Bombing of Tokyo (10 March 1945)

On the night of 9/10 March 1945 the United States Army Air Forces (USAAF) conducted a devastating firebombing raid on Tokyo, the Japanese capital city. This attack was code-named Operation Meetinghouse by the USAAF and is known as the Great Tokyo Air Raid in Japan. During the raid, bombs dropped from 279 Boeing B-29 Superfortress heavy bombers burned out much of eastern Tokyo. More than 88,000 and possibly over 100,000 Japanese, mostly civilians, were killed and one million left homeless, making it the single most destructive air attack of World War II. The Japanese air and civil defenses proved inadequate, and only 14 American aircraft and 96 airmen were lost.

The attack on Tokyo was an intensification of the air raids on Japan which had commenced in June 1944. Prior to this operation, the USAAF had focused on a precision bombing campaign against Japanese industrial facilities. These attacks were generally unsuccessful, which contributed to the decision to shift to firebombing. The operation during the early hours of 10 March was the first major firebombing raid against a Japanese city, and the USAAF units employed significantly different tactics than those used in precision raids including bombing by night. The extensive destruction caused by the raid led these tactics to become standard for the USAAF's B-29s until the end of the war.

Background


The American Doolittle Raid on 18 April 1942 was the first air attack on Tokyo, but inflicted little damage on the city. In June 1944 the USAAF's XX Bomber Command began a campaign against Japan using B-29 Superfortress bombers flying from airfields in China. Tokyo was beyond the range of Superfortresses operating from China, and was not attacked. This changed in October 1944, when the B-29s of the XXI Bomber Command began moving into airfields in the Mariana Islands. These islands were close enough to Japan for the B-29s to conduct a sustained bombing campaign against Tokyo and most other Japanese cities. The first Superfortress flight over Tokyo took place on 1 November, when a reconnaissance aircraft photographed industrial facilities in city.

The overall plan for the strategic bombing campaign against Japan specified that it would commence with precision bombing raids against key industrial facilities, and later include firebombing attacks on cities. The first target directive issued to the XXI Bomber Command by its parent unit, the Twentieth Air Force, on 11 November 1944 specified that the main target was Japanese aircraft and aviation engine factories. These targets were to be attacked by precision bombing. Japanese cities were specified as the secondary target, with area bombing being authorized for use against them. The directive also indicated that firebombing raids were likely to be ordered against cities to test the effectiveness of this tactic. The Twentieth Air Force had an unusual command structure, as it was personally headed by General Henry H. Arnold, the commanding officer of the USAAF.

B-29 raids on Tokyo commenced on 24 November. The first raid targeted an aircraft engine factory on the city's outskirts, and caused little damage. XXI Bomber Command's subsequent raids on Tokyo and other cities mainly used precision bombing tactics and high explosive bombs, and were largely unsuccessful due to adverse weather conditions and a range of mechanical problems which affected the B-29s. These failures led to the head of the Command being relieved in January 1945. Major General Curtis LeMay, the commander of XX Bomber Command, replaced him. Arnold and the Twentieth Air Force's headquarters regarded the campaign against Japan up to that time as unsuccessful, and LeMay understood that he would also be relieved if he failed to deliver results. LeMay believed that changing the emphasis from precision bombing to area bombing was the most promising option to turn the XXI Bomber Command's performance around.

Early incendiary raids
USAAF planners began assessing the feasibility of a firebombing campaign against Japanese cities in 1943. Japan's main industrial facilities were vulnerable to such attacks as they were concentrated in several large cities, and a high proportion of production took place in homes and small factories in urban areas. The planners estimated that incendiary bomb attacks on Japan's six largest cities could cause physical damage to almost 40 percent of industrial facilities and result in the loss of 7.6 million man-months of labor. It was also estimated that these attacks would kill over 500,000 people, render about 7.75 million homeless and force almost 3.5 million to be evacuated. The plans for the strategic bombing offensive against Japan developed in 1943 specified that it would transition from a focus on the precision bombing of industrial targets to area bombing from around halfway in the campaign, which was forecast to be in March 1945. The British and American bombing campaign against Germany also included frequent area bombing of cities, which resulted in the deaths of hundreds of thousands of civilians and massive firestorms in cities such as Hamburg and Dresden. The Japanese conducted area bombing attacks on Chinese cities throughout the war. In preparation for firebombing raids, the USAAF tested the effectiveness of incendiary bombs on the adjoining German and Japanese-style domestic set-piece building complexes at the Dugway Proving Ground during 1943. These trials demonstrated that M69 incendiaries were particularly effective at starting uncontrollable fires. These weapons were dropped from B-29s in clusters, and used napalm as their incendiary filler. After the bomb struck the ground, a fuse ignited a charge which first sprayed napalm from the weapon, and then ignited it.

