While Tokyo unsuccessfully attempted to develop nuclear weapons during World War II, its experiences during that war as the only country to have been attacked using nuclear weapons precipitated a strong commitment to nonproliferation and disarmament. Japan is a party to all relevant multilateral nonproliferation treaties and regimes. Tokyo ratified the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) in 1976 and the Comprehensive Nuclear Test Ban Treaty (CTBT) in 1997. While Japan developed and employed both chemical and biological weapons prior to 1945, Tokyo is now a state party to both the Chemical Weapons Convention (CWC) and the Biological and Toxin Weapons Convention (BTWC). Japan is also a member of the Australia Group, the Nuclear Suppliers Group, the Missile Technology Control Regime (MTCR), and the Zangger Committee.

Nuclear

Japan's commitment to nuclear disarmament and nonproliferation and its support for the NPT have remained unchanged since it acceded to the treaty in 1976. Domestically, Japan's "Atomic Energy Basic Law" allows only peaceful nuclear activities, [1] and its "Three Non-Nuclear Principles" pledge that Japan will not possess, produce, or permit the introduction of nuclear weapons into the country. [2] Despite Japan's long-standing stance against nuclear weapons, the domestic debate occasionally re-opens. For example, there was an internal debate in the early 1970s about whether Japan should sign the NPT. Moreover, Japan's "nuclearization" debate resurfaces periodically in response to the regional security environment, and especially the North Korean threat. The Japanese public's deep aversion to nuclear weapons and Tokyo's strong commitment to international nonproliferation regimes make any move in this direction improbable. However, Japan increasingly relies on nuclear power for its electricity needs, and has a highly developed civilian nuclear sector.

With almost no indigenous energy sources, nuclear energy has accounted for over 30% of the country's total electricity production, and Japan planned to increase this to at least 40% in 2017, and 50% by 2030. [3] Before the Great East Japan Earthquake and Tsunami on 11 March 2011, Japan had 54 nuclear power reactors in operation across the country (the third largest number in the world, after the United States and France). [4] As of March 2012, due to safety reviews, only two of the 54 nuclear reactors are operating. And both operating reactors are scheduled to be shut down for safety inspections by the end of April, leaving Japan without a single nuclear reactor operating in May unless some are restarted. [5]

On 11 March 2011, a 9.0-magnitude earthquake and subsequent aftershocks and tsunami waves precipitated power failures at the six-reactor Fukushima Daiichi Nuclear Power Station—since that time, Japanese personnel have been attempting to manage escalating crises involving loss of coolant and possible partial core meltdowns in units 1, 2, and 3, and dangerously low levels of water in the spent-fuel ponds at units 3 and 4. [6] All three units experienced core meltdown. The accident was the first level 7 accident, as defined by the International Nuclear Event Scale (INES) standard, since Chernobyl. It is unclear how much radiation has been or will be released into the environment, and what effects the tragedy will have on Japan's policies. According to Japanese governmental officials, the emission of radioactive substances from Fukushima Daiichi is approximately 10% of the amount that had been detected at Chernobyl. [7] On 16 December 2011, the Japanese government announced that the three reactors that suffered meltdowns had officially reached cold shutdown. However, the nuclear crisis is far from over.[8] The Japanese government is currently reviewing its new Framework of Nuclear Energy Policy, which was suspended due to the March 2011 Fukushima accident. The new policy is scheduled to be issued by the end of August 2012. IAEA Director General Yukiya Amano has stated: "I believe one lesson is already clear: the current international emergency response framework needs to be reassessed. It was designed largely in the wake of the Chernobyl disaster in 1986, before the information revolution. It reflects the realities of the 1980s, not of the 21st century" [9]

Biological

Japan had an active biological warfare (BW) program prior to 1945. The focal point of the program was the now infamous Unit 731, based at a laboratory complex in northeastern China during the Japanese occupation. Unit 731 experimented on Chinese civilians and Allied prisoners of war with various biological agents, including plague, cholera, and hemorrhagic fever. Additionally, the Japanese military used biological weapons against China. Most of the data that the Japanese military accumulated during WWII was confiscated by the U.S. military. After World War II, the Japanese government abandoned its BW program. Japan signed the BTWC in 1972 and ratified it in 1982, and has actively supported negotiation of a protocol to strengthen the treaty's provisions. Since the 1995 Aum Shinrikyo sarin (chemical weapons) attack and failed attempt to disperse anthrax, Japan has increased its focus on bio-terrorism defenses. Although Japan has a growing biotechnology industry, it is still small in comparison with its chemical industry. As a member of the Australia Group, Japan's biotech industry is subject to a comprehensive set of export controls.

