Unit 731

by Hal Gold

  The Japanese navy had submarines nicknamed "underwater aircraft carriers," which could generally hold from one to three seaplanes inside watertight compartments at deck height under their conning towers. When the subs surfaced, the hangar compartments opened into launch catapults. When the planes landed, they came alongside their mother ships, and they were hoisted back aboard with winches. The 1-400 submarine, the only ship of its class, was a large sub capable of carrying three planes. This boat was earmarked for the attack on America's west coast.

  The sub had a displacement of 3,530 tons, an underwater speed of six and a half knots, and a surface speed of eighteen knots. It was diesel-powered and snorkel-equipped, so that its combustion engines could run even while the boat was submerged. This characteristic enabled it to use one of its two engines for propulsion, while it charged its batteries with the other. At sixteen knots on the surface, it had a normal range of thirty-one thousand nautical miles. Its range could be extended by filling the ballast tanks with fuel oil instead of water. Filling the ballast tanks would, of course, mean that the sub could not surface until after a sufficient amount of fuel had been consumed, but Allied air and naval presence in the Pacific in the early part of 1945 would make submerged travel prudent at any rate. Reaching the American mainland seemed to be no problem, at least as far as technology was concerned.

  All discussion of the ultra-secret plan, first proposed toward the end of December 1944, was confined to a special tactical room set aside at the headquarters of the Naval General Staff in Hibiya, Tokyo. There were two main drawbacks to conducting this operation as a purely naval venture. One was a lack of data regarding the intended pathogens. The other was a lack of the pathogens themselves. For this, the nation's highest authority on biological warfare was called in, and Ishii became special advisor to the top army man in the project, Colonel Hattori Takushiro. One might imagine Ishii's anticipation as he envisioned American high-density population centers filled with agony, with citizens turning to blackened corpses. It would be a larger-scale success of— indeed a capstone to—his attacks on Chinese cities and villages.

  The plan was initiated as a joint army-navy project under the code name "Operation PX." It called for the sub to approach the American shore, then launch its planes and spread plague, cholera, and perhaps other pathogens from the air. The submarine crews would run ashore carrying germs. The entire attack was planned as a suicide mission.

  The project moved forward from a foundation of biological warfare intelligence provided by Ishii and Unit 731, and the plan was finalized on March 26, 1945. Then, at the last moment, General Umezu Yoshijiro, Chief of the General Staff, stepped in and ordered the plan scrapped. He reasoned that "if bacteriological warfare is conducted, it will grow from the dimension of war between Japan and America to an endless battle of humanity against bacteria. Japan will earn the derision of the world."

  The officers working on the attack plan objected fiercely, but Umezu's decision prevailed. There is little doubt that an American city would have been another Ningbo on a larger scale.

  Interestingly, about two weeks before the finalization of the plan, America brought a new weapon into the war with an incendiary attack on a large, lower-class neighborhood of Tokyo. Even among the almost continuous air raids over Japan, the Great Tokyo Air Raid had been the most devastating so far, with an estimated one hundred thousand civilians burned to death by a combination of conventional incendiaries and America's new contribution to modern weaponry, napalm. Even this failed to deter Umezu from his veto of a germ attack on America.

  General Umezu was later given the inglorious duty of representing Japan's army in signing the instrument of capitulation aboard the U.S.S. Missouri. At first he refused, then agreed to go only if it were considered a direct order from the emperor. Umezu was later tried for and found guilty of war crimes at the Tokyo War Crimes Trials. His single-handed prevention of the bacteriological attack on America never surfaced there.

  In August 1947, the Chief of Naval Intelligence in Washington released a top-secret, hundred-page-long document entitled "Naval Aspects of Biological Warfare." It was produced in cooperation with the Biological Warfare Section of the Intelligence Division of the War Department General Staff to "present as accurate a picture as possible" of the material it covered. It discussed biological warfare research in major countries such as the United States, Great Britain, Germany, Italy, the Soviet Union, and Japan. The report asserted: "It is doubtful if humanitarian principles have ever been responsible for failure to employ man-made epidemics."

