Unit 731

by Hal Gold

  Ishii's empire was, in a sense, a mirror image of the feudal webwork, even down to the police network. Lingering Confucian relationships between established researchers and their disciples meant that medical students were under the control of their instructors. Data from the prison/research cells circulating back through Tokyo and out to the nation's medical research facilities tied the military and civilian medical worlds together in a complicated, logical framework. The development of biological weapons was, in fact, sometimes a cover for ordinary medical research using extraordinary methods available to the Japanese only in the Ishii organization. This was one aspect of the machinery which eluded the Americans. The net was broad and deep, yet to the Americans, still invisible.

  Thompson left Japan without getting too much closer to reality. Back at Camp Detrick, his findings were evaluated but led to no firm conclusions.

  Superpower Jockeying

  Meanwhile, in the first week of May 1946, about four months after Ishii was first interviewed, the International Military Tribunal for the Far East convened. From initial appearances, it should have made sense for the Americans to want to question members of Unit 731. Indications of biological warfare activities by the Japanese had trickled into Allied hands even well before the end of the war. Also, Japanese POWs, many of whom had backgrounds in military hygiene and related fields, served as a significant source of accounts. Reports of Japanese biological warfare activities in China had even prompted a warning from the American president as early as 1943 that if they were not halted, the U.S. would retaliate "in full measure."

  Among other examples of American wartime discoveries of Japan's bacteriological warfare is an official U.S. research report titled "Japanese Violations of the Laws of War," dated June 1945. It catalogues some evidence of Japanese biological warfare, and it is certain that it reached the highest levels of the American government: one copy of the report was labeled "Personal copy for General of the Army Douglas MacArthur." It carries the statement of a prisoner captured on May 12, 1944. His family name of Rin would be Chinese, not Japanese, but he was listed as a Japanese POW of the Americans. He stated that he had been a civilian employee working in the Bacteriology Department of Chuzan University at Guangzhou, and was quoted in the report as saying that in June 1941, "he heard that Major General Ishii, Shiro was conducting experiments with bacillus bombs at branch of Army Medical College in Harbin, Manchuria. Previously, Major General Ishii had been head of Laboratory Section, Army Medical College at Tokyo."

  Other damning entries appear in the report, as well. One is an "extract from loose handwritten sheets containing fragmentary notes on various types of bombs. Undated and unclassified, owner and unit not stated, captured Philippine Islands, December 1944: MK-7 bacterial bomb (BYORYOKIN) 1 kilogram." Another item in the book shows a list of Japanese possessions falling into American hands. One such item is a printed manual of "Field Service and Supply" dated August 1941, and with "many pages missing." A section of this document is listed in the U.S. report as titled "Subject Matter—Bombing, Gas and Bacteria (these pages torn out.)"

  The end of the war did not mean an end to such reports. If anything, the volume of information arriving at SCAP headquarters exceeded that available during wartime, flowing in almost from the time of the beginning of the Occupation. Moreover, Joseph B. Keenan, chief of the International Prosecution Section (IPS), had received reports of biological warfare activities. Nonetheless, no action had yet been taken to investigate whether any of the participants in Japan's biological warfare activities should be called up before the tribunal.

  Moscow seemed to have stronger feelings on the issue than its ostensible ally Washington. With the trials underway, the prosecutor for the U.S.S.R. made a request to interview Ishii and two other leading researchers, Colonels Kikuchi and Ota, in connection with biological warfare experiments. Information from Japanese POWs captured by the Soviets in Manchuria had suggested to them a need to investigate Japan's biological warfare program further. The information that the POWs had supplied to the Soviets concerned experiments by these men using Chinese and Manchurians. The Soviets were assuming—or claiming to assume—that supplementary war crimes trials would be authorized by the United States. And, of course, they wanted to see all information relevant to Unit 731.

  The Soviets were interested in Ishii and his organization for three important reasons. One was the proximity of the unit's operations to Soviet territory. Next, of course, was the desire for revenge for Japan's use of biological warfare against Soviet soldiers. The third motivation was the prospect of obtaining grist for the propaganda mill. Whereas America wanted to forego trying some highly-educated medical researchers as war criminals as part of a quiet quid pro quo, the Soviets wanted to make noise.

  The request went to MacArthur's headquarters. On February 7, 1947, MacArthur sent a dispatch to Washington: "Prosecutor for USSR at IMTFE (International Military Tribunal Far East) requests permission to interrogate former Japanese General Ishii, Colonel Kikuchi, and Colonel Ota, all formerly connected with Bacteriological Warfare research . . . Request based on information . . . that experiments authorized and conducted by above . . . resulted in deaths of 2000 Chinese and Manchurians."

  "Opinion here," MacArthur continued, "that Russians not likely to obtain information from Japanese not already known to United States and that United States might get some additional information from Russian line of questioning in monitored interrogations." The contest of wits and information-maneuvering between America and Russia was on. Should the U.S., MacArthur asked the War Department, acquiesce to the Russian request?