Several raids were conducted to test the effectiveness of firebombing against Japanese cities. A small incendiary attack was made against Tokyo on the night of 29/30 November 1944, but caused little damage. Incendiaries were also used as part of several other raids. On 18 December, 84 XX Bomber Command B-29s conducted an incendiary raid on the Chinese city of Hankou which caused extensive damage. That day, the Twentieth Air Force directed XXI Bomber Command to dispatch 100 B-29s on a firebombing raid against Nagoya. An initial attack took place on 22 December, directed at an aircraft factory, involving 78 bombers using precision bombing tactics. Few of the incendiaries landed in the target area. On 3 January, 97 Superfortresses were dispatched on a firebombing raid against Nagoya. This attack started some fires, which were soon brought under control by Japanese firefighters. The success in countering the raid led the Japanese to become over-confident about their ability to protect cities against incendiary raids. The next firebombing raid was directed against Kobe on 4 February, and bombs dropped from 69 B-29s started fires which destroyed or damaged 1,039 buildings.

On 19 February the Twentieth Air Force issued a new targeting directive for XXI Bomber Command. While the Japanese aviation industry remained the primary target, the directive placed a stronger emphasis on firebombing raids against Japanese cities. The directive also called for a large-scale trial incendiary raid as soon as possible. This attack was made against Tokyo on 25 February. A total of 231 B-29s were dispatched, of which 172 arrived over the city; this was XXI Bomber Command's largest raid up to that time. The attack was conducted in daylight, with the bombers flying in formation at high altitudes. It caused extensive damage, with almost 28,000 buildings being destroyed. This was the most destructive raid to have been conducted against Japan, and LeMay and the Twentieth Air Force judged that it demonstrated that large-scale firebombing raids were an effective tactic.

The failure of a precision bombing attack on an aircraft factory in Tokyo on 4 March marked the end of the period in which XXI Bomber Command primarily conducted such raids. Civilian casualties during these operations had been relatively low; for instance, all the raids against Tokyo prior to 10 March caused 1,292 deaths in the city.

Preparations to attack Tokyo
In early March LeMay judged that further precision bombing of Japanese industrial targets was unlikely to be successful due to the prevailing weather conditions over the country. There were on average only seven days of clear skies each month, and an intense jet stream made it difficult to aim bombs from high altitudes. Due to these constraints, LeMay decided to focus XXI Bomber Command's attacks on Japanese cities. On 5 March XXI Bomber Command's personnel were advised that no further major attacks would be scheduled until 9 March. During this period LeMay's staff finalized plans for the attack on Tokyo. At a meeting on 7 March, LeMay agreed to conduct an intense series of raids against Honshu between 9 and 22 March as part of the preparations for the invasion of Okinawa on 1 April.

LeMay decided to adopt radically different tactics for this campaign. Analysis by XXI Bomber Command staff of the 25 February raid concluded that the incendiary bombs had been dropped from too high an altitude, and attacking at lower levels would both improve accuracy and enable the B-29s to carry more bombs. However, this would also expose them to the Japanese air defenses. LeMay judged that poor Japanese fire control tactics meant that the additional risk was moderate. As weather conditions over Japan tended to be more favourable at night and the LORAN systems the B-29s used to navigate were more effective after dusk, it was also decided to conduct the attack at night. This led to a decision to direct the aircraft to attack individually rather than in formations as it was not possible for the B-29s to keep station at night. Flying individually would also lead to reductions in fuel consumption as the pilots would not need to constantly adjust their engines to remain in formation. These fuel savings allowed the Superfortresses to carry twice their usual bomb load. USAAF intelligence had determined that the Japanese had only two night fighter units, and these were believed to pose little threat. As a result, LeMay decided to remove all of the B-29s' guns other than those at the rear of the aircraft in order to reduce the weight of the aircraft and further boost the weight of bombs they could carry. On 7 March, some of the B-29 crews flew training missions in which they practiced using radar to navigate to and attack a target from a low altitude. The airmen were not told the purpose of this training.