  Ironically, the Naval Intelligence report came out about halfway through the Tokyo trials, where Umezu was sentenced to life in jail. The secret died with him at Sugamo Prison in 1949.

  Covering the Traces

  As the end of the war loomed, Japan came to expect a Soviet thrust into Manchuria, and the facilities of Unit 731 and its branch units were blown up to destroy evidence of their existence and the horrors they had perpetrated. At Zhongma, the construction was so superb that its destruction was difficult. Calling it a "fortress" was no exaggeration; while the installation was built for the purpose of research and development, it obviously had the structural strength to withstand attack.

  Pingfang, the center at Dalian, and other units were destroyed, but other facilities remain standing to this day. The staunch building in Nanjing that served as home to Unit 1644, sometimes called the Tama Unit, is now used is a hospital. People can visit the rooms on the second floor where rats and fleas were once raised. They can visit the third floor, where infected maruta were dissected, admission was permitted only to authorized persons wearing protective clothing and masks, and disinfection at the doorway was required. They can visit the fourth floor, which was a prison.

  Skeleton crews stayed behind in China to carry out the destruction, while the major part of the staff and their families, feeling the Soviets' breath upon their necks, cleared out. The South Manchuria Railway was efficient to the end. A special train carried unit members from Harbin and Pingfang, then traveled south, through the Korean peninsula. After crossing to Japan by sea, they took another special train north through Kanazawa, where some members reportedly used the Noma Shrine for a hideout. The special train continued on to Niigata Prefecture, at which point the members split up and used regular public transportation.

  In Manchuria, Ishii boarded the train for one leg of the journey, during which he set forth his rules that members were not to take jobs in public offices, were not to contact each other from then on, and were to "take this secret to the grave." He took films and records with him, and returned to Japan by plane.

  At Pingfang today, remnants of the fortress still remain, preserved as a monument to human inhumanity. The massive double stacks of the boiler room stand like a morbid tombstone, and seem to hang on to existence just as thousands of captives there must have hung on until the end, hoping that something, somehow would save them—or part of them—from destruction. The Pingfang fortress of the medical inquisition is clinging to life, keeping the memory of screams, cries, and death agonies from disappearing completely.

  American Occupation

  As the end of the war brought Allied forces and civilian personnel to Japan by air and sea, a new chapter was about to begin for Unit 731. The postwar story of the outfit begins in September 1945, with the docking of the American ship Sturgess in Yokohama. Among those on board was Lieutenant Colonel Murray Sanders. A highly regarded microbiologist who had been a lecturer at Columbia University, Sanders had entered the military and been attached to Camp Detrick (later Fort Detrick) in Maryland, the American military's center for biological weapons research and development. The work done there would have been at the heart of retaliation which President Franklin Delano Roosevelt had threatened for what he termed Japan's "inhumane form of warfare" in China through biological weaponry.

  As the Sturgess worked its way toward the western part of Tokyo Bay and the port of Yokohama, Naito Ryoichi waited on th
e pier. Naito, one of the men closest to Ishii, and the number-two man in Ishii's research laboratory in Tokyo, already had a history of duplicitous dealing with foreigners. Before the war, he had studied in Germany and in the U.S., at the University of Pennsylvania. During his stay in America, he had walked into the Rockefeller Institute in New York with a letter of introduction from the Japanese embassy in Washington and a request for samples of yellow fever virus. His reason for the request, he had explained to the people at the institute, was that upon his return to Japan, he would be working for the Japanese army in Manchuria in developing a vaccine for the disease. When the Americans refused, perhaps because of mounting U.S.-Japanese tensions over the latter country's aggression in China, he attempted to resort to bribery. In the end, he came back to Japan without the yellow fever viruses.

  Back in Japan, Naito wrote up secret reports on ways of increasing the virulence of pathogens, methods of bacteriological warfare, and other subjects that were being handled in the Ishii organization.

