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]]]]]]]]]]]] THE JAPANESE A-BOMB [[[[[[[[[[[[[[[[[[[[
[Kindly uploaded by Freeman 10602PANC] (9/13/1988)
Nuclear Weapons History: Japan's Wartime Bomb Projects Revealed
By Deborah Shapley
[This is an abridged and slightly edited version of the article
appearing in Science, 13 Jan 1978, pp. 152-157]
A little-publicized chapter in the history of atomic weapons
is the Japanese effort to develop an atomic bomb during World War
II. The effort centered around Japan's university physics
laboratories, and its chief figure was Yoshio Nishina, who was
Japan's leading scientist and a physicist of international
stature.
Much has been written about how the United States and Britain
during the war were concerned that the Germans, who had
discovered atomic fission in the 1930's, would develop the
world's first superbomb based on this principle. Indeed, the
German wartime atomic research effort was a major rationale for
the Manhattan Project in the United States.
But in the case of Japan it seems that no one in the U.S.
government took the possibility of a Japanese atomic bomb project
seriously.
Still more curious is the curtain of silence which the
Japanese themselves seem to have pulled over the subject, and
which they have kept tightly drawn since the war. Even the
Americans who interrogated Nishina concluded that Japan had had
no atomic bomb project.
Even today in Japan, when historians tell Japanese that there
was such a project, many Japanese react with disbelief. Japan's
postwar official policy, that she does not and never will seek to
be a nuclear-armed country, seems to have inhibited discussion of
the project. Japan's wartime atomic research, in Japan, has
become a social secret.
The effort is documented in two authoritative Japanese
histories. One is a history of science and technology in Japan
of which volume 13, published in 1970, deals with science and
technology during World War II. The second is a social history
of science, by Tetu Hirosige, published in 1973, that has an
entire chapter devoted to the wartime science mobilization,
including among other things, atomic research. Nishina died in
1951 and there is no known account by him of his wartime
activities. But there are other firsthand accounts, notably the
diary of Masa Takeuchi, a worker at Nishina's laboratory who was
assigned to the thermal diffusion project, and a memoir of
Bunsabe Arakatsu, a physicist from Kyoto.
These materials have been collected independently by Herbert
F. York, Jr., director of the Program in Science, Technology and
Public Affairs at the University of California at San Diego, and
Charles Weiner, professor of history of science at the
Massachusetts Institute of Technology (M.I.T.). Weiner is now
completing a full-scale historical study of the subject.
It is no surprise that physicists in Japan were tempted,
around 1940, to study the military applications of fission.
Throughout the 1930's, Japan had kept pace with the exciting
developments in physics -- with theory in Europe and experimental
techniques in the United States. Nishina spent several years in
Copenhagen in the laboratory of Niels Bohr.
The Japanese also became schooled in the techniques of the
cyclotron, through a small machine built at the Riken, Nishina's
laboratory in Tokyo, and by sending a much younger physicist,
Ryokichi Sagane, to Berkely to work under E.O. Lawrence.
Lawrence arranged for the contribution of a 200-ton magnet for a
second cyclotron at the Riken. The cyclotron was not finished
until 8 years later, shortly before the war's end.
While Japanese physics at the outset of the war was strong
enough to carry researchers naturally into the problem of the
fission weapon, it was "too brittle," to bring the project to a
successful conclusion. Nishina, Sagane, and some others were
clearly world class physicists; but Japanese physics included a
"comparatively large number of nonadvanced fields."
Scientists Suggest Project
The scientists themselves initiated atomic bomb research in
September 1940. Army sponsorship was arranged, and "fairly
large-scale research" began at the Riken "from December, 1940."
The years 1940 and 1941 were a period of intense military
interest in the possibilities of atomic weapons. In 1941, Prime
Minister and War Minister Hideki Tojo's order for investigation
of the possibilities for a fission weapon were passed on to the
Riken.
But in the first of what was to be a series of uncoordinated
orders to the scientists, the Navy also engaged the Riken's
services, and launched an inquiry into the feasibility of the
weapon in late 1942. This led to the "Physics Colloquium," a
galaxy of Japan's leading scientists who met for ten sessions
between December 1942 and March 1943, to investigate the
feasibility of Japan's achieving a weapon.
The Colloquium's conclusion, relayed to the Navy in March
1943, was that an atomic bomb would be impossible "even" for the
United States for the current war. Another account says that it
estimated Japan would need "ten years" to develop such a weapon.
So it seems that the scientists viewed the project as extremely
long term at best, or, as one of them would later write: "if not
for this war then in time for the next one."
