He is a cheerful old farmer who jokes as he serves rice cakes made by his wife and then he switches easily to explaining what it is like to cut open a 30-year-old man who is tied naked to a bed and dissect him alive, without anesthetic:
"The fellow knew that it was over for him and so he didn't struggle when 'they led him into the room and tied him down," recalled the 72-year-old farmer, then a medical assistant in a Japanese army unit in China in World War II. "But when I picked up the scalpel, that's when he began screaming. ‘I cut him open from the chest to the stomach and he screamed terribly and his face was all twisted in agony. He made this unimaginable sound, he was screaming so horribly. But then finally he stopped. This was all in a day's work for the surgeons, but it really left an impression on me because it was my first time."
Finally, the old man, who insisted on anonymity, explained the reason for the vivisection: The prisoner, who was Chinese, had been deliberately infected with the plague as part of a research project. The full horror of which is only now emerging, to develop plague bombs for use in World War II. After infecting him, the researchers decided to cut him open to see what the disease does to a man's inside. That research program was one of the great secrets of Japan during and after World War II: a vast project to develop weapons of biological warfare, including plague, anthrax, cholera and a dozen other pathogens. Unit 731 of the Japanese Imperial Army conducted research by experimenting on humans and by "field testing" plague bombs by dropping them on Chinese cities to see whether they could start plague outbreaks. They could.
A trickle of information about the germ warfare program has turned into a stream and now a torrent. Half a century after the end of the war, a rush of books, documentaries and exhibitions are unlocking the past and helping arouse interest in Japan in the atrocities committed by some of Japan's most distinguished doctors. Scholars and former members of the unit say that at least 3000 people and by some accounts several times that number were killed in the medical experiments; none survived. No one knows how many died in the "field testing" It is becoming evident that the Japanese officers in charge of the program hoped to use their weapons against the United States. They proposed using balloon bombs to carry disease to America and they had a plan in the summer of 1945 to use kamikaze pilots to dump plague infected fleas on San Diego. The research was kept secret after the end of World War II in part because the U.S. Army granted immunity from war crimes prosecution to the doctors in exchange for their research data.
Japanese and U.S. documents show that the United States helped cover up the human experimentation and instead of putting the ringleaders on trial, it gave them stipends. The accounts now emerging are wrenching to read even after so much time has passed: a Russian mother and daughter reportedly left in a gas chamber, for example, as doctor’s peer through the thick glass and time their convulsions, watching as the woman sprawls over her child in a futile effort to save her from the gas.
Japan's biological weapons program was born in the 1930s, in part because Japanese officials were impressed that germ warfare had been banned by the Geneva Protocol of 1925. If it was so awful that it had to be banned under international law, the officers reasoned, it must make a great weapon. The Japanese army, which was then occupying a large area of China, evicted the residents of eight villages near the city of Harbin in Manchuria to make way for the headquarters of Unit 731. One advantage of China, from the Japanese point of view, was the availability of research subjects on whom germs could be tested. The subjects were called marinas, or logs, and most were Communist sympathizers or ordinary criminals. The majority was Chinese, but there were also many Russian expatriates living in China.
Takeo Wane, 71, a former medical worker in Unit 731 who now lives in the northern Japanese city of Morioka, said he once saw a 6-foot high glass jar in which a western man was pickled in formaldehyde. The man had been cut into two pieces, vertically, and Wane guesses that he was a Russian because there were many Russians then living in the area. The Unit 731 headquarters contained many other such jars with specimens. They contained feet, heads, and internal organs, all neatly labeled. "I saw samples with labels saying 'American,' 'English' and 'Frenchman,' but most were Chinese, Koreans and Mongolians" said a Unit 731 veteran who insisted on anonymity.
Medical researchers also locked up diseased prisoners with healthy ones; to see how readily various ailments would spread. The doctors locked others inside a pressure chamber to see how much the body can withstand before the prisoner's eyes popped out of their sockets. Victims were often taken to a proving ground called and, where they were tied to stakes in a pattern and then bombarded with test weapons to see how effective the new technologies were.
Planes sprayed the zone with a plague culture or dropped bombs with plague-infested fleas to see how many people and at what distance from the center would die. The Japanese army regularly conducted field tests to see whether biological warfare would work outside the laboratory. Planes dropped plague-infected fleas over Ningbo in eastern China and over Changed in north-central China and plague outbreaks were later reported. Japanese troops also dropped cholera and typhoid cultures in wells and ponds, but the results were often counterproductive. In 1942, germ warfare specialists distributed dysentery, cholera and typhoid in Zhejiang Province in China. But Japanese soldiers themselves became ill and 1,700 died of the diseases, scholars say.
Sheldon Harris, a historian at California State University, in Northridge, estimates that more than 200,000 Chinese were killed in germ warfare field experiments. Harris, author of a book on Unit 731, "Factories of Death" also says that plague-infected animals were released as the war was ending and caused outbreaks of the plague that killed at least 30,000 people in the Harbin area from 1946 through 1948.
The leading scholar of Unit 731 in Japan, Keiichi Tsuneishi, is skeptical of such numbers. Tsuneishi, who has led the efforts in Japan to uncover atrocities by Unit 731, says that the attack on Ningbo killed about 100 people and that there is no evidence for huge outbreaks of disease set off by field trials. Many of the human experiments were intended to develop new vaccines or treatments for medical problems the Japanese army faced.