  About six weeks later, toward the end of March 1947, permission came from the Joint Chiefs of Staff in Washington for a "SCAP-controlled Soviet interrogation" of Ishii, Kikuchi, and Ota. Before the U.S. let the Soviets get to them, however, Kikuchi and Ota were to be interviewed by competent American personnel. The War Department expressed its readiness to dispatch such personnel to Tokyo for a preliminary interrogation secret from the Soviets, then for monitoring the subsequent Soviet interrogation. If the preliminary interrogations brought out any important facts, the Japanese ex-officers were to be instructed not to reveal them to the Soviets, and also not to tell the Soviets that the preliminary interrogations had taken place. The Americans' line of reasoning in denying the Soviets unfettered access to the prisoners was that war crimes allegedly committed against Chinese did not represent a legitimate war crime interest for the Soviets, and that U.S. permission for the Soviets to conduct investigations should be considered to have been granted purely as a friendly gesture.

  MacArthur's office agreed to the dispatch of qualified personnel. Washington then informed SCAP that a Doctor Norbert H. Fell had been selected by the Chemical Warfare Service, and he would leave for Japan in the first week of April. Upon Fell's arrival in Japan, the same Kamei Kan'ichiro who had translated for Sanders pushed his way onto the scene to "assist." Immunity from war crimes had not yet been fully granted, though its possibility was hanging in the air. Kamei was hinting that there were people who had information which would prove of interest to the Americans, but they were not very willing to talk about it for fear of being brought into the trials. And this time, in a reversal of Sanders' tactic against Naito, Kamei made use of the Communist threat against the Americans.

  Kamei, according to Fell's report, claimed that he knew people formerly with Unit 731 who were afraid of giving information to the U.S. because the Russians would get hold of it. Holding out the incentive of Japanese silence before Red interrogators, Kamei said that those Japanese felt that the best thing for them now would be to tell Moscow nothing. These pragmatics aside, Kamei also resorted to a pious "we were victims" defense—that the Soviets had been engaging in biological warfare against the Japanese, and "we had to think about defensive measures." Japan, he claimed, knew about Soviet biological warfare work from captured Soviet spies in Manchuria, and there had been no other recourse for Japan but to work on defensive
biological warfare. Then, in the course of this research, they had discovered the offensive aspects.

  Meanwhile, anonymous and signed reports had been coming in to the American authorities in Tokyo from people who had been victims of the system, enlisted in one unsuspecting way or other into Ishii's research network. A limited few identified themselves, accusing Ishii and Wakamatsu, the veterinarian who had run Unit 100 in Xinjing.

  As information started coming into the hands of the American investigators, it came with attempts to conceal the organizational reach of the machinery of human experimentation; even as they confessed, the informants tried to save their own skins. Ishii, it was claimed, was a renegade having nothing to do with the legitimate line of command or military authority. The Japanese medical profession was not involved. The emperor knew nothing. People's consciences may have been smarting and moving them to come clean—but not to the point of suppressing the instinct for self-preservation, or their continuing loyalty to Emperor Hirohito.

  Fell met with some twenty people connected with biological warfare. Then, back at Camp Detrick, he compiled the results and conclusions of his mission and stated that the human experimentation conducted by the Japanese would provide valuable data. The Soviets, ever the ping-pong ball in the vying between Washington and Unit 731, appeared again, this time in Fell's report when he quoted Ishii as saying, "My experience would be a useful advantage to the United States in the event of a war with the Soviet Union."

  Three days after Fell's last report went off to Major General Alden Waitt, chief of the U.S. Army's Chemical Corps, MacArthur's office messaged the War Department that "Ishii states that if guaranteed immunity from 'War Crimes' in documentary form for himself, superiors and subordinates, he can describe program in detail.

  "Ishii claims to have extensive theoretical high-level knowledge including strategic and tactical use of BW on defense and offense, backed by some research on best BW agents to employ by geographical areas of Far East, [and] the use of BW in cold climates."

  The viability of bacteria—their ability to survive and thrive—is dependent upon their environment. Differences in the natural environmental conditions of various regions mean that bacteria developed in the United States, for example, may not do well in conditions in Asian areas, which would degrade their effectiveness as weapons. Ishii's statement shows that he had considered bacterial viability in relation to the various areas where his units were functioning. If Asia were to be a continuing area of military operation for the United States, biological weapons developed for Asian environments would be of interest.

  The Japanese knew by now that they had little to fear from the Americans in terms of raw hate retribution. During the war, Japanese civilians had been bombed, burned, and irradiated. American conduct from the beginning of the Occupation, though, had consistently demonstrated that the Japanese now would be treated in an orderly and compassionate manner. This feeling of security contrasted directly to what Japanese military leaders feared would happen to them at the hands of victorious Russians and Chinese, whose civilian populations had suffered worse atrocities. A message from MacArthur to Washington dated May 6, 1947 mentions clearly that "statements so far have been obtained by persuasion, exploitation of Japanese fear of USSR, and desire to cooperate with the US." America was showing interest in matters more practical than turning up defendants for war crimes trials.