The officers who commanded XXI Bomber Command's three flying wings agreed with the new tactics, but there were fears that they could result in heavy casualties. These concerns were shared by some of LeMay's staff. XXI Bomber Command's intelligence officers predicted that 70 percent of the bombers could be destroyed. LeMay consulted Arnold's chief of staff Brigadier General Lauris Norstad about these changes, but did not formally seek approval to adopt them. He later justified this action on the grounds that he had wanted to protect Arnold from blame had the attack been a failure. LeMay notified the Twentieth Air Force headquarters of his intended tactics on 8 March, a day he knew Arnold and Norstad would be absent. There is no evidence that LeMay expected that the Twentieth Air Force would object to firebombing civilian areas, but he may have been concerned that it would judge that his new tactics were too risky.

Japanese defenses
The Japanese military anticipated that the USAAF would make major night attacks on the Tokyo region. After several small night raids were conducted on the region during December 1944 and January 1945, the Imperial Japanese Army Air Force's 10th Air Division, which was responsible for intercepting attacks on the Kantō region, placed a greater emphasis on training its pilots to operate at night. One of the division's flying regiments (the 53rd Air Regiment) was also converted to a permanent night fighter unit. On the night of 3/4 March, the Japanese military intercepted American radio signals which indicated that the XXI Bomber Command was conducting a major night flying exercise. This was interpreted to mean that the force was preparing to start large-scale night raids on Japan. However, the Japanese did not expect the Americans to change to low altitude bombing tactics.

The military forces assigned to protect Tokyo were insufficient to stop a major raid. The Eastern District Army's Kanto Air Defense Sector was responsible for the air defense of the Tokyo Region, and was accorded the highest priority for aircraft and antiaircraft guns. The 1st Antiaircraft Division controlled the antiaircraft guns stationed in the central region of Honshu, including Tokyo. It was made up of eight regiments with a total of 780 antiaircraft guns, as well as a regiment equipped with searchlights. American military intelligence estimated that 331 heavy and 307 light antiaircraft guns were allocated to Tokyo's defenses at the time of the raid. Due to shortages of radar and other fire control equipment, Japanese antiaircraft gunners found it difficult to target aircraft operating at night. As of March 1945, most of the 10th Air Division's 210 combat aircraft were day fighters, with the 53rd Air Regiment operating 25 or 26 night fighters. The regiment was experiencing difficulties converting to the night fighter role, which included an overly intensive training program that left the regiment's pilots exhausted. A network of picket boats, radar stations and lookout posts was responsible for detecting incoming raids. However, the radar stations had a short range and fire control equipment for the antiaircraft batteries was unsophisticated.

Tokyo's civil defenses were also lacking. The city's fire department comprised around 8,000 firemen spread between 287 fire stations, but they had little modern firefighting equipment. The firefighting tactics used by the fire department were ineffective against incendiary bombs. Civilians had been organized into more than 140,000 neighbourhood firefighting associations with a nominal strength of 2.75 million people, but these were also ill-equipped. The basic equipment issued to the firefighting associations was incapable of extinguishing fires started by M69s. Few air raid shelters had been constructed, though most households dug crude foxholes to shelter in near their homes. Firebreaks had been created across the city in an attempt to stop the spread of fire; over 200,000 houses were destroyed as part of this effort. However, the rubble from the houses was often not cleared, and provided a source of fuel. The Japanese Government also encouraged children and civilians with non-essential jobs to evacuate Tokyo, and 1.7 million had departed by March 1945. However, many other civilians had moved into Tokyo from impoverished rural areas over the same period.

