Incendiary Bombing of Japan

From: The Army Air Forces in World War II, volume Five, June 1944 to August 1945. (1983)

Urban Area Attacks

On March 6, 1945, General LeMay said “This outfit has been getting a lot of publicity without having really accomplished a hell of a lot in bombing results.” This referred to the early B-29 bombing of Japan, which was high-level bombing and generally not overly accurate or damaging. The bombing was done in the daytime and was referred to as “precision” bombing, even though it wasn't all that “precision.”

Thought was given to the construction of Japanese buildings, which were largely paper and wood structures. “Tests conducted at Eglin Field and Dugway Proving Ground on model urban areas of typical Japanese construction seemed to add scientific confirmation to a judgment based on common sense. ...Japanese cities would prove much more vulnerable to fire bombing than had comparable German cities, because of more inflammable residential construction and greater congestion.”

The decision was made to use low-level incendiary bombing, bringing the planes in at 5,000 or 6,000 feet. “Some of LeMay's flak experts thought it would be suicidal” to use those altitudes. but LeMay “considered Japanese flak much less dangerous than the German. Japanese gun-laying radar was not efficient, and searchlights, though plentiful and annoying, were no substitute for electronic control.”

It was also decide that the runs would be made at night. “In operational respects, there was much in favor of the night missions. Clouds over Japan tended to thin out at night, and at the proposed altitudes winds were not too formidable. On the return flight, planes would meet an early dawn somewhere about Iwo Jima and it would be easier to land or to ditch damaged planes. Most important of all, the low altitude would allow a very heavy bomb load.”

When B-29's flew at high altitudes, they often encountered strong winds, which made the “precision” bombing much less effective. The higher the planes went, the more fuel they had to carry and the more wear and tear there was on the planes. By flying lower, there was less wind, less wear on the planes, and less fuel needed. The less fuel, the more bombs.

The Great Fire Raids

The first major raid was set for the night of March 9/10, 1945. 334 B-29's were scheduled for the raid. It was such a large group that it took two and three-quarters hours just to get the entire group airborne.

They flew in three wings at altitudes from 4,900 to 9,200 feet. Once some fires started, the B-29s fanned out to start more fires. “The area attacked was a rectangle measuring approximately four by three miles. It was densely populated, with an average of 103,000 inhabitants to the square mile.”

The area contained home industries and feeder plants of wood-bamboo-plaster construction. The fire that resulted was so severe that tail gunners could see the glow for 150 miles.

The raid lasted for three hours. Fighter defense was almost non-existent. 42 B-29's were damaged by flak. 14 were shot down with 5 of the crews were rescued.

15.8 square miles of the city had been burned out, which included 18% of the industrial area and 63% of the commercial area. The fire chief of the area later said that, within thirty minutes, the fire situation was out of control. 93 fire engines were destroyed, and 125 firemen were killed. 167,171 buildings were destroyed, which was about 1/4th of those in Tokyo. 1,008,005 people were made homeless. 83,793 died, and 40,918 were wounded. There were so many dead that it took 25 days to remove all the bodies from the ruins.

Radio Tokyo called it “slaughter bombing.” The area destroyed was far more than of any other city for a man-made cause. By comparison, the great fire of London destroyed 436 acres. The 1871 Chicago fire destroyed 2,114 acres and 17,450 buildings. The San Francisco earthquake, a natural event, destroyed 11,188 buildings. The fire-bombing of Tokyo destroyed around fifteen times as many buildings as the earthquake.

“The effect on Japanese morale was profound.”

On March 11th, less than 29 hours after the Tokyo bombing, 313 B-29's took off for Nagoya, which was Japan's third largest city. The bombing was not as efficient, though, and only 2.05 square miles of the city were destroyed. 18 industrial targets were destroyed, but the aircraft plants weren't. What helped keep the damage down was the fact that “Nagoya had an adequate water supply, well-space firebreaks, and an efficient fire department which adopted excellent tactics for the occasion.”

20 planes were damaged, and one plane had to ditch.

The third mission was designated for Osaka. Osaka was Japan's 2nd largest city. It had harbor facilities and excellent rail and highway connections. It made about 10% of Japan's wartime total of ships, much of her electrical equipment, and a third of her machinery and machine tools. The city also had an army arsenal that accounted for 10% of the army's ordinance requirements.