  As the crew of the Sturgess threw the ship's berthing lines onto the dock, Naito purposefully awaited it, ready to play his role in launching Unit 731 into its postwar odyssey. Japan's information network had found out that Sanders would be on board, and that he would be in charge of investigating Japan's biological warfare activities. Years later, Sanders himself described the scene this way in an interview: "My mission was biological warfare.

  I was to find what the Japanese had done, and when the Sturgess docked in Yokohama, there was Dr. Naito. He came straight toward me. He seemed to have had a photograph of me, and said that he was my interpreter."

  "Did you know at that time," Sanders was asked, "that he was a member of Unit 731?"

  "I didn't even know what 731 was."

  Sanders installed himself in his office and started his job of meeting with Japanese believed to be concerned with research into and/or actual employment of biological warfare. And from there, with the dust of World War II still hanging over Tokyo, a new contest started. Rather than making offensive war against its enemies, Unit 731 now went on the defensive against the occupation forces. The data gained from human experimentation once again became ammunition: this time in the bargaining room, rather than on the battlefield. The Japanese hoped to use their knowledge as a tool for gaining freedom from prosecution as war criminals.

  Sanders offered other memories of Naito, too: "He was a very humble, shy person . . . very careful. He went home every night and came back the next morning. If you're interested, I found out later that he didn't go home, but went to the various Japanese headquarters." At those offices, Naito conferred with others on what information should be given to Sanders, and what should be withheld. Naito also kept the Japanese officials apprised of the content and progress of his discussions with Sanders. Naito's purpose was to get between Sanders and anyone connected with Unit 731 with whom Sanders came into contact. For this reason, the American failed to make any considerable amount of progress. Naito, the interpreter-cum-information filter, was sometimes evasive, sometimes contradictory in this game of cat-and-mouse.

  At last, Sanders was up against a wall and told Naito that if things continued the way they were going, the Communists would be coming into the picture. "I said that," Sanders recounts in the interview, "because the Japanese exhibited a deadly fear of the Communists, and they didn't want them messing around. He appeared the next morning with a manuscript which contained startling material. It was fundamentally dynamite. The manuscript said, in essence, that the Japanese were involved in biological warfare." The document, Sanders stated, gave the line of command of the Japanese military, with all the departments "implicated, plus or minus." Obviously, as much as America wanted the information, the Japanese had an equal interest in avoiding the "justice" of the Soviet legal system, at whose hands their fate would be easy enough to predict. His gambit appeared to have succeeded.

  Sanders took the document to General Douglas Mac-Arthur, the Supreme Commander for the Allied Powers (SCAP), and from there the balance of options was weighed. There was information that America wanted, and on an exclusive basis. That would mean America's turning its back on the forthcoming war crimes trials and striking a deal, independently of the judiciary proceedings, with the men who had the data. Sanders recalls MacArthur as having said, "Well, if you feel that you cannot draw out the information, we are not given to torture." So, deprived of the stick of physical duress, the American microbiologist went back to Naito with a carrot instead. MacArthur would assure Naito that in exchange for the information, the informants would not be brought to trial. "This made a deep impression, and the data came in waves after that... we could hardly keep up with it."

  In December 1994, a written record of several meetings that took place between Sanders and top-echelon Japanese officers surfaced in the home of an eighty-four-year-old Japanese former staff officer. It was published in the Spring 1995 issue of the Japanese quarterly magazine Senso Sekinin Kenkyu (The Report on Japan's War Responsibility), with the agreement that the owner's identity remain confidential. The record was written in Japanese by the Japanese interpreter at the meetings, and excerpts appeared in the article. The meetings took place at MacArthur's headquarters in the Dai-Ichi Sogo Building on October 9, 11, and 16, 1946. The interpreter for the first two meetings is listed as Kamei Kan'ichiro, "a member of the House of Representatives with very strong ties to unit leader Ishii." (Kamei's continuing involvement with postwar Unit 731 members and their bargaining efforts belies claims over the years that the government was in the dark about Ishii's activities.) Questioning proceeded along the lines of how and why the unit was formed, development of different types of biological warfare bombs and outdoor tests of these, what happened at the time of the Soviet invasion of Manchuria, the system of culturing bacteria using incubators, production of vaccine, and other germane issues.