Chemical

Japanese scientists began developing a chemical warfare (CW) capability as early as 1917. The Japanese Army used chemical weapons after invading China in 1937, conducting an estimated 1,000 to 3,000 attacks. Japan reportedly produced five to seven million munitions containing agents such as phosgene, mustard, lewisite, hydrogen cyanide, and diphenyl cyanarsine. [10] Although Japanese forces used many of these munitions between 1937 and 1945, they abandoned a considerable amount of the munitions while retreating. After World War II, Japan pledged it would not produce chemical weapons and participated in the negotiation of the Chemical Weapons Convention (CWC), which Japan signed in 1993 and ratified in 1995. Japan's CWC obligations include responsibility for the disposal of its abandoned chemical weapons in China. To that end, the Japanese government established the Abandoned Chemical Weapons Office under the Prime Minister's Office (now the Cabinet Office) on 1 April 1999. Between 300,000 and 400,000 munitions remain in China's Jilin Province. [11] The deadline for completion of the clean-up was 2007, but Tokyo and Beijing requested a five-year extension from the Organization for the Prohibition of Chemical Weapons (OPCW). Japan's chemical industry is the world's third largest after the United States and China. [12] As a member of the Australia Group, Japan has developed comprehensive and well-enforced export controls on chemical weapons precursors and dual-use items. Since the 1995 Aum Shinrikyo sarin attack, Japanese spending on CW defense has increased.

Missile

Japan does not have a ballistic missiles development program, but its space program includes a number of technologies that could potentially be adapted to serve as long-range missiles. Japan lacks sophisticated command-and-control systems, as well as some guidance and warhead technology that would be necessary to develop operational missiles. Japan is a member of the Missile Technology Control Regime (MTCR) and was involved in drafting the Hague Code of Conduct Against Ballistic Missile Proliferation (HCOC). Japan is one of the most active partners with the United States in the field of missile defense. Tokyo has deployed a multi-layered missile defense system consisting of sea-based midcourse missile defense (the Aegis BMD system), and ground-based terminal-phase missile defense (Patriot Advanced Capabilities-3). The Democratic Party of Japan (DPJ) government that came to power in the August 2009 general election temporarily diminished its support for missile defense. Although Tokyo continued to deploy missile defense systems as planned under the Liberal Democratic Party (LDP) administrations, and completed deployment of PAC-3 in April 2010, in its defense spending guidelines for FY2010 the DPJ cabinet suspended new funds for any further PAC-3 deployments until at least April 2011. [13] However, due mainly to heightened tensions in the region, the new National Defense Program Guidelines published in December 2010 called for further deployment and improvement of Japan's missile defense systems in cooperation with the United States. [14] Additionally, Japan has become more interested in space activities mainly because of North Korea's ballistic missile launches and the accelerating development of China's space program. On 27 August 2008, the Basic Space Law entered into force, lifting the ban on the Japanese government's use of space for defense purposes. [15] Another significant development in furtherance of U.S.-Japan cooperation in missile defense systems was the Japanese government’s decision to relax the three principles on arms export on 27 December 2011. With this development, Japan can allow the United States to transfer a jointly developed missile defense system to third countries, provided such a transfer contributes to Japan’s national security and international peace and security. [16]

Sources:
[1] "Atomic Energy Basic Act," Nuclear Safety Commission of Japan Website, www.nsc.go.jp.
[2] "On the Three Non-Nuclear Principles," Japanese Ministry of Foreign Affairs, www.mofa.go.jp.
[3] "Nuclear Power in Japan," World Nuclear Association, www.world-nuclear.org.
[4] "Nuclear Power in Japan," World Nuclear Association, www.world-nuclear.org.
[5] Kiyoshi Takenaka, "Japan says possible all reactors shut this summer," Reuters, 1 March 2012, www.reuters.com.
[6] For more details and future updates on the situation at Fukushima, see "Japan in Focus: A Collection of the Bulletin's Coverage," Bulletin of the Atomic Scientists, retrieved from BAS website 21 March 2011, http://thebulletin.org.
[7] Frank N. von Hippel, "The Radiological and Psychological Consequences of the Fukushima Daiichi Accident," Bulletin of the Atomic Scientists, September/October 2011
[8] Justin McCurry, "Fukushima is in cold shutdown, says Japanese prime minister," The Guardian, 16 December 2011, gurdain.co.uk.  Justin McCurry in Tokyo.
[9] "IAEA Board Discusses Fukushima Nuclear Accident," International Atomic Energy Agency, 21 March 2011, www.iaea.org.
[10] Abandoned Chemical Weapons Office, wwwa.cao.go.jp.
[11] Abandoned Chemical Weapons Office, wwwa.cao.go.jp.
[12] "Chemical Industry of Japan 2010," www.nikkakyo.org.
[13] "Japan to Halt New Missile Defence Spending: Media," Space War, 15 December 2009, www.spacewar.com; and "Petoriotto PAC 3 no Haibi nit suite, [Deployment of PAC-3]" Japanese Ministry of Defense, 26 April 2010, in Japanese, www.mod.go.jp.
[14] Japanese Ministry of Defense, "Summary of National Defense Program Guidelines," FY2011, www.mod.go.jp.
[15] "Ban lifted on use of space for defense," The Daily Yomiuri, 29 August 2009.
[16] Masami Ito, "Government goes ahead with easing arms export ban," The Japan Times, 28 December 2011, www.japantimes.co.jp.