United States Strategic Bombing Survey: Summary Report (Pacific War)

As usual, this will just point out some highlights of the report.

The survey was established on Nov. 3, 1944 by the Secretary of War. The actual report is dated July 1, 1946.

The Japanese failed to “...appreciate the full scope and complexity of the requirements for continuing control of the air.”

(My comments, not part of the report, of course. The Japanese didn't have a system to keep training high-quality pilots. Although they started the war with a better fighter than the U.S., they didn't keep their technological developments moving at the same level of the U.S., and fell behind in technology. They also didn't anticipate how much loss of air control would cost them, especially in ships sunk and U.S. planes bombing Japan itself.)

The Japanese air production program was inadequate at the start of the war, and couldn't keep pace with U.S. production.

“None of the responsible Japanese leaders believed that within any forseeable period of time Japan could invade the United States...”. The Japanese leaders also felt that their shipping would be inadequate for any really ambitious program against the U.S..

(What this means, of course, is that the Japanese, at least some of them, knew they would not be able to attack the U.S. directly. This meant that they would not be able to stop or even slow down significantly U.S. military production, unless they could stop the flow of raw materials in to the U.S., and they never really developed their submarine force to that effort.)

Japan took over Burma at the cost of 102 planes and 7,000 soldiers killed.

In relation to Japanese attempts to resupply their troops on Guadalcanal, “General Miyazaki testified that only 20 percent of the supplies dispatched from Rabaul to Guadalcanal ever reached there.” Of the Japanese forces there, around 10,000 were killed, around 10,000 starved to death, and around 10,000 were evacuated in February, 1943.

The report says that the Japanese Navy lost “operational freedom and striking power” due to its “limited carrier-based air strength.”

In the first year of the war, around 10% of Japanese merchant shipping was sunk by U.S. subs, and another 4% was destroyed by U.S. planes. (This only got worse as the war went on.)

During the war, the Japanese produced 65,300 planes. They were making 642 per month during the first nine months of the war, and got up to 2,572 per month in Sept. of 1944.

Their plane losses started at around 500 planes per month in the early part of the war. They increased to over 2,000 per month in the latter part of 1944. What I found particularly interesting was, of these losses, only 40% were due to combat. The other 60% were due to losses during training, ferrying and other noncombat causes.

At the end of the war, the Japanese still had 5,000 tactical planes, plus 5,400 kamikaze planes.

(From those statistics, it looks to me like the Japanese were still making more planes than they were losing. If they lost 2,000 per month, but still could make around 2500 per month, then that was a net gain of 500. Of course, this doesn't take into consideration that, during the latter part of the war, there was a major shortage of aviation fuel, and the pilots that existed were poorly trained. A gain of 500 planes per month did not mean necessarily a gain of 500 usable planes per month, in other words.)

The U.S. started the war producing around 200 planes per month (300 per month less than Japan.) This went to some 11,000 planes per month as of August 1945, which means that the U.S. was out-producing Japan by around 9000 planes per month by the war's end.

During the war, the U.S. lost around 27,000 planes, about 32% of which were combat losses, a rate only 8% lower than the Japanese rate. Over 60% of the losses were due to antiaircraft fire.

By the end of the war, Japanese pilots were getting around 100 hours of flight training, and U.S. pilots around 600 hours of flight training.

The report also criticizes the Japanese military (in relation to aircraft), saying they did not have adequate maintenance, logistic support or communications and control. It also says their air fields were not set up to handle large numbers of planes and couldn't control large formations of planes with any efficiency.

From Oct, 1944, to the end of the Okinawa campaign, the Japanese flew 2,550 kamikaze missions. Around 18.6% were effective in securing hits or near misses. No ships larger than an escort carrier were sunk. This kind of mission also, obviously, resulted in 100% casualty rates for the Japanese pilots (or, at least, for those who got to the fighting area; some turned back to do “engine problems.”)

(Still, they had maybe 14 to 15,000 planes that could have been used to meet any U.S. invasion of the home islands. There is no doubt that such an attack on U.S. forces would have resulted in very high casualties for the U.S. It might have been enough to sway public opinion enough that a negotiated end to the war would have been needed.)

The Japanese started the war with 10 carriers. Six were sunk in 1942. They made 17 new carriers and 5 escort carriers during the war. Seven more were lost in 1944. They also lost both of their super-battleships.

The Japanese started the war with 381 warships, and 816 combat ships (for a total of 1197 ships.) Of these, 549 were sunk, which amounts to about 45% of their ships.

