(8/18/2013: Part 2 has been uploaded. They knew the B29 headed for Hiroshima was carrying the atomic bomb, they knew the B29 headed for Nagasaki was carrying the atomic bomb. They knew hours in advance.)
There is an NHK documentary that was aired two years ago on August 6, 2011, on the anniversary day of Hiroshima atomic bombing. I was unaware of this documentary until I saw a tweet a few days ago that had the link to a blogpost by Councilman Koichi Ohyama of Minamisoma City, Fukushima on September 25, 2012.
Mr. Ohyama's post from one year ago quotes the NHK documentary's announcement from two years ago, which says that the top officers of Japanese imperial army knew in advance the impending US attacks on Hiroshima and Nagasaki, and did not do anything.
Atomic bomb attacks on Hiroshima and Nagasaki have been described (at least in Japan) as "beyond expectation" (just like the Fukushima nuclear accident) and "surprise attacks" with no pre-warning by the US, who used to dump leaflets in Japanese from the planes to warn civilians of impending attacks.
But NHK says the top military officers in imperial Japan knew, and did nothing. The military essentially was the government during the war.
I had never heard of such a thing.
So I looked for the video of this documentary and watched it.
原爆投下 活（い）かされなかった極秘情報 by gataro-clone
To share what I learned with readers who do not speak Japanese, the following is my first-pass translation (not all strictly literal, subject to revision; links added for reference) from the NHK documentary titled "Atomic bombing - top secret information that was never utilized (原爆投下 活かされなかった極秘情報)", aired on August 6, 2011. Since the documentary is one-hour long, I have broken up into two parts with my summary for each, for easier reading.
Summary of Part 1:
Atomic bombing of Hiroshima and Nagasaki has been considered "beyond expectation", "surprise attack". However, the General Staff Office of the Japanese Imperial Army knew about the secretive US activities on Tinian Island in the Northern Mariana Islands since June 1945. The special intelligence unit directly controlled by the General Staff Office had been monitoring the code signs of B29s on the Northern Mariana Islands, and it noticed the peculiar code signs of about a dozen B29s that suddenly appeared on the island of Tinian in June 1945, two months before the atomic bombing of Hiroshima and Nagasaki. The intelligence unit sensed these planes were on some unknown, special mission. The information was quickly shared with the top military officials.
Japan had been aware of the US efforts to develop atomic bombs, and it had started its own efforts to develop atomic bombs in 1943. But when the government had to abandon the effort in June 1945, it convinced itself that uranium extraction was impossible for anyone, including the United States. The Japanese government had information on successful detonation of the first atomic bomb on July 16, 1945 in New Mexico, but it again convinced itself that it couldn't be an atomic bomb.
The intelligence unit continued to monitor B29s with V600 call signs and kept informing the top officials. They did not connect the dots, and the mysterious B29s on Tinian Island remained mysteries as the fateful August 6, 1945 approached.
Tinian Island in the Northern Mariana Islands. August 6, 1945. North Field. Secret B-29 planes was about to depart, to drop the "special bombs" - atomic bombs on Japan.
An atomic bomb was dropped on Hiroshima. Three days later, the same happened in Nagasaki.
So far, the atomic bombing in Hiroshima and Nagasaki is considered to have been utterly "beyond expectation" for the Japanese, "surprise attacks". However, in fact, the Japanese military intelligence unit had known in advance the US activities surrounding the atomic bombing. They were monitoring the US military communications.
NHK has uncovered what little information left on the matter, and found eyewitnesses, diaries, audio tapes of the deceased officers in charge of intelligence. What NHK has found out is the fact that the military knew the danger was imminent but nothing was done.
The military intelligence unit had started tracking what they called "special task planes" which became active in June 1945 on Tinian Island, two months before the atomic bombing. On August 6, 1945, they knew the movement of the bomber approaching Hiroshima.
In case of Nagasaki, the top officers of the military knew the bomber was approaching Nagasaki, 5 hours before the bomb was dropped.
Was there anything that could have been done?
People who had been involved and who had said nothing since the end of the World War II have started to talk.
There was no air-raid siren. People were exposed to radiation and heat from the atomic bombs, without any protection. More than 200,000 people died in 1945 alone in Hiroshima and Nagasaki. Why was nothing done, when they had intelligence surrounding the atomic bombing?
For the first time in 66 years, here's the truth.
(5:02 - Intelligence)
The former headquarters of the special army intelligence unit in Suginami-Ward in Tokyo. Ryoji Hasegawa, 88, was a second lieutenant of the Japanese Imperial Army. He was told never to disclose even the existence of the unit, which became active in the spring of 1945. The unit was directly under the General Staff Office, charged with collecting the enemy intelligence. One of the tasks for Hasegawa was to collect information on B-29 bombers, as the US air raids using B-29 on Japan intensified in March 1945.
There were more than 100 members in the special intelligence unit. They were listening in on the Morse code used between the bombers and the bases. The messages were mostly encrypted, and deciphering was difficult. However, there was a short signal at the top that was not encrypted.
That was a call sign. It started with "V", followed by three digits, and that would let the receiver know who was sending the message.
The monitoring records of the Japanese military. Most of the records were destroyed after the war, but NHK found some that survived. Most call signs were from the Mariana Islands.
The special intelligence unit noticed that bombers from each island had different call signs. Saipan: V400s, Guam: V500s, and Tinian: V700s. By monitoring the call signs, they could tell how many bombers were coming from which island. The unit was able to predict where they were headed, by continuously monitoring the call signs.
Hasegawa: "We would collect the information, and tell the General Staff Office how many B29 bombers were likely to go which direction. 200 here, 300 there..."