The planes attacked on March 13th. The 274 planes had to use radar bombing since there were so many clouds. The raid lasted about three hours and destroyed 8.1 square miles in the heart of the city. 199 major factories were destroyed. 3,988 people died, 678 were missing, and 8,463 were injured. 134,744 houses were destroyed. 13 B-29's were damaged, and t wo were lost.

Kobe was attacked on the 16th. Kobe had a lot of heavy industry installations. There was more resistance by Japanese fighters than there had been so far, though. The raid lasted a little over two hours. 2.9 square miles of the city were destroyed. 65,951 homes were destroyed, and 141,468 people were made homeless. There were 2,669 dead or missing and 11,189 injured. About one fifth of the city's area had been destroyed.

On March 19th, the B-29s again attacked Nagoya. Three square miles were destroyed this time, and the arsenal, freight yards, and other targets were damaged.

For the first four raids, the B-29s had destroyed 32 square miles of Japanese cities. The effect on U.S. A.A.F. morale was very positive.

The Joint Target Group decided where to go from there. Thirty-three urban areas were to be included in the new plan of attack, divided into various phases. Phase 1 was to include Tokyo, Kawasaki, Nagoya, Osaka and Yawata. Phase 2 was to include Tokyo, Yokohama, Kawasaki, Kobe, Amagaski, Osaka and Nagoya. The other group was to be Tokyo, Nagoya, Osaka, Amagasaki and Yawata.

In addition, more specific targets were designated, including Osaka Army Arsenal, Kure Naval Arsenal, Hiro Arsenal, Kokura Arsenal, Sasebo Naval Arsenal, and the Koriyama chemical works.

Examples of some of the raids that were done just before the official program got started included April 17, Tokyo again. This time 11.4 square miles of the industrial section were burned out. April 15th saw Tokyo hit again, with 6 sq. miles destroyed. Kawasaki had 3.6 sq.miles destroyed, and Yokohama had 1.5 square miles destroyed. 117,130 buildings in Tokyo and Yokohama were destroyed, and 31,603 in Kawasaki.

Nagoya was the target for the first raid in the new series. It took place on May 14th. Some 471 B-29's dropped 2,515 tons of incendiaries, starting some 131 separate fires before counting became impossible due to smoke coverage. 3.15 square miles of the city were destroyed, and an important Mitsubishi plant was destroyed. Ten B-29's were lost, and 18 Japanese planes were shot down.

Nagoya was attacked again on May 16th. The dock and industrial areas were targeted. 457 planes dropped 3,609 tons of bombs.3.82 more square miles of the city were destroyed. Nagoya was dropped from the area-attack bombing schedule, but there were six more attacks of a precision nature that were later made.

A total of 113,460 buildings were destroyed in Nagoya as a result of the attacks, with 3,866 people kiled and 471,701 made homeless.

On May 23rd and 25th, more raids were carried out on Tokyo. 520 planes destoyed 5.3 square miles of the city on May 23rd. The May 25th attack destroyed 16.8 square miles of the city. The six incendiary missions on Tokyo had burned out 56.3 square miles, which was over half of the entire city area. Tokyo was then removed from the incendiary bombing list of targets.

Next up was Yokohama, an important shipbuilding and automotive center. 517 B-29s were involved, but there was a much stronger Japanese fighter effort, with around 150 Zekes involved. P-51 Mustang pilots destroyed 26 of them, and possibly as many as 23 more. The raid destroyed 6.9 square miles of the city, which was about a third of the city's area. This brought the total area destroyed in all attacks on the city to 8.9 square miles.

A raid on Osaka resulted in 3.15 square miles destroyed. A June 5th attack on Kobe destroyed 4.35 square miles and destroyed 51,399 buildings. Osaka was again hit two days later, with 2.21 square miles destroyed and over 1000 industrial buildings destroyed.

On June 15th two cities were attacked, Osaka and Amagasaki. Over 500 B-29's were involved. 1.9 square miles of Osaka was destroyed, and .59 square miles of Amagasaki. Although fewer square miles were destroyed, the damage to industrial structures was actually severe.

