Japan and weapons of mass destruction

Aspect of Japan's military history

Beginning in the mid 1930s, Japan conducted numerous attempts to acquire and develop weapons of mass destruction. The 1943 Battle of Changde saw Japanese use of both bioweapons and chemical weapons, and the Japanese conducted a serious, though futile, nuclear weapon program. Since World War II, the United States military based nuclear and chemical weapons and field tested biological anti crop weapons in Japan. Japan has since become a nuclear capable state, said to be a "screwdriver's turn" away from nuclear weapons; having the capacity, the know how, and the materials to make a nuclear bomb. Japan has consistently eschewed any desire to have nuclear weapons, and no mainstream Japanese party has ever advocated acquisition of nuclear weapons or any weapons of mass destruction. There are controversies on whether such weapons are forbidden by the Japanese constitution or not. Japan has signed many treaties prohibiting these kinds of weapons. Japan is the only nation that has been attacked with atomic weapons. Prior to 1946 Japan carried out many attacks using weapons of mass destruction (chemical and biological), principally in China. In 1995, members of the Japanese religious cult Aum Shinrikiyo released chemical weapons in Tokyo in a domestic terror attack.

The Japanese used mustard gas and the blister agent Lewisite against Chinese troops and guerillas in China, amongst others during the Changde chemical weapon attack. Experiments involving chemical weapons were conducted on live prisoners (Unit 516). As of 2005, sixty years after the end of the war, canisters that were abandoned by Japan in their hasty retreat are still being dug up in construction sites, causing injuries and allegedly even deaths. Several chemical attacks on various people using VX gas and sarin and the Tokyo subway sarin attack on the Tokyo subway on March 20, 1995, were perpetrated by members of the cult movement Aum Shinrikyo in acts of domestic terrorism. A large stockpile of other chemical agents and precursor chemicals were later found in raids on their facilities. In 1995, JGSDF admitted possession of sarin samples for defense purposes. Japan had signed the Chemical Weapons Convention in December 1993. Japan ratified The Chemical Weapons Convention in 1995 and was thus a state party upon it entering into force in 1997.

A Japanese program to develop nuclear weapons was conducted during World War II. Like the German nuclear weapons program, it suffered from an array of problems, and was ultimately unable to progress beyond the laboratory stage before the atomic bombings of Hiroshima and Nagasaki and the Japanese surrender in August 1945. The postwar Constitution forbids the establishment of offensive military forces, but not nuclear weapons explicitly. In 1967 it adopted the Three Non Nuclear Principles, ruling out the production, possession, or introduction of nuclear weapons. Japan signed the Treaty on the Non Proliferation of Nuclear Weapons in February 1970. While there are currently no known plans in Japan to produce nuclear weapons, it has been argued that Japan has the technology, raw materials, and the capital to produce nuclear weapons within one year if necessary, and some analysts consider it a de facto nuclear state for this reason. For this reason Japan is often said to be a "screwdriver's turn" away from possessing nuclear weapons. During the 2016 U. S. presidential election it was proposed by GOP candidates to allow both Japan and the Republic of Korea to develop nuclear weapons to counter a North Korean missile threat.

Solid fuel rockets are the design of choice for military applications as they can remain in storage for long periods, and then reliably launch at short notice. Lawmakers made national security arguments for keeping Japan's solid fuel rocket technology alive after ISAS was merged into the Japan Aerospace Exploration Agency, which also has the H IIA liquid fueled rocket, in 2003. The ISAS director of external affairs, Yasunori Matogawa, said, "It seems the hard line national security proponents in parliament are increasing their influence, and they aren't getting much criticism I think we’re moving into a very dangerous period. When you consider the current environment and the threat from North Korea, it’s scary." Toshiyuki Shikata, a government adviser and former lieutenant general, indicated that part of the rationale for the fifth M V Hayabusa mission was that the reentry and landing of its return capsule demonstrated "that Japan's ballistic missile capability is credible." At a technical level the M V design could be weaponised quickly (as an Intercontinental ballistic missile) although this would be politically unlikely. In response to the perceived threat from North Korean launched ballistic missiles, Japanese government officials have proposed developing a first strike capability for Japan's military that includes ballistic and cruise missiles.

The threat of North Korea based ballistic missiles that are within range of Japan have guided Japanese and U. S. defense and deterrence strategies.