(9:40 - V600 call signs from Tinian Island in June 1945)
June 1945. The special intelligence unit noticed something abnormal. They caught mysterious call signs that they had never heard before. Hasegawa says, "They were call signs in V600s. We'd seen 400s, 500s and 700s, and they come from Saipan, Guam, Tinian. But now, V600s. Something was wrong, we thought."
They were coming from Tinian Island. On the island that had been using call signs in 700s, there was now a new group of B29 bombers using call signs in 600s. What was their purpose? The unit strengthened its monitoring capability to watch closely.
Tinian Island was taken by the US in August 1944. North Field of Tinian Island, which was the base for Japan bombing raids. A special unit arrived there in June 1945 and started using call signs in V600s. It was the 509th Composite Group, which later dropped atomic bombs in Hiroshima and Nagasaki.
One of the Group was Mr. Russel Guggenbach (spelling is my guess), 88. He participated in the bombing of Hiroshima and Nagasaki as a crew member of B29. Mr. Guggenbach says the contact with other units was strictly forbidden on the island.
"The new commander informed us that there was going to be new officer, a new bomb was being developed, and if successful the bomb would shorten the war. We were told we were on the tight security, and we should obey orders and what we learned, what we saw, we learned to keep it ourselves. We were not supposed to tell even to our best friends."
The US was spending 2 billion dollars to develop atomic bombs.
There were about 10 B29s of this special unit on Tinian Island that used the call signs in V600s. Compared to other B29s that went on the air raids on Japan, 200 or 300 planes at a time, it was incredibly small. Guggenbach says they did the pin-point bombing practice in the nearby small islands, though they didn't know the final destination. All their training, says Guggenbach, "was for this special bomb, on a special mission."
(15:03 - How much did the top Japanese military officers know about this information?)
Major Eizo Hori was in charge of providing intelligence collected by the special intelligence unit to the top officers in the General Staff Office. He died 16 years ago, but according to his family he had always blamed himself for not being able to stop the atomic bombing. His family kept an audio tape that Hori made several years before his death, about the special unit on Tinian Island.
"Unit with the call signs in 600s, it was a mysterious unit. When we followed the numbers carefully, we found that there were only 12 or 13 of them. So far, B29s were in hundreds. Something was wrong. We started to call them "special task plane". Something was very wrong, and we did our best to keep track of them..."
Major Hori's information of the "special task planes" was conveyed all the way to the top of the General Staff Office. However, Hori said he didn't know at that time that the "special task" was atomic bombing.
(17:57 - What the military/Hideki Tojo knew about the US atomic bomb development)
Japanese Imperial Army had known from early on that the US had been developing nuclear bombs. In the spring of 1943, General Hideki Tojo, who was then the Minister of War, spoke to people in charge of weapon development. He said,
"We also have information that the development of atomic bombs is in an advanced stage in the US. This development may decide the fate of the war."
General Tojo then ordered the aviation headquarters to start the development of atomic bombs.
The best and the brightest in the nation were gathered. One of them was Mr. Kunihiko Kigoshi, 92. He was in charge of developing the uranium compound to be used in the bombs. Dr. Yoshio Nishina of Institute of Physical and Chemical Research led the group of researchers including Mr. Kigoshi.
Mr. Kigoshi says Dr. Nishina was frequently called to the aviation headquarters of the Japanese Imperial Army to be asked about the progress on atomic bomb development.
"After Dr. Nishina returned from the aviation headquarters, we were called to his office and told to do our best. I believe he was under significant pressure from the Army."
In the mountainous region of Fukushima Prefecture, uranium ore was being mined by school students. Mr. Kiwamu Ariga, 80, was one of the students mobilized for the war efforts to mine uranium. He and his fellow students mined, and then transported uranium ore on their backs.
One day, to inspire the students doing the harsh labor, an army officer came and spoke to the students. Mr. Ariga says,
"The officer told us that a bomb will be made from the stones we were carrying. He said a small matchbox-size [bomb] would destroy a large city like New York in an instant. So keep up your effort, said the officer."
However, the Imperial Army gave up on developing the atomic bomb at the end of June, 1945. It was due to lack of materials and resources, as the US air raids became too frequent.
But that was not the reason cited in an Army report. The report said, "It turned out that it was impossible to extract radioactive uranium. In the US, they came to the conclusion that it was impossible."
As an excuse for discontinuing the development, the Army made a baseless assertion that even the US couldn't do it [extract uranium]. [This is by NHK's narrator - i.e. NHK's opinion.]
Mr. Kigoshi says,
"They had to have a reason for discontinuing. If they thought the US might succeed, that would mean Japan would totally lose. The environment was such that it prohibited that kind of thought from entering into people's minds."
(23:27 - The US succeeds in the first atomic bomb detonation in New Mexico)
But right after Japan halted the development of atomic bombs, the US carried out the first successful atomic bomb experiment in New Mexico on July 16, 1945. Fragments of this information were delivered to the General Staff Office. But no one dared admit it was an atomic bomb.
After the war, the Ministry of Foreign Affairs compiled the history of the war. A person who served as secretary to the Minister of War wrote a memo on the incident:
"We had the report of a new weapon tested in New Mexico that had large explosive power. But no one thought it was an atomic bomb."
Mr. Kigoshi, who was involved in Japan's effort to develop atomic bombs, says it was impossible for the top Army officers not to know it was an atomic bomb.
"Of course, even at that time, they must have thought the bomb was utilizing nuclear fission, I believe. Japan's development effort was just too small-scale. I thought it would be the US who would succeed."
The Imperial Army refused to recognize that the US had succeeded in developing an atomic bomb. Mysterious B29s on Tinian Island, dubbed "special task planes" by the Japanese intelligence, remained mysterious. The fateful day approached.
(To be continued in Part 2 of the post)