Many experiments remain secret, but an 18-page report prepared in 1945 and kept by a senior Japanese military officer until now includes a summary of the unit's research. The report was prepared in English for U.S. intelligence officials and it shows the extraordinary range of the unit's work. There are scores of categories that describe research about which nothing is known. It is unclear what the prisoners had to endure for entries like "studies of burn scar" and "study of bullets lodged in the brains."
Scholars say that the research was not contrived by mad scientists and that it was intelligently designed and carried out. The medical findings saved many Japanese lives, for example, Unit 731 proved that the best treatment for frostbite was not rubbing the Limb, which had been the traditional method but immersion in water a bit warmer than 100 degrees, but never more than 122 degrees. The cost of this scientific breakthrough was borne by those seized for medical experiments. They were taken outside and left with exposed arms, periodically drenched with water, until a guard decided that frostbite had set in. Testimony from a Japanese officer said this was determined after the "frozen arms, when struck with a short stick, emitted a sound resembling that which a board gives when it is struck."
A booklet just published in Japan after a major exhibition about Unit 731 shows how doctors even experimented on a three-day-old baby, measuring the temperature with a needle stuck inside the infant's middle finger: "Usually a hand of a three-day-old infant is clenched into a fist", the booklet says, "but by sticking the needle in, the middle finger could be kept straight to make the experiment easier".
The human experimentation did not take place just in Unit 731, nor was it a rogue unit acting on its own. While it is unclear whether Emperor Hirohito knew of the atrocities, his younger brother, Prince Micas, toured Unit 731's headquarters in China and wrote in his memoirs that he was shown films showing how Chinese prisoners were "made to march on the plains of Manchuria for poison gas experiments on humans." In addition, the recollections of Dr. Ken Yuasa, 78, who still practices in a clinic in Tokyo, suggest that human experimentation may have been routine even outside Unit 731. Dr. Yuasa was an army medic in China, but he says he was never in Unit 731 and never had contact with it, nevertheless.
Dr. Yuasa says that when he was still in medical school In Japan, the students heard that ordinary doctors who went to China were allowed to vivisect patients. And sure enough, when Dr. Yuasa arrived in Shanxi Province in north central China in 1942, he was soon asked to attend a "practice surgery." Two Chinese men were brought in, stripped naked and given general anesthetic. Then Dr. Yuasa and the others began practicing various kinds of surgery: first and appendectomy, then an amputation of an arm and finally a tracheotomy. After 90 minutes, they were finished, so they killed the patient with an injection. When Dr. Yuasa was put in charge of a clinic, he said, he periodically asked the police for a Communist to dissect, and they sent one over. The vivisection was all for practice rather than for research, and Dr. Yuasa says they were routine among Japanese doctors working in China in the war. In addition, Dr. Yuasa - who is now deeply apologetic about what he did - said he cultivated typhoid germs in test tubes and passed them on, as he had been instructed to do, to another army unit. Someone from that unit, which also had no connection with Unit 731, later told him that the troops would use the test tubes to infect the wells of villages in Communist-held territory.
In 1944, when Japan was nearing defeat, Tokyo's military planners seized on a remarkable way to hit back at the American heartland: they launched huge balloons that rode the prevailing winds to the continental United States. Although the American Government censored reports at the time, some 200 balloons landed in Western states, and bombs carried by the balloons killed a woman in Montana and six people in Oregon. Half a century later, there is evidence that it could have been far worse; some Japanese generals proposed loading the balloons with weapons of biological warfare, to create epidemics of plague or anthrax In the United States. Other army units wanted to send cattle plague virus to wipe out the American livestock industry or grain smut to wipe out the crops.
There was a fierce debate in Tokyo, and a document discovered recently suggests that at a crucial meeting in late July 1944, it was Hideki Tajo - whom the United States later hanged for war crimes - who rejected the proposal to use germ warfare against the United States.
At the time of the meeting, Tajo had just been ousted as Prime Minister and chief of the General Staff, but he retained enough authority to veto the proposal. He knew by then that Japan was likely to lose the war, and he feared that biological assaults on the United States would invite retaliation with germ or chemical weapons being developed by America. Yet the Japanese Army was apparently willing to use biological weapons against the Allies in some circumstances.
When the United States prepared to attack the Pacific island of Saipan in the late spring of 1944, a submarine was sent from Japan to carry biological weapons of unknown type to the defenders. "The submarine was sunk", Professor Tsuneishi says, and the Japanese troops had to rely on conventional weapons alone. As the end of the war approached in 1945, Unit 731 embarked on its wildest scheme of all. Codenamed Cherry Blossoms at Night, the plan was to use kamikaze pilots to infest California with the plague. Toshimi Mizobuchi, who was an instructor for new recruits in Unit 731, said the idea was to use 20 of the 500 new troops who arrived in Harbin in July 1945. A submarine was to take a few of them to the seas off Southern California, and then they were to fly in a plane carried on board the submarine and contaminate San Diego with plague-infected fleas.
The target date was to be Sept. 22, 1945. Ishim Obata, 73, who now lives in Ehime prefecture, acknowledged that he had been a chief of the Cherry Blossoms at Night attack force against San Diego, but he declined to discuss details. "It is such a terrible memory that I don't want to recall it," he said.
Tidal Ishimaru, also 73, said he had learned only after returning to Japan that he had been a candidate for the strike force against San Diego. "I don't want to think about Unit 731," he said in a brief telephone interview.
"Fifty years have passed since the war. Please let me remain silent."