In 1939, the U. S. State Department reported that a Japanese Army physician in New York City had attempted to obtain a Yellow fever virus sample from the Rockefeller Institute for Medical Research. The incident contributed to a sense of urgency in the United States to research a BW capability. By 1942 George W. Merck, president of Merck and Company, was made chairman of the War Research Service which was established to oversee the U. S. development of BW related technology at Camp Detrick. After World War II ended, a U. S. War Departments report notes that "in addition to the results of human experimentation much data is available from the Japanese experiments on animals and food crops". The technical information of Japan's BW program participants was transferred into U. S. intelligence agencies and BW programs in exchange for immunity for war crimes charges. Sheldon H. Harris in Factories of Death: Japanese Biological Warfare, 1932–1945, and the American Cover Up wrote:blockquote|This was at least one year prior to the creation of Project 112. The Okinawa anti crop research project may lend some insight to the larger projects Project 112 sponsored. BW experts in Okinawa and "at several sites in the Midwest and South" conducted in 1961 "field tests" for wheat rust and rice blast disease. These tests met with "partial success" in the gathering of data, and led, therefore, to a significant increase in research dollars in fiscal year 1962 to conduct additional research in these areas. The money was devoted largely to developing "technical advice on the conduct of defoliation and anti crop activities in Southeast Asia." At the close of World War Two, the U. S. planned to attack Japan's food supply with anti crop chemical agents and by July 1945 had stockpiled an amount of chemicals "sufficient to destroy one tenth of the rice crop of Japan." However, logistical problems would have reduced that estimate. "The Okinawa tests evidently were fruitful." The Smithsonian Institution and The National Academy of Sciences and National Research Council administered special research projects in the Pacific. The motivation for civilian research programs of this nature was questioned when it was learned that such international research was in fact funded by and provided to the U. S. Army as requirement related to the U. S. military's biological warfare research.

Operation Pop Eye / Motorpool / Intermediary Compatriot was a highly classified weather modification program in Southeast Asia during 1967 1972 that was developed from cloud seeding research conducted on Okinawa and other tropical locations. A report titled Rainmaking in SEASIA outlines use of silver iodide deployed by aircraft in a program that was developed in California at Naval Air Weapons Station China Lake. The technique was refined and tested in Okinawa, Guam, Philippines, Texas, and Florida in a hurricane study program called Project Stormfury. The chemical weather modification program was conducted from Thailand over Cambodia, Laos, and Vietnam. The program was allegedly sponsored by Secretary of State Henry Kissinger and the Central Intelligence Agency without the authorization of Secretary of Defense Melvin Laird. Laird had categorically denied to Congress that a program for modification of the weather existed. The program employed cloud seeding as a weapon which was used to induce rain and extend the East Asian Monsoon season in support of U. S. government strategic efforts related to the War in Southeast Asia. The use of a military weather control program was related to the destruction of enemy food crops. Whether the use of a weather modification program was directly related to any of the chemical and biological warfare programs is not documented. However, it is certain that some of the military herbicides in use in Vietnam required rainfall to be absorbed. In theory, any CBW program employing fungus spores or a mosquito vector would have also benefited from prolonged periods of rain. Rice blast sporulation on diseased leaves occurs when relative humidity approaches 100%. Laboratory measurements indicate sporulation increases with the length of time 100% relative humidity prevails. The Aedes aegypti mosquito lays eggs and requires standing water to reproduce. Approximately three days after it feeds on blood, the mosquito lays her eggs over a period of several days. The eggs are resistant to desiccation and can survive for periods of six or more months. When rain floods the eggs with water, the larvae hatch.