On the other hand, the military viewed the bombs as something
to be pursued immediately, although it often did not back up this
commitment with resources. The planners of Pearl Harbor, it is
known, assumed that the war in the Pacific would be short,
brutal, and brilliant. They believed that America, then being
irrevocably drawn into hostilities in Europe, would retreat
quickly from fighting on a second front in the Pacific.
It is well established that another faction in the Japanese
government was restrained and realistic, and probably this
element took a wait-and-see attitude, and relegated the problem
to the scientists. But the zealots were still there. A new
book, Enola Gay*, quotes the physicist Tsunesabo Asada's
recollection that discussions of the subject right after Pearl
Harbor were characterized by a "mood of blind patriotism" and
"promises of generous funding."
Arakatsu, writing after the war, said he did atomic bomb
research to prevent young scientists from being sent to fight and
die. Takeuchi, in his diary, which was also compiled after Japan
had surrendered, says that he did the research only when ordered,
and that other Riken scientists were equally unenthusiastic.
However well these rationales suited the postwar climate of
opinion, there is evidence that the actual situation was
different. At several junctures when the scientists might well
have closed down the work altogether -- for they knew better than
anyone how great were the odds against success -- they kept the
work going.
September 1940 had been one such juncture; March 1943 was
another. Following the physics colloquium's negative report, the
Navy branch that had sponsored it lost interest in the atomic
bomb. But Nishina managed to keep the Riken atomic research
going. The Army, which had been funding the work since December
1940, became the sole sponsor of Riken atomic research.
But this was by no means the beginning of coordination among
the military. Just as the Naval Institute of Technology bowed
out of support of atomic research in March 1943, another Navy
branch, the Fleet Administration Center, was sponsoring another
group of researchers at Kyoto University, under Arakatsu, to work
toward an atomic bomb.
The Kyoto project began in 1942 and was enlarged with a grant
of 600,000 yen in 1943. Among other things, the money went to
construct a cyclotron at Kyoto university. But the military's
commitment to the work -- however strong in spirit -- was not
backed up with material aid.
Takeuchi's diary also indicates that atomic research at the
Riken was anything but coordinated. Takeuchi complains that
although he was told to consider the possibility of separating
uranium by electromagentic means, Miyamoto, who had developed
such a method, had gone to another university. So Takeuchi gave
up on electromagnetic separation because he couldn't have
Miyamoto around to help. Similarly, although Takeuchi found
gaseous thermal diffusion "the most promising" method, Eiichi
Takeda, who had done small-scale thermal diffusion work using a
glass column, was not assigned to the project. So, Takeuchi had
to start from scratch.
After much delay and red tape the apparatus was ready in a
separate building in early 1945. It took Takeuchi 18 months to
do this work, whereas physicists in the United States were able
to set up comparable or larger experiments in a matter of weeks.
In April 1945, as the gaseous thermal diffusion apparatus and
the cyclotron were finally working together in an experimental
mode, the building housing the apparatus -- but not the cyclotron
-- was ruined in the American bomber raids over Toko. The
wrecking of their experiment caused the scientists to give up on
their atomic research -- that is, until after Hiroshima.
After Hiroshima, the government seems to have become
interested yet again in having an atomic bomb. According to one
account, the morning after the bomb was dropped, Nishina was
summoned and asked first whether the bomb could have been atomic
and "whether Japan could have one in six months."
Nishina was flown over Hiroshima on 8 August. The pattern of
destruction and the presence of radiation convinced him the bomb
had been an atomic one. Arakatsu reached a similar conclusion
when he was flown over the city on 10 August.
After Hiroshima, the scientists at the Riken resumed their
atomic studies, but with a different goal, namely to learn about
the effects of the weapons at Hiroshima and Nagasaki. Philip
Morrison, now of M.I.T., who served on the Manhattan Project, and
arrived in Japan on the first day of the American occupation,
recalled what he found when he visited the Japanese scientists.
Nishina was "guarded and self contained ... impassive and
almost antagonistic," toward the arriving Americans. On the
other hand, many other Japanese physicists seemed to welcome the
Americans with "rueful pleasure." Morrison recalls that the
feelings of internationalism, of a bond among physicists, seemed
to reestablish itself between the Americans and Japanese -- with
the exception of Nishina. And as for whether Japan had been
developing an atomic weapon, he recalls, "they didn't talk about
it and we didn't ask about it much."
The Riken buildings and laboratories "looked frayed,
unrenovated, starved of attention." In places, work had just
stopped and people had gone away. "As we looked around we
concluded this could not have been the site of a Japanese
Manhattan Project."
It is not surprising that U.S. scientists visiting Japan who
knew firsthand the "panoply" of installations and people that was
the American Manhattan Project, concluded that the Japanese could
not have had a comparable project.