Departure
On 8 March LeMay issued orders for a major firebombing attack on Tokyo the next night. The raid was to target a rectangular area in north-eastern Tokyo designated Zone I by the USAAF which measured approximately 4 mi by 3 mi. This area was divided by the Sumida River, and included most of Asakusa, Honjo and Fukagawa Wards. It was mainly residential and, with a population of around 1.1 million, was one of the most densely populated urban areas in the world. Zone I contained few militarily significant industrial facilities, though there were a large number of small factories which supplied Japan's war industries. The area was highly vulnerable to firebombing, as most buildings were constructed from wood and bamboo and were closely spaced. The orders for the raid issued to the B-29 crews stated that the main purpose of the attack was to destroy the many small factories located within the target area, but also noted that it was intended to cause civilian casualties as a means of disrupting production at major industrial facilities. Each of XXI Bomber Command's three wings was allocated a different altitude to bomb from, in bands between 5000 ft and 7000 ft. These altitudes were calculated to be too high for the light Japanese antiaircraft guns to reach, and below the effective altitude of the heavy antiaircraft guns.

LeMay was unable to lead the raid in person as he had been prohibited from placing himself in a situation where he could be captured after being briefed on the development of atomic bombs. Instead, the attack was led by the 314th Bombardment Wing's commanding officer, Brigadier General Thomas S. Power. The new tactics which were to be used in the operation were not well received by many airmen, who believed that it was safer to bomb from high altitudes and preferred to retain their defensive guns.

In preparation for the attack, XXI Bomber Command's maintenance staff worked intensively over a 36 hour period to ready as many aircraft as possible. This effort proved successful, and 83 percent of the B-29s were available for action compared to the average serviceability rate of 60 percent. Other ground crew loaded the aircraft with bombs and fuel. A total of 346 B-29s were readied. The 73rd Bombardment Wing contributed 169 B-29s and the 313rd Bombardment Wing 121; both units were based on Saipan. At the time of the raid the 314th Bombardment Wing was arriving at Guam in the Marianas, and able to provide only 56 B-29s. The B-29s in the squadrons which were scheduled to arrive over Tokyo first were armed with M47 bombs; these weapons used napalm and were capable of starting fires which required mechanized firefighting equipment to control. The bombers in the other units were loaded with clusters of M69s. The 73rd and 313rd Bomb Wings' Superfortresses were each loaded with seven tons of bombs. As the 314th Bombardment Wing's B-29s would have to fly a greater distance, they each carried five tons of bombs.

The attack force began departing its bases at 5:35 pm local time on 9 March. It took two and three quarter hours for all of the 325 B-29s which were dispatched to take off. Turbulence was encountered on the flight to Japan, but the weather over Tokyo was good. There was little cloud cover, and visibility from the bombers was 10 mi. Conditions on the ground were cold and windy, with the city experiencing gusts of between 45 and 67 miles per hour blowing from the south-east.

Over Tokyo
The attack on Tokyo commenced at 12:08 am local time on 10 March. Pathfinder bombers simultaneously approached the target area at right angles to each other. Their M47 bombs rapidly started fires in an X shape, which was used to direct the attacks for the remainder of the force. Each of XXI Bomber Command's wings and their subordinate groups had been briefed to attack different areas within the X shape to ensure that the raid caused widespread damage. As the fires expanded, the American bombers spread out to attack unaffected parts of the target area. Power's B-29 circled Tokyo for 90 minutes, with a team of cartographers who were assigned to him mapping the spread of the fires.

The raid lasted for approximately two hours and forty minutes. Visibility over Tokyo decreased over the course of the raid due to the extensive smoke over the city. This led some American aircraft to bomb parts of Tokyo well outside the target area. The heat from the fires also resulted in the final waves of aircraft experiencing heavy turbulence. Some American airmen also needed to use oxygen masks when the odor of burning flesh entered their aircraft. A total of 279 B-29s attacked Tokyo, dropping 1,665 tons of bombs. Another 19 Superfortresses which were unable to reach Tokyo struck targets of opportunity or targets of last resort. These aircraft turned back early due to mechanical problems or pilots deciding to abort the fight due to anxiety about their prospects of surviving the mission.