  (Ironically, the Japanese were not entirely correct about who would mete out the most generous treatment in the wake of the war. The Soviet Union certainly justified Japanese fears of revenge, with tens of thousands of Japanese soldiers dying and disappearing at the hands of the Red Army, as it swept through Manchuria. The Chinese Communists, however, behaved much differently. In the oral history Japan at War, by Theodore and Haruko Cook, a former Japanese POW held by the Chinese Communists reports that "there were one thousand sixty-two of us altogether . . . Forty-five of us were indicted and the others were given a reprieve." By contrast, the same book reports that "of 4,000 arrested as war criminals by Allied nations in the Pacific and Asian theaters, 1,068 were executed or died in prison from 1946 to 1951." Another former POW remarks, "I really believe the Chinese Communist Party were the ones who spared my life.")

  At this point in time, the question of whom to prosecute in war crimes trials had not been completely settled. Testimony reported by the Soviets was convincing enough for IPS to inform the War Department of its opinion that it "warrants conclusion that Japanese BW group headed by Ishii did violate rules of land warfare, but this expression of opinion is not a recommendation that group be charged and tried for such," adding that corroboration and evaluation of the suspects and their testimony for trustworthiness would be necessary first. In favor of prosecution, MacArthur recognized that high-ranking Japanese liable for prosecution for war crimes were not necessarily the best sources of information. "A large part of data including most of the valuable technical BW information as to results of human experimentation and research in BW for crop destruction probably can be obtained in this manner from low echelon Japanese personnel not believed liable to 'War Crimes' trials."

  On the other hand, the general also clearly perceived benefits to be had from pardoning the higher ranking researchers. His feelings on this matter are particularly evident in his advice to the War Department that "additional data, possibly including some statements from Ishii probably can be obtained by informing Japanese involved that information will be retained in intelligence channels and will not be employed as 'War Crimes' evidence." In particular, immunity from prosecution "will result in exploiting the twenty years experience of the director, former General Ishii." Furthermore, acquiring information in this way would prevent it from coming out in courtroom testimony, which would enable the Soviets, among others, to gain access to it. This United States would become the sole recipient of the information.

  The same message also contains a brief item advising that adoption of this method was "recommended by CINCFE. [Commander in Chief Far East, or Mac-Arthur]." CINCFE also advised Washington that information including plans and theories of Ishii and his superiors could probably be obtained by granting written guarantees of immunity to Ishii and his associates. Moreover, Ishii could assist in securing the complete cooperation of his former subordinates. All of these ideas suggest that MacArthur strongly supported the idea of determining war crime liability in light of what potential defendants could offer in exchange for amnesty.

  It is interesting that in almost all communications between SCAP and Washington concerning these matters, the term "war crimes," with or without capital letters, is enclosed in quotation marks. Critics have said from the day of its inception that the military tribunal was a court of the victors' judging the vanquished, rather than an objective judgment of war crimes. Considering the selectivity with which subjects were chosen for or excluded from trial, the U.S. military's casual treatment of this term suggests that there is more truth to this accusation than many people are willing to acknowledge.

  New information also whetted the Americans' appetites for additional data—and spurred them on to try to outmaneuver the Soviets. Actual copies of the Soviet interrogations of Japanese officers who were captured from Ishii's unit in Manchuria were handed over to the American military. MacArthur's headquarters advised the War Department that preliminary investigations "confirm authenticity of USSR interrogations and indicate Japanese activity in (a) Human experimentation, (b) Field trials against Chinese, (c) Large scale program, (d) Research on BW by crop destruction, (e) Possible that Japanese General Staff knew and authorized program, (f) Thought and research devoted to strategic and tactical use of BW . . . [A]bove topics are of great intelligence value to US. Dr. Fell, War Department representative, states that this new evidence was not known by US."

  Japanese researchers' experiments with crop destruction attracted particular attention. A list of questions drawn up by the Chemical Corps of the War Department for Dr. Fell to pursue included: "What we
re the main crops considered for destruction?"; "What field trials were carried out?"; "What kind of equipment had been developed for applying crop destroying materials?"; "What crop diseases do you know or can [you] recognize?"; and "Do any of these [known/recognized diseases] cause serious losses in the vicinity of the BW installation?"

  On June 3, 1947, the War Department in Washington communicated with Alva C. Carpenter of the Legal Section of SCAP, asking for detailed information on all possible war crimes evidence or charges against Ishii or any of his group "for consideration in conference here concerning this matter. Specifically what evidence of war crimes is now in possession of the U.S. authorities against Ishii or any member of the group for whom he has requested immunity." Vigilant against threats to its monopoly on the treasure trove of biological warfare knowledge at hand, the War Department also wanted to know which American allies had filed war crimes charges against Ishii or his associates.

  Carpenter replied that his section had only anonymous letters, affidavits of hearsay, and rumors on Ishii and his associates. He informed Washington that "the Legal Section interrogations to date of the numerous persons concerned with the BW project in China, do not reveal sufficient evidence to support war crime charges. The alleged victims are of unknown identity. Unconfirmed allegations are to the effect that criminals, farmers, women and children were used for BW experimental purposes." Legal Section noted allegations by the Japanese Communist Party that Ishii and his group "conducted experimentation on captured Americans in Mukden and that simultaneously, research on similar lines was conducted in Tokyo and Kyoto."