So it went in the fall of 1945. Visiting American scientists
were sympathetic to Japanese "colleagues" and tended to find no
evidence of a bomb project. The Japanese were silent to their
American military interrogators; thus the military, by and large,
also found no evidence of such a project.
The Joint Chiefs of Staff ordered on 30 October that all
research facilities and equipment "on atomic energy and related
subjects be seized." "No research ... on atomic energy shall be
permitted in Japan."
On 24 to 26 November 1945, on orders from General Groves'
office, which oversaw the Manhatttan Project, American military
teams proceeded to hack Japan's five cyclotrons, including the
two at Riken, to pieces. The remains were dumped into the sea.
In the furor which arose in the United States, scientists' and
citizens' groups protested to the Secretary of War. For the most
part they were told that the destruction order had been a
mistake. But this confession of error only whetted the appetites
of many of the scientists, who had now become embroiled in a
fight for future civilian control of atomic energy. The
destruction of the cyclotrons was used to show how insensitive
the military would be to the special needs of science and
scientists.
Admiral Nakamura "Talks"
But was the destruction completely mindless?
There is a U.S. Army document, dated before the order to
destroy the cyclotrons, in which a Rear Admiral Nakamura reports
in detail on atomic bomb research conducted during the war at
Kyoto University. Among other things, it says that the project
included the construction of a cyclotron.
So far there is no evidence that the report reached Groves'
office. But its existence suggests that some Americans learned
of the wartime atomic research and concluded that the cyclotrons
should be destroyed.
On 31 December when Lee DuBridge, director of the M.I.T.
Radiation Laboratory, wrote to the acting secretary of war on
behalf of the scientific community, suggesting that U.S.
scientists restore "at least Dr. Nishina's 60-inch [cyclotron]"
in view of the great loss to physics and the world, Acting
Secretary of War Kenneth C. Royall replied:
It is unsound to intimate that scientists are citizens of
the world alone, are internationalist and not loyal to
their native lands and are never willing participants in
the ambitions of dictators or tyrants. The evidence to the
contrary is too overwhelming for the American public to
accept this thesis, for modern war is scientific and total
war in toto. Without the scientist or the technical worker
the terrible instruments of destruction of the present day
would not have been possible.
In the interests of the country and of the American
scientists themselves, I believe you should exert your
influence to prevent any campaign for the restoration of a
cyclotron to the Japs at this time. ...
The Riken was dissolved "as a result of the defeat," although
Nishina later raised money to reestablish it on a different
footing. Elsewhere in Japan, physicists were restrained from
atomic research, and allowed only to work on applications to
biology and medicine. But without the big equipment to support
pioneering work, Japanese physics did not reattain the prominence
it had in the 1930's.
Could the Japanese have had an atomic bomb in World War II?
All the historians, Japanese and American, echo the conclusion of
the Physics Colloquium, that Japan did not have the uranium,
resources, or organization for a full-scale Manhattan-style
project. So the danger -- as turned out to be the case with the
Germans -- was not a real one.
But the historical importance of the project lies not in the
fact that Japan failed but that she tried, and that Japan's
postwar attitude that she, as the one nation victimized by atomic
weapons, is above seeking to acquire them for herself, is not
historically accurate. The historical record shows -- on the
basis of the eagerness of her military and the willing
cooperation of her scientists -- that if other factors had made a
bomb possible, the leadership -- which by the end of the war were
placing their own youth in torpedoes to home them on the
advancing U.S. fleet -- would not have hesitated to use the bomb
against the United States. -- Deborah Shapley
*G. Thomas and M.M. Witts, Enola Gay (Stein & Day, Briarcliff
Manor, N.Y., 1977). $11.95.
--------------------[First insert (p. 153:2)]--------------------
Derek de Solla Price, Avalon Professor of the History of Science
at Yale, with Eri Yagi Shizume, a Yale graduate student,
investigated Japan's wartime atomic bomb effort and published a
letter in the Bulletin of the Atomic Scientists in 1962, seeking
more information on the project. But none was forthcoming.
Price believes the effort was serious enough to "change the moral
and ethical relationship between Japan and the United States."
"Japan's attempt to acquire an atomic weapon during the World
War II changes the moral and ethical relationship between Japan
and the United States that has grown up over the use of the
atomic bomb against Japan. The story has been that the Americans
were guilty and the Japanese were innocent and blameless; that
the Americans developed this terrible new weapon and proceeded to
commit an atomic rape of the then-helpless Japanese."
"But the fact that the Japanese were trying to develop the
bomb, too, means that America was in an arms race with Japan as
much as she was with Germany."
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