Tokyo's defenders were expecting an attack, but did not detect the American force until it arrived over the city. The air defense units in the Kanto Plain area had been placed on alert, but the night fighter units were instructed to not sortie any aircraft until an incoming raid was detected. While picket boats spotted the attack force, poor radio reception meant that most of their reports were not received. Due to disorganisation in the defense commands, little action was taken on the scattered reports which came in from the boats. At around midnight on 9 March a small number of B-29s were detected near Katsuura, but were thought to be conducting routine reconnaissance flights. Subsequent sightings of B-29s flying at low levels were not taken seriously, and the Japanese radar stations focused on searching for American aircraft operating at their usual high altitudes. The first alarm that a raid was in progress was issued at 12:15 am, just after the B-29s began dropping bombs on Tokyo. The 10th Air Division sortied all of its available night interceptors, and the 1st Antiaircraft Division's searchlight and antiaircraft units went into action.

As expected by LeMay, the defense of Tokyo was not effective. Many American units encountered considerable antiaircraft fire, but it was generally either aimed at altitudes above or below the bombers and reduced in intensity over time as many gun positions were overrun by fires. Nevertheless, the Japanese gunners shot down 12 B-29s. A further 42 were damaged, of which two had to be written off. The Japanese fighters were ineffective; their pilots received no guidance from radar stations and the efforts of the antiaircraft gunners and fighter units were not coordinated. No B-29s were shot down by fighters, and the American airmen reporting only 76 sightings of Japanese fighters and 40 attacks by them over the course of the raid. Several Japanese pilots were killed when their aircraft ran out of fuel. Five of the downed B-29s managed to ditch in the sea, and their crews were rescued by United States Navy submarines. American casualties were 96 airmen killed or missing, and 6 wounded or injured.

The surviving B-29s arrived back at their bases in the Mariana Islands between 6:10 and 11:27 am local time on 10 March. Many of the bombers were streaked with ashes from the fires their crews had caused.

On the ground
Widespread fires rapidly developed across north-eastern Tokyo. Within 30 minutes of the start of the raid the situation was beyond the fire department's control. An hour into the raid the fire department abandoned its efforts to stop the conflagration. Instead, the firemen focused on guiding people to safety and rescuing those trapped in burning buildings. Over 125 firemen and 500 civil guards who had been assigned to help them were killed, and 96 fire engines destroyed.

Driven by the strong wind, the large numbers of small fires started by the American incendiaries rapidly merged into major blazes. These formed firestorms which quickly advanced in a north-westerly direction and destroyed or damaged almost all the buildings in their path. The only buildings which survived the fire were constructed of stone. By an hour after the start of the attack most of eastern Tokyo had either been destroyed or was being affected by fires.

Civilians who stayed at their homes or attempted to fight the fire had virtually no chance of survival. Historian Richard B. Frank has written that "the key to survival was to grasp quickly that the situation was hopeless and flee". Soon after the start of the raid news broadcasts began advising civilians to evacuate as quickly as possible, but not all did so immediately. The foxholes which had been dug near most homes offered no protection against the firestorm, and civilians who sheltered in them were burnt to death or died from suffocation.

Thousands of the evacuating civilians were killed. Families often sought to remain with their local neighbourhood associations, but it was easy to become separated in the conditions. Few families managed to stay together throughout the night. Escape frequently proved impossible, as smoke reduced visibility to just a few feet and roads were rapidly cut by the fires. The majority of those killed in the raid died while trying to evacuate. In many cases entire families were killed. One of the single most deadly incidents occurred when the full bomb load of a B-29 landed in a crowd of civilians crossing the Kokotoi Bridge over the Sumida River causing hundreds of people to be burnt to death.

