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Japan: CBW

Shamshad Ahmed Khan was Research Assistant at the Institute for Defence Studies and Analyses, New Delhi. Click here to for detailed profile
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  • October-December 2009
    Country Profile

    Japan claims that it does not possess Weapon of Mass Destructions including the Chemical and Biological Weapons. Determined never to revisit war following its disastrous defeat in World War II, it has enshrined renunciation of war, non-possession of war potential and denial of belligerency of state1 in its Constitution promulgated in 1947 as its stated policy in this regard. Various policy documents including Japan’s defense white paper interpret the nonpossession of war potential as “possession of those (war potentials) that are characterized as offensive weapons that by the nature of their performance are intended to be used only for the mass destruction for another country,…under no circumstances are these weapons permissible”2.

    However, its own history of Chemical and Biological weapon is tainted as it pursued covert Chemical Warfare programmes during its colonial expansion and set up various laboratories in mainland China including the infamous “Unit 731” and experimented on prisoners to test its effect in battlefield. Japan had been in the state of denial over its covert programmes and it had not allowed the issue to be included in the Japanese text books arguing that “no credible scholarly research, articles or book, have yet been published on this issue, it is premature to discuss it in a textbook”3

    The issue of Japanese Chemical Warfare remained uncovered till some of the records of Khabarovsk war trial held in USSR in 1949 were made public. The records of interrogation of 10 Japanese Prisoner of Wars (POWs) captured during the World War II revealed that the Japanese Chemical and Biological Warfare was largely the responsibility of two detachments of Japanese Kwantung Army established in 1930s in Northeast China. Colonel Shiro Ishii, a Japanese medical officer who established a biological warfare research centre in 1935 in Japanese occupied Manchuria is considered the main architect of Unit 731.4

    Another detachment, Unit 100, was under the commandment of Jiro Wakamatsu and the task of the unit was limited to devising and producing bacteriological weapons of sabotage in the form of exterminating animals and contaminating crops.5

    The Japanese used flea as a main vector and the main agents as was revealed by Japanese POWs at Khabrovsk trial were plague, cholera, typhoid and anthrax and the methods of dissemination they discussed were spraying from aircraft, bombing and direct contamination of water and land. Various out breaks of plague and typhoid were attributed to Biological Warfare attacks.6

    The issue of Japanese colonial chemical and biological warfare could not become a matter of academic as well as public discourse until an investigative documentary “Unit 731: Did Emperor Hirohito Know?” was released in 1985, which depicted the story of Colonel Shiro Ishi’s code named Unit 731. The documentary by British journalists portrayed that Unit 731, in Harbin, Manchuria had grown into an enormous installation with laboratory and germ production facilities, testing grounds, an airport and especially equipped germ dropping planes.7 The issue remained hidden from the public debate for over four decades also because the American investigators who conducted their own trial during occupation of Japan “were prevented by some of their own compatriots from uncovering the full story”8, as General Douglas MacArthur, Supreme Commander of Allied Powers, has struck a deal with Ishii in exchange for information.9 While British journalists who made documentary termed Ishii’s programme “the secrets of secrets”, historian Sheldon Harris demonstrated in his book, Factories of death: Japanese Biological warfare 1932-1945 and the American cover up, that it was known to, and collaborated in by, various elements of Japanese society. Sheldon offered circumstantial evidence of the Showa emperor having sanctioned biological warfare developments.10

    It is difficult to ascertain the after affects of usage of Japanese chemical and biological warfare in China, however as per a Chinese account, “during Japan’s invasion of China Biological Warfare activities were carried out in more than twenty provinces and cities, causing more than 200,000 casualties among the Chinese people”.11

    Since the accounts of journalists and historians were not corroborated with enough facts and records, the story they revealed remained shrouded with the mysteries. The cloud over the mystery of Japanese chemical and biological warfare started clearing when some of those involved in the Chemical and Biological Warfare confessed to their inhuman acts before media. One of the Japanese vivisectionists, Ken Yuasa, involved in Chemical Warfare in Changzhi (then Luan) in China’s Shanxi Province told the Japan Times that at least 1,000 people, including surgeons, nurses and servicemen were part of similar atrocities all over mainland China. About his experience on performing vivisection on live Chinese prisoners he told “I was afraid during my first vivisection, but the second time around it was much easier and the third time I was willing to do it.” Asked why he concealed this fact for so long, he revealed that “I was in denial of the things I did in Luan until the war was over. It was because I had no sense of remorse while I was doing it. It is difficult for anyone, including myself to admit having done something evil. “12

    Japan also has the unfortunate distinction of being the target for chemical terrorism involving nerve agent Sarine. In 1994-95 Aum Shinrikyo, a new age cult, used improvised Chemical Warfare agents in Tokyo Metro trains killing about 14 people and affecting more than 5000.