U. S. chemical weapons in Japan were deployed to Okinawa in the early 1950s. The Red Hat mission deployed additional chemical agents in three military operations code named YBA, YBB, and YBF. The operation deployed chemical agents to the 267th Chemical Platoon on Okinawa during the early 1960s under Project 112. The shipments, according to declassified documents, included sarin, VX, and mustard gas. By 1969, according to later newspaper reports, there was an estimated 1.9 million kg (1,900 metric tons) of VX stored on Okinawa. In 1969, over 20 servicemen (23 U. S. soldiers and one U. S. civilian, according to other reports) were exposed to low levels of the nerve agent sarin while sandblasting and repainting storage containers. An official U. S. film on the mission says that 'safety was the primary concern during the operation,' though Japanese resentment of U. S. military activities on Okinawa also complicated the situation. At the technical level, time pressures imposed to complete the mission, the heat, and water rationing problems also complicated the planning. The Army leased on Johnston. Phase I of the operation took place in January and moved 150 tons of distilled mustard agent. The arrived at Johnston Atoll with the first load of projectiles on January 13, 1971. Phase II completed cargo discharge to Johnston Atoll with five moves of the remaining 12,500 tons of munitions, in August and September 1971. Units operating under United States Army Ryukyu Islands (USARYIS) were 2nd Logistical Command and the 267th Chemical Company, the 5th and 196th Ordnance Detachments (EOD), and the 175th Ordnance Detachment. Originally, it was planned that the munitions be moved to Umatilla Chemical Depot but this never happened due to public opposition and political pressure. The Congress passed legislation on January 12, 1971 (PL 91 672) that prohibited the transfer of nerve agent, mustard agent, agent orange and other chemical munitions to all 50 U. S. states. In 1985 the U. S. Congress mandated that all chemical weapons stockpiled at Johnston Atoll, mostly mustard gas, Sarin, and VX gas, be destroyed. Prior to the beginning of destruction operations, Johnston Atoll held about 6.6 percent of the entire U. S. stockpile of chemical weapons. The Johnston Atoll Chemical Agent Disposal System (JACADS) was built to destroy all the chemical munitions stored on Johnston island. The first weapon disposal incineration operation took place on June 30, 1990. The last munitions were destroyed in 2000.

The intensity of the fighting and the high number of casualties during the Battle of Okinawa formed the basis of the casualty estimates projected for the invasion of Japan that led to the decision to launch the atomic bombing of Japan. Atomic bombs were deployed in order to avoid having “an[nother] Okinawa from one end of Japan to the other.”

The atomic age on Japan's southern islands began during the final weeks of the war when the U. S. Army Air Force launched two atomic attacks on Hiroshima and Nagasaki from bases on Tinian in the Marianas Islands. Bockscar, the B 29 that dropped the Fat Man nuclear weapon on Nagasaki, landed at Yontan Airfield on Okinawa on August 9, 1945. The U. S. military immediately began constructing a second B 29 base and a facility for atom bomb processing in Okinawa to be completed in September 1945 that would open more targets in mainland Japan.

Japanese naval warships captured by the U. S. after Japan's surrender in World War II, including the Nagato, were used as target ships and destroyed in 1946 in nuclear testing at Bikini Atoll during Operation Crossroads. The atomic testing was conducted in the Marshall Islands group that U. S. forces captured in early 1944 from the Japanese. The first hydrogen bomb detonation, known as Castle Bravo, contaminated Japanese fisherman on the Daigo Fukuryū Maru with nuclear fallout on March 4, 1954. The incident further rallied a powerful anti nuclear movement.