Few places in the targeted area provided safety. Many of those who attempted to evacuate to the large parks which had been created as refuges against fires following the 1923 Great Kantō earthquake were killed when the conflagration moved across these open spaces. Similarly, thousands of people who gathered in the grounds of the Sensō-ji temple in Asakusa died. Others sheltered in solid buildings, such as schools or theatres, and in canals. These were not proof against the firestorm, with smoke inhalation and heat killing large numbers of people in schools. Many of the people who attempted to shelter in canals were killed by smoke or when the passing firestorm sucked oxygen out of the area. However, these bodies of water provided safety to thousands of others. The fire finally burnt itself out during mid-morning on 10 March, and came to a stop when it reached large open areas or the Nakagawa Canal. Thousands of people injured in the raid died over the following days.

Casualties
Estimates of the number of people killed in the bombing of Tokyo on 10 March differ. After the raid, 79,466 bodies were recovered and recorded. Many other bodies were not recovered, however, and the city's director of health estimated that 83,600 people were killed and another 40,918 wounded. The Tokyo fire department put the casualties at 97,000 killed and 125,000 wounded, and the Tokyo Metropolitan Police Department believed that 124,711 people had been killed or wounded. After the war, the United States Strategic Bombing Survey estimated that 87,793 people had been killed and 40,918 injured. The Survey also stated that the majority of the casualties were women, children and elderly people. Frank wrote in 1999 that historians generally believe that there were between 90,000 and 100,000 fatalities, but some argue that the actual number was much higher. For instance, Edwin P. Hoyt stated in 1987 that 200,000 people had been killed and in 2009 Mark Selden wrote that the number of deaths may have been several times the estimate of 100,000 used by the Japanese and United States Governments. The large scale population movements out of and into Tokyo in the period before the raid, deaths of entire communities and destruction of records mean that it is not possible to know exactly how many died.

Most of the bodies which were recovered were buried in mass graves during the days after the raid without being identified. Many bodies of people who had died while attempting to shelter in rivers were swept into the sea and never recovered. Attempts to collect bodies ceased 25 days after the raid.

The raid also caused widespread destruction. Police records show that 267,171 buildings were destroyed, and 1,008,005 survivors were rendered homeless. This represents a quarter of all buildings in Tokyo at the time. Most buildings in the Asakusa, Fukagawa, Honjo, Joto and Shitaya wards were destroyed, and seven other districts of the city experienced the loss of around half their buildings. Parts of another 14 wards suffered damage. Overall, 15.8 sqmi of Tokyo was burnt out. The number of people killed and area destroyed was the largest of any single air raid of World War II, including the atomic bombings of Hiroshima and Nagasaki.

After the raid, civilians across Tokyo offered assistance to the refugees. Firemen, police officers and soldiers also tried to rescue survivors trapped under collapsed buildings. Many refugees who had previously lived in slums were accommodated in prosperous parts of the city. Some of these refugees resented the differences in living conditions, prompting riots and looting. Refugee centers were also established in parks and other open areas. Over a million people left the city in the following weeks, with more than 90 percent being accommodated in nearby prefectures. Due to the extent of the damage and the exodus from Tokyo, no attempt was made to restore services to large sections of the city.

Reactions
LeMay and Arnold considered the operation to have been a significant success on the basis of reports made by the airmen involved and the extensive damage shown in photographs taken by reconnaissance aircraft on 10 March. Arnold sent LeMay a congratulatory message which stated that "this mission shows your crews have the guts for anything". The aircrew who conducted the attack were also pleased with its results. The raid was followed by similar attacks against Nagoya on the night of 11/12 March, Osaka in the early hours of 14 March, Kobe on 17/18 March, and Nagoya again on 18/19 March. An unsuccessful night precision raid was also conducted against an aircraft engine factory in Nagoya on 23/24 March. The firebombing attacks ended only because XXI Bomber Command's stocks of incendiaries were exhausted. The attacks on Tokyo, Nagoya, Osaka and Kobe during March burnt out over 31 sqmi of the cities.

The Japanese Government initially attempted to suppress news of the 10 March raid on Tokyo. However, rumours of the devastation rapidly spread across the country. When the Japanese Government's official broadcaster Radio Tokyo eventually reported the attack it was labelled "slaughter bombing". The casualties and damage caused by the raid and absenteeism by workers in Tokyo considerably disrupted the Japanese war economy.