In relation to merchant shipping, Japan started with 6 million tons of shipping over 500 tons gross weight, and added another 4.1 million tons during the war. 8.9 million tons was sunk. This produces an astonishing 88% of their merchant shipping being sunk (or out of action) during the war. Submarines did about 60% of this. This is also broken down into army supplies that were sunk. This amount to 17% sunk in 1943; 30% in 1944, and 50% in 1945.

Japanese army ground forces amount to around 5,000,000. 220,000 were deployed in Burma, of which 40,000 were killed (about 18%). 1,100,000 were deployed in China, of whom 103,000 were killed (about 9%). Most of those in Manchuria, Korea and the home islands did not actively participate in the war. The rest were directly involved in the island fighting. They numbered around 668,000. 316,000 of these were killed, for a total of 47% killed.

Japanese troops were often cut off from supplies and reinforcements. “On certain of the islands, Japanese actually ate Japanese.”

The Japanese economy had a potential of about 10% of the U.S. economy, according to the report. By the summer of 1944, the civilian population was underfed, and had higher rates of absenteeism.

“It is the opinion of the Survey that by August 1945, even with directair attack on her cities and industries, the over-all level of Japanese war production would have declined below the peak levels of 1944 by 40 to 50 percent solely as a result of the interdiction of overseas imports.”

The total tonnage of bombs dropped by the U.S. was 656,000. 24% were dropped on the home islands of Japan.

In relation to U.S. bombing of Japanese cities, some 40% of the built-up area of the cities was destroyed. About 30% of the urban population became homeless. The railroad system, though, was still quite functional.

“By 1944 the Japanese had almost eliminated home industry in their war economy.” (This is very important, in that the home industry argument was one used to justify the firebombings and the atomic bombings of Japanese cities.)

“The Japanese labor force had declined in efficiency due to malnutrition and fatigue, the destruction of much of the urban housing, and the difficulties of local transportation. Production hours lost through all causes including absenteeism, sickness, air-raid alerts and enforced idleness rose from 20 percent in 1944 to over 40 percent in July, 1945.”

Total civilian casualties in Japan were about 806,000, of which 330,000 were deaths.

Food shortages resulted in the average per capital caloric intake going from 2,000 calories at the time of Pearl Harbor (versus 3,400 calories for people in the U.S.), to 1,900 by 1944, and 1,680 by the summer of 1945.This also resulted in an increase in beriberi and tuberculosis.

In some kind of survey they found (and I'd like to know who conducted the survey, considering that the secret police really, really, really didn't like anyone bad-mouthing the war), around 10% of Japanese thought Japan would not win as of December, 1944. this increased to 19% by March, 1945, rose to 46% in June, and got to 68% at the time of surrender.

About one-fourth of the people in cities fled or were evacuated during the war.

In what, to me, is a very important statement, the report notes that “It is probable that most Japanese would have passively faced death in a continuation of the hopeless struggle, had the Emperor so ordered.” This strengthens the argument of those who said the use of the atomic bombs was justified because the U.S. casualties, and Japanese casualties, would have been really bad in any U.S. invasion of the home islands.

The population of Hiroshima had fallen from 340,000 down to 245,000 as a result of evacuations before the atomic bomb. Almost 3/4ths of the buildings in the city were destroyed or “rendered unusable” due to the atomic bomb. Around 70,000 were killed and 50,000 injured. The big plants on the edge of the city were undamaged and could have resumed normal production within a month of the bombing if the war had not ended.

Nagasaki's population fell from 285,000 to 230,000 before the atomic bomb was dropped.

“The Survey has estimated that the damage and casualties caused at Hiroshima by the one atomic bomb dropped from a single plane would have required 220 B-29s carrying 1,200 tons of incendiary bombs, 400 tons of high-explosive bombs, and 500 tons of anti-personnel fragmentation bombs, if conventional weapons, rather than an atomic bomb had been used. One hundred and twenty-five B-29s carrying 1,200 tons of bombs would have been required to approximate the damage and casualties at Nagasaki.”

(Which brings up a question. If the same destruction could have been caused by regular planes using regular bombs, why wasn't that done instead of using the atomic bombs? )

“...it is the Survey's opinion that certainly prior to 31 December 1945, and in all probability prior to 1 November, 1945, Japan would have surrendered even if the atomic bombs had not been dropped, even if Russia had not entered the war, and even if no invasion had been planned or contemplated.”

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