942 - 10 Apr 1944
331st Bombardment Group (VH) 7 Jul 1944 - 15 Apr 1946
1st Lt. Ronald V. Kramer, 21 Jun 1942
Capt. Earl D. Carlson, 4 Jul 1942
Capt. Walter Cross, 23 Jul 1942
Capt. Benjamin M. Sheldon, 23 Sep 1942
Capt. Horace S. Carswell, 23 Jan 1943
Capt. Frank L. Smith, 20 May 1943
Capt. Zane L. Abbott, 23 Aug 1943
unknown, 5 Mar - 10 Apr 1943
Maj. Thomas E. Whitson, by Aug 1944
Maj. Joesph S. Grimm, by Oct 1944
Capt. Louis C. Carr, by Jun 1945
Maj. Andrew F. Gordon, 18 Jul 1945 - unkn.
(Air Offensive Campaign Japan 17 April 1942 to 2 September 1945) The United States strategic bombing of Japan took place between 1942 and 1945. In the last seven months of the campaign, a change to firebombing resulted in great destruction of 67 Japanese cities, as many as 500,000 Japanese deaths and some 5 million more made homeless. Emperor Hirohito's viewing of the destroyed areas of Tokyo in March 1945 is said to have been the beginning of his personal involvement in the peace process, culminating in Japan's surrender five months later.
The first U.S. raid on the Japanese main island was the Doolittle Raid of 18 April 1942, when sixteen B-25 Mitchells were launched from the USS Hornet (CV-8) to attack targets including Yokohama and Tokyo and then fly on to airfields in China. The raids were military pinpricks but a significant propaganda victory. Because they were launched prematurely, none of the aircraft had enough fuel to reach their designated landing sites, and so either crashed or ditched (except for one aircraft, which landed in the Soviet Union, where the crew was interned). Two crews were captured by the Japanese.
The key development for the bombing of Japan was the B-29 Superfortress, which had an operational range of 1,500 miles (2,400 km); almost 90% of the bombs (147,000 tons) dropped on the home islands of Japan were delivered by this bomber. The first raid by B-29s on Japan was on 15 June 1944, from China. The B-29s took off from Chengdu, over 1,500 miles away. This raid was also not particularly effective: only forty-seven of the sixty-eight bombers hit the target area; four aborted with mechanical problems, four crashed, six jettisoned their bombs because of mechanical difficulties, and others bombed secondary targets or targets of opportunity. Only one B–29 was lost to enemy aircraft. The first raid from east of Japan was on 24 November 1944, when 88 aircraft bombed Tokyo. The bombs were dropped from around 30,000 feet (10,000 m) and it is estimated that only around 10% hit their targets.
Raids of Japan from mainland China, called Operation Matterhorn, were carried out by the Twentieth Air Force under XX Bomber Command. Initially the commanding officer of the Twentieth Air Force was Hap Arnold, and later Curtis LeMay. Bombing from Japan from China was never a satisfactory arrangement because not only were the Chinese airbases difficult to supply—materiel being sent by air from India over "the Hump"—but the B-29s operating from them could only reach Japan if they traded some of their bomb load for extra fuel in tanks in the bomb-bays. When Admiral Chester Nimitz's island-hopping campaign captured Pacific islands close enough to Japan to be within the B-29's range, the Twentieth Air Force was assigned to XXI Bomber Command, which organized a much more effective bombing campaign of the Japanese home islands. Based in the Marianas (Guam and Tinian in particular), the B-29s were able to carry their full bomb loads and were supplied by cargo ships and tankers.
Conventional bombs from B-29s destroyed over 40% of the urban area in Japan's six greatest industrial cities
Unlike all other forces in theater, the USAAF Bomber Commands did not report to the commanders of the theaters but directly to the Joint Chiefs of Staff. In July 1945, they were placed under the U.S. Strategic Air Forces in the Pacific, which was commanded by General Carl Spaatz.
As in Europe, the United States Army Air Forces (USAAF) tried daylight precision bombing. However, it proved to be impossible due to the weather around Japan, "during the best month for bombing in Japan, visual bombing was possible for [just] seven days. The worst had only one good day." Further, bombs dropped from a great height were tossed about by high winds.
General LeMay, commander of XXI Bomber Command, instead switched to mass firebombing night attacks from altitudes of around 7,000 feet (2,100 m) on the major conurbations. "He looked up the size of the large Japanese cities in the World Almanac and picked his targets accordingly." Priority targets were Tokyo, Nagoya, Osaka, and Kobe. Despite limited early success, particularly against Nagoya, LeMay was determined to use such bombing tactics against the vulnerable Japanese cities. Attacks on strategic targets also continued in lower-level daylight raids.
The first successful firebombing raid was on Kobe on 3 February 1945, and following its relative success the USAAF continued the tactic. Nearly half of the principal factories of the city were damaged, and production was reduced by more than half at one of the port's two shipyards.
Much of the armor and defensive weaponry of the bombers was removed to allow increased bomb loads; Japanese air defense in terms of night-fighters and anti-aircraft guns was so feeble it was hardly a risk. The first raid of this type on Tokyo was on the night of 23–24 February when 174 B-29s destroyed around one square mile (3 km²) of the city. Following on that success, as Operation Meetinghouse, 334 B-29s raided on the night of 9–10 March, dropping around 1,700 tons of bombs. Around 16 square miles (41 km²) of the city was destroyed and over 100,000 people are estimated to have died in the fire storm. The destruction and damage was at its worst in the city sections east of the Imperial Palace. It was the most destructive conventional raid, and the deadliest single bombing raid of any kind in terms of lives lost, in all of military aviation history. The city was made primarily of wood and paper, and Japanese firefighting methods were not up to the challenge. The fires burned out of control, boiling canal water and causing entire blocks of buildings to spontaneously combust from the heat. The effects of the Tokyo firebombing proved the fears expressed by Admiral Yamamoto in 1939: "Japanese cities, being made of wood and paper, would burn very easily. The Army talks big, but if war came and there were large-scale air raids, there's no telling what would happen."
In the following two weeks, there were almost 1,600 further sorties against the four cities, destroying 31 square miles (80 km²) in total at a cost of 22 aircraft. By June, over forty percent of the urban area of Japan's largest six cities (Tokyo, Nagoya, Kobe, Osaka, Yokohama, and Kawasaki) was devastated. LeMay's fleet of nearly 600 bombers destroyed tens of smaller cities and manufacturing centres in the following weeks and months.
Leaflets were dropped over cities before they were bombed, warning the inhabitants and urging them to escape the city. Though many, even within the Air Force, viewed this as a form of psychological warfare, a significant element in the decision to produce and drop them was the desire to assuage American anxieties about the extent of the destruction created by this new war tactic. Warning leaflets were also dropped on cities not in fact targeted, to create uncertainty and absenteeism.