Article 9 of the Japanese Constitution, written by MacArthur immediately after the war, does not explicitly prohibit nuclear weapons. But when the U. S. military occupation of Japan ended in 1951, a new security treaty was signed that granted the United States rights to base its "land, sea, and air forces in and about Japan." The discussion took place during negotiations in 1959, and the agreement was made in 1960 by Aiichiro Fujiyama, then Japan's Foreign Minister. During the early parts of the Cold War the Bonin Islands including Chichi Jima, the Ryukyu Islands including Okinawa, and the Volcano Islands including Iwo Jima were retained under American control. The islands were among "thirteen separate locations in Japan that had nuclear weapons or components, or were earmarked to receive nuclear weapons in times of crisis or war." According to a former U. S. Air Force officer stationed on Iwo Jima, the island would have served as a recovery facility for bombers after they had dropped their bombs in the Soviet Union or China. War planners reasoned that bombers could return Iwo Jima, "where they would be refueled, reloaded, and readied to deliver a second salvo as an assumption was that the major U. S. Bases in Japan and the Pacific theater would be destroyed in a nuclear war." It was believed by war planners that a small base might evade destruction and be a safe harbor for surviving submarines to reload. Supplies to re equip submarines as well as Anti submarine weapons were stored within caves on Chichi Jima. The Johnson administration gradually realized that it would be forced to return Chichi Jima and Iwo Jima "to delay reversion of the more important Okinawa bases" however, President Johnson also wanted Japan's support for U. S. Military operations in Southeast Asia." The Bonin and Volcano islands were eventually returned to Japan in June 1968. News of accidents on the island usually did not reach much farther than the islands local news, protest groups, eyewitnesses and rumor mills. However, the incidents that were publicized garnered international opposition to chemical and nuclear weapons and set the stage for the 1971 Okinawa Reversion Agreement to officially ending the U. S. military occupation on Okinawa. 32 Mace Missiles were kept on constant nuclear alert in hardened hangars at four of the island's launch sites. The 280mm M65 Atomic Cannon nicknamed "Atomic Annie" and the projectiles it fired were also based here. At the time, nuclear storage locations existed at Kadena AFB in Chibana and the hardened MGM 13 MACE missile launch sites; Naha AFB, Henoko [Camp Henoko (Ordnance Ammunition Depot) at Camp Schwab], and the Nike Hercules units on Okinawa. In June or July 1959, a MIM 14 Nike Hercules anti aircraft missile was accidentally fired from the Nike site 8 battery at Naha Air Base on Okinawa which according to some witnesses, was complete with a nuclear warhead. A similar accidental launch of a Nike H missile had occurred on April 14, 1955, at the W 25 site in Davidsonville, Maryland, which is near the National Security Agency headquarters at Fort George G. Meade. On October 28, 1962, during the peak of Cuban Missile Crisis U. S. Strategic Forces were at Defense Condition Two or DEFCON 2. According to missile technicians who witnessed events, the four MACE B missile sites on Okinawa erroneously received coded launch orders to fire all of their 32 nuclear cruise missiles at the Soviets and their allies. Quick thinking by Capt. William Bassett who questioned whether the order was "the real thing, or the biggest screw up we will ever experience in our lifetime” delayed the orders to launch until the error was realized by the missile operations center. According to witness John Bordne, Capt. Bassett was the senior field officer commanding the missiles and was nearly forced to have a subordinate lieutenant who was intent on following the orders to launch his missiles shot by armed security guards. No U. S. Government record of this incident has ever been officially released. Former missileers have refuted Bordne's account. Next, on December 5, 1965, off of the coast of Okinawa, an A 4 Skyhawk attack aircraft rolled off of an elevator of the aircraft carrier USS Ticonderoga (CV 14) into 16,000 feet of water resulting in the loss of the pilot, the aircraft, and the B43 nuclear bomb it was carrying, all of which were too deep for recovery. Since the ship was traveling to Japan from duty in the Vietnam war zone, no public mention was made of the incident at the time and it would not come to light until 1981 when a Pentagon report revealed that a one megaton bomb had been lost. Japan then formally asked for details of the incident. Last, In September 1968, Japanese newspapers reported that radioactive Cobalt 60 had been detected contaminating portions of the Naha Port Facility, sickening three. The radioactive contamination was believed by scientists to have emanated from visiting U. S. nuclear submarines.

Finally, on November 19, 1968, a U. S. Air Force Strategic Air Command (SAC) B 52 Stratofortress (registration number 55 01030) with a full bomb load, broke up and caught fire after the plane aborted takeoff at Kadena Air Base, Okinawa while it was conducting an Operation Arc Light bombing mission to the Socialist Republic of Vietnam during the Vietnam War. [[File:B 52 55 0103 Crash site, Kadena, AFB. jpg|thumb|230px|left|B 52 #55 103 Crash site, Kadena, AFB, Okinawa, November 19, 1968 The depot held the Mark 28 nuclear bomb warheads used in the MGM 13 Mace cruise missile as well as warheads for nuclear tipped MGR 1 Honest John and MIM 14 Nike Hercules (Nike H) missiles. The crash led to demands to remove the B 52s from Okinawa and strengthened a push for the reversion from U. S. rule in Okinawa. Former Governor of Tokyo 1999–2012, Shintaro Ishihara was an advocate of Japan having nuclear weapons. On 29 March 2016, then U. S. President candidate Donald Trump suggested that Japan should develop its own nuclear weapons, claiming that it was becoming too expensive for the US to continue to protect Japan from countries such as China, North Korea, and Russia that already have their own nuclear weapons. On 27 February 2022, former prime minister Shinzo Abe proposed that Japan should consider a nuclear sharing arrangement with the US similar to NATO. Abe wants to stimulate necessary debate: "It is necessary to understand how the world’s security is maintained. We should not put a taboo on discussions about the reality we face."