“Inhabitants of the great cities, already disturbed by news of military defeats and by B-29 precision attacks, lost confidence in their leaders' ability to defend them from attack or to care for the victims.”

This is one thing that interests me quite a bit, and that's the number of sources that talk about the lowering of morale among the civilian population of Japan. The sources seem to think that it's an important thing, but I have my doubts. The average Japanese person had no input about who made up the government or what the government did. The secret police made sure that no one was able to speak out in public against the government. It wasn't like any significant portion of the Japanese civilian populace was going to go on some kind of massive anti-war strike.

From everything I have read, it seems to me that the Japanese civilians were going to be willing to do whatever the government ordered them to do as far as participating actively in the war if the home islands were invaded. Granted, if they had refused they probably would have been killed, as happened to civilians on Okinawa who didn't want to surrender to U.S. troops. The end result would have been the same; no matter what the average person thought about the war, he or she would have “died for the Emperor” anyhow, and their morale wasn't really important to anyone in the government.

After the Tokyo firebombing raid, Joseph C. Grew, who had been the ambassador to Japan, tried to talk Truman into toning down the “unconditional surrender” concept, but Truman's military advisers convinced him not to.

The end result of the 17 raids: 6,960 B-29's were used (obviously, some more than once). They carried 41,592 tons of bombs. 136 B-29's were lost, which was an average of 1.9 percent of the sorties, which was considered acceptable.

Industrial Targets

”The experiment with night precision attacks as short-lived.”

On April 7th, bombers attacked the Mitsubishi engine works in Nagoya. This ended up destroying around 90% of the plant's facilities.

On April 24th bombers attacked the Tachikawa plant of the Hitachi Aircraft Corporation in Yamato. The plant was completely wrecked and there was no attempt to rebuild it.

On May 11th, planes attacked the Kawanishi Aircraft Company in Konan. Damage to the plant was so severe that the company removed the remaining machine tools.

The report details a variety of other, similar attacks.

Incendiary Attacks on the Smaller Cities

Once the bigger cities were burned out, then the military turned to smaller cities to attack. The preferred targets were based on:

1. congestion and inflammability

2. incidence of war industry

3. incidence of transportation facilities

4. size and population

5. adaptability to radar bombing.

The list consisted of 25 cities ranging from Fukuoka to Hachioji in population.

These missions would attack two or more cities at the same time, rather than one city at a time as on the first set of missions. Usually four cities were attacked at the same time. This was done sixteen times, average twice a week.

Yawata was one of the cities attacked, with 1.22 square miles destroyed, which composed 21% of its urban area.

“The Japanese air forces never devised an effective defense against night attacks; they had no first-rate night fighter and no efficietn means of vectoring to the interceptors they sent up.

A psychological warfare-type of thing was added when leaflets would be dropped on Japanese cities. The leaflets would have a list of a dozen cities or so, and would say that they were subject to an impending attack. The military would then destroy some of the cities in the next few days. This tended to cause even more people to move out of the various cities, which would have an effect of reducing the number of workers available for the war-related factories.

“In general the incendiary attacks on the smaller cities were highly successful.” The report says that the burned-out areas ranged from 43% of the city to 99.5 percent of Toyama. Production of war goods in bombed cities fell to about a third of pre-bombing amounts.


Mining of harbors and other areas was also undertaken. Japan started the war with about 6 million tons of shipping, and added 823,000 tons from areas they conquered. Their own ship-building program was not well developed, and they had no convoy system set up. Sinkings exceeded replacements even in 1941.

For most of the war, the submarine was the main destroyer of merchant shipping.

In the Philippine campaign, the Japanese lost 1,300,000 tons of shipping.

25% of the emergency rice stocks of Japan were destroyed in the fire blitz.

The Japanese tried to do minesweeping, but it wasn't very effective. The effect of all of this mining and bombing can be seen in the Kobe-Osaka area. They had shipped 320,000 tons in March, 1945, but by July this had dropped to 44,000 tons. The Japanese lost 478,000 tons of shipping in July alone, and their entire merchant marine had been reduced to 1,500,000 tons by the middle of August.

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