    It was the Tokyo subway incident that led Japan to think that “the development and use of chemical weapon by non-State actors are palpable threats to international peace and security.” Its ratification of Chemical Weapon Convention (CWC), a convention that supplants 1925 Geneva Protocol, coincides with incident of Sarine gas attack in Tokyo subway. The CWC bans the acquisition, development, production, stockpiling, transfer and use of chemical weapons.

    After ratifying the Convention of Biological Weapons in 1982 and Chemical Weapon Convention (CWC) in 1997, Japan has been aggressive campaigner to eliminate weapon of mass destruction including nuclear, biological and chemical weapons. It has utilized its diplomatic tools for the universalization of the two conventions which supplant 1925 Geneva Convention.

    In compliance to its obligation under the CWC and Organization for the Prohibition of Chemical Weapons (OPCW) it has declared its 588 industry plant site where it undertakes Chemical and biological research for purposes other than Chemical weapons and has allowed inspection of these industrial sites. It is pushing the OPCW to improve the industry verification regime and has been pursuing the State Parties and technical Secretariat to make the CWC’s multilateral disarmament convention a success13.

    However, it is still struggling at the international level to correct its historical past in China. In accordance to the CWC it has signed Memorandum of Understanding with China to excavate abandoned Chemical Weapons and destroy them. So far Japan and China have conducted more than 120 bilateral investigation and excavation and have recovered more than 40,000 abandoned Chemical weapons14. But it is yet to begin substantive destruction of these abandoned Chemical Weapons.


    • 1. Article 9 of the Japanese Constitution states: Aspiring sincerely to an international peace based on justice and order, the Japanese people forever renounce war as a sovereign right of the nation, or the threat or use of force, as a means of settling disputes with other nations. In order to achieve the purpose of the preceding paragraph, the land, sea and air forces, as well as other war potential, will never be maintained. The right of belligerency of the state would never be recognized.
    • 2. Defense of Japan 2004, (Japan’s Defense Whitepaper) p.113
    • 3. For details read Saburo Ienaga, “The Glorification of War in Japanese Education”, International Security, Vol.18, No.3, (winter 1993/94) pp.113-133. The author writes that he had to delete the references to Unit 731, from the manuscript of school text book following the objections from Japan’s Ministry of Education which screens the text books before approving it for publication.
    • 4. Cookson, John and Nottingham, Judith, (1969) “A Survey of Chemical and Biological Warfare”, Sheed and Ward Ltd, (London). pp 56
    • 5. Ibid, pp 56
    • 6. Ibid, pp 56 and 296
    • 7. Unit 731: Did Emperor Hirohito Know?, A TVS Production, London 1985, review by John W. Powell, in The Journal of Asian Studies, Vol. 51, No.1 ( February 1992), pp. 225-227.
    • 8. Williams, Peter and Wallace, David (1989), Unit 731: Japan’s Secret Biological Warfare in World War II, Free Press, New York. pp. 229.
    • 9. Historian Stephen C Mercado supporting the fact writes: Many Japanese biological warfare specialists were granted immunity from prosecution in exchange for their Biological Warfare data and equipment removed from the death factories on the Asian continent to Japan in August 1945. For detail read ,Stephen C Mercado (2002), The Shadow Warriors of Nakano: A History of the Imperial Japanese Army’s Elite’s Intelligence School, Dulles, Virginia , : Brassey’s Inc pp 165-199.
    • 10. Sheldon H. Harris (1994), Factories of Death : Japanese Biological Warfare 1932- 45 and the American Cover-up. London and New York: Routledge, p 144.
    • 11. Liu Huaqui, (2000) ed., Arms Control and Disarmament Book, National Defense Industry Press, Beijing. p. 368.
    • 12. Witness to War : Vivisectionist recalls his day of reckoning, The Japan Times, October 24, 2007.
    • 13. http://www.mfa.gov.cn/eng/wjb/zzjg/ jks/kjlc/shwq/t532424.htm (accessed on November 13, 2009)