  The article in the journal simply lists the names of the participants in the exchange as "S," "M," and "N." The first two letters are explained explicitly as referring respectively to Sanders and a Colonel Masuda Tomosada, who had served with Unit 731 in Manchuria from 1945. "N" is left unexplained, but could only be Naito since he, with his English ability, had been maneuvering questioning all throughout the postwar investigations and had attended many of the sessions with Sanders (whether wanted or not). The term "BK" in the Japanese notes is deduced by the author of the article to mean development of biological weapons. This is an excerpt from the notes of the meeting of October 9, 1945:

  N: I brought Colonel Masuda with me, the man we spoke of the other day . . .

  S: Did you not engage in BK research?

  M: Yes, I did.

  S: I would like you to tell me about that biological warfare research.

  M: I know about BK and will gladly talk about it, but first I want to mention that what I am about to say is my own opinion. I believe that you will not use it for political reasons.

  I know that you [Sanders] spoke yesterday with Lieutenant Colonel "N", and I feel secure in speaking freely about this now.

  The transcript of this meeting notes that "the 'statement' made to Lieutenant Colonel Naito in this investigation is data for a secret report to the [American] president. It is not to be revealed. Rather, if a problem concerning BK arises among the various countries, America's knowing our situation can dispose of the problem to Japan's advantage. This is not concerned with the question of searching out war criminals." This shows that the proposal—made with the involvement of the American president—to grant immunity from war crimes was already on the table less than two months after the war's end.

  While Naito was capable of using and disposing of human beings with no more compassion than scientists extend to lab rats, superficially he appeared to have much in common with Sanders. Both men, after all, were researchers, not military men, and yet both had ended up soldiers and even attained the same rank of lieutenant colonel. Thus, the main players in the crucial first encounter between Americ
an authorities and Unit 731 seem to have interacted not on the basis of victor and vanquished, but more like peers: Sanders the scholar looking through his colleague Naito's microscope. Naito, a mild-mannered man described as "friendly" even by a Singaporean who had worked for him cultivating rats, was also crafty enough to play ping-pong with the information Sanders wanted, so that Sanders' first reports on his investigations advised his superiors that biological warfare in the Japanese army had been an "unimportant minor activity." He covered himself though, by expressing doubt that all had been revealed.

  Shortly after the initial doors of information had been pried open by Sanders' threat of the Communists' participation in the investigations, and knowing that Mac-Arthur had promised immunity to former members of Unit 731, Ishii felt sufficiently protected to come out from hiding. Then, while the Allies were tied up with the burden of preparing for the upcoming war crimes tribunal, Ishii was placed under house arrest. There, he was made available for questioning by the successor to Murray Sanders, Lieutenant Colonel Arvo Thompson.

  Sent by Camp Detrick to continue the investigation into biological warfare activities, Thompson was not as soft as Sanders, not so easy to brush off with evasive answers. Thompson reached closer to the scope of the experiments but the magnificence of Ishii's organizational skills and the scale of the unit's operations eluded him, as well. He concluded that civilian scientists and research facilities were not involved.

  One thing the Japanese have demonstrated throughout history is their ability to form complex—at times, frustratingly byzantine—organizations to coordinate complicated activities. Feudal Japan in the seventeenth through nineteenth centuries was made up of some two hundred fifty feudal domains (the number fluctuating as new ones were created, others abolished) with a complex and clearly defined bureaucracy at the center. No European country had such a precision-cut hierarchy of interknit functions and responsibilities. The shogunate also organized what is considered the world's first secret police as an arm of government, as well as an espionage network. The fact that Japan had a fully developed money economy by the early seventeenth century—even to the point of using a variety of paper credits in major business transactions—is another indication of an advanced sense of organization.