Few steps were taken to improve Tokyo's defenses after the raid. The majority of the 10th Air Division's senior officers were sacked or reassigned as punishments for the unit's failure on 10 March. However, only 20 aircraft were sent to Tokyo to reinforce the 10th Air Division, and these were transferred elsewhere two weeks later when no further attacks were made against the capital. From April, the Japanese ceased attempting to intercept Allied air raids in order to preserve aircraft to contest the expected invasion of Japan. The 1st Antiaircraft Division remained active until the end of the war in August 1945. The Japanese military never developed effective defenses against air raids conducted at night, with the night fighter force remaining ineffective and many cities not being protected by antiaircraft guns.

Between April and mid-May XXI Bomber Command mainly focused on attacking airfields in southern Japan in support of the invasion of Okinawa. From 11 May until the end of the war the B-29s conducted day precision bombing attacks when weather conditions were favourable, and night firebombing raids against cities at all other times. Further incendiary attacks were conducted against Tokyo, with the final taking place on the night of 25/26 May. By this time, 50.8 percent of the city had been destroyed and more than 4 million people left homeless. Further heavy bomber raids against Tokyo were judged to not be worthwhile, and it was removed from XXI Bomber Command's target list. By the end of the war, 75 percent of the sorties conducted by XXI Bomber Command had been part of firebombing operations. Few concerns were raised in the United States during the war about the morality of the 10 March attack on Tokyo or the other firebombing raids directed against Japanese cities.

Remembrance
Following the war the bodies which had been buried in mass graves were exhumed and cremated. The ashes were interred at a charnel house in Yokoamicho Park which had originally been established to hold the remains of 58,000 victims of the 1923 earthquake. A Buddhist service has been conducted to mark the anniversary of the raid on 10 March each year since 1951. A number of small neighbourhood memorials were established across the affected area in the years after the raid.

Few other memorials were erected to commemorate the attack in the decades after the war. Efforts began in the 1970s to construct an official Tokyo Peace Museum to mark the raid, but the Tokyo Metropolitan Assembly cancelled the project in 1999. Instead, the Dwelling of Remembrance memorial to civilians killed in the raid was built in Yokoamicho Park. This memorial was dedicated in March 2001. The citizens who had been most active in campaigning for the Tokyo Peace Museum established the privately-funded Center of the Tokyo Raids and War Damage, which opened in 2002. As of 2015, this center was the main repository of information in Japan about the firebombing raids.

In 2007 a group of survivors of the 10 March raid and bereaved families launched a lawsuit seeking compensation and an apology for the Japanese Government's actions regarding the attack. As part of the case, it was argued that the raid had been a war crime and the Japanese Government had acted wrongly by agreeing to elements of the 1951 Treaty of San Francisco which waived the right to seek compensation for such actions from the US Government. The plaintiffs also claimed that the Japanese Government had violated the post-war constitution by compensating the military victims of the raid and their families, but not civilians. The Japanese Government argued that it did not have an obligation to compensate the victims of air raids. In 2009 the Tokyo District Court found in favor of the Government.

Historiography
Many historians have stated that the 10 March raid on Tokyo was a military success for the United States, and marked the start of the most effective period of air raids on Japan. For instance, the USAAF official history judged that the attack fully met LeMay's objectives, and it and the subsequent firebombing raids shortened the war. More recently, Tami Davis Biddle noted in The Cambridge History of the Second World War that "The Tokyo raid marked a dramatic turn in the American air campaign in the Far East; following on the heels of many months of frustration, it loosed the full weight of American industrial might on the faltering Japanese".

Historians have also discussed the significance of the raid in the USAAF's transition from an emphasis on precision bombing to area bombing. Conrad C. Crane has observed that "the resort to fire raids marked another stage in the escalation towards total war and represented the culmination of trends begun in the air war against Germany. Like the attack on Dresden, the bombing of Tokyo on 10 March 1945 is often used as a key example by historians and commentators who criticise the ethics and practices of the Allied strategic bombing campaigns.

Emperor Hirohito toured the destroyed portions of Tokyo shortly after the bombing. The experience was the beginning of his personal involvement in the peace process, culminating in Japan's surrender five months later.