During World War II, behind the Manhattan Campaign, which dropped atomic bombs on Hiroshima and Nagasaki in Japan, the United States had already formulated an Olympic campaign plan: if Japan did not surrender and continued to resist stubbornly, in mid-October 1945, the United States would drop 5,400 poison gas bombs in the northeast of Tokyo, Japan, and 110,000 tons of poison gas bombs would be dropped in 33 places throughout Kyushu, Japan on October 29. At that time, the whole of Japan will be filled with mustard gas, phosgene, and other poisonous gases.

At the beginning of 1945, the world anti-fascist war had entered its final stage, Germany was about to fall, but Japan was still in the final throes. Therefore, the United States began to step up the drawing up of a plan for landing operations against Japan.

In April 1945, the U.S. military had basically completed the final revision of the Japanese landing operation plan. The battle plan was called "Operation Olympic".

According to the plan, on November 1, 1945, the US Army's 40th Infantry Division and the 158th Regiment combat team will land on a small island off the west coast of Kyushu, and then the offensive forces of the US Army's nine divisions will start landing at three landing sites in Kyushu and go straight to Tokyo.

In conjunction with this operation, the U.S. 3rd Fleet was responsible for dealing with transport, aircraft, and airfields between Honshu, Shikoku, and Kyushu. Also participating in the war off the coast of Kyushu in Japan were the US 5th Fleet and the 7th Fleet, plus two aircraft carrier groups, the British aircraft carrier force, the anti-submarine group, and the logistics group, as well as amphibious landing ships, minesweepers, and support ships.

The U.S. Air Force was to bomb railroads and roads with bombers and fighters to cut off Japanese reinforcements.

In this operation, the United States will use 1,371 transports, cargo ships, and landing ships to transport 680,000 officers and men and more than 60,000 tanks to the shores of Japan. It is estimated that the number of people to be dealt with by the US military will reach at least 250,000 and as many as 1 million in the entire Olympic operation. To this end, on June 9, 1945, the head of the Chemical Warfare Logistics Department (CWS) of the U.S. Army Headquarters, which is responsible for the development and production, experiment, and training of biological and chemical weapons, submitted a report to the Chief of Chemical Warfare Logistics entitled "Feasibility Study on the Use of Poison Gas in the Olympic Campaign." This is a report on the study of Japanese urban targets suitable for the US military to use poison gas.

"Within 10 square miles (25.9 square kilometers) south and west of Tokyo, there are at least 50 urban industrial targets suitable for poison gassing," the report said. Of these, 25 are particularly suitable for gas warfare. It is estimated that a gas attack on these 25 urban streets within 250 square miles of scale and intensity could easily annihilate 5 million enemy people and injure more than 5 million people. ”

The report also lists 25 Japanese cities suitable for U.S. gas warfare, including Tokyo, Osaka, Nagoya, Kobe, Yawata (including Wakamatsu and Toda Kokura), Yokohama, Kawasaki, Hiroshima, Fukuoka, Nagasaki, Yokosuka, Amagasaki, Omuta, Sasebo, Niigata, Moji, Kyoto, Toyohashi, Shimonoseki, Wakayama, Kai, Gifu, Okayama, and Shizuoka.

In the following, this article focuses on the materials of the National Archives of the United States, the Aberdeen Experimental Field Historical Library, and the Roosevelt Library, and discloses the full story of the U.S. poison gas war program against Japan with reference to U.S. research.

From sanctions to preemptive strikes

The US military has long had a plan to carry out poison gas warfare against the Japanese army, and has already begun to make preparations. U.S. President Franklin D. Roosevelt twice issued warning statements to Japan about gas warfare.

The United States has confirmed that the invading Japanese army used the lethal erosive gases mustard gas (the poison gas used by Germany in World War I) and Lewis gas on a considerable scale in Yichang, China, in October 1941, and has intercepted information that the Japanese army will continue to use poison gas in Yichang after it is released.

On June 5, 1942, U.S. President Franklin D. Roosevelt first issued a warning to the Japanese government: "If Japan continues to use this inhumane means of warfare against China or other United Nations members, my government will conclude that similar actions will be taken against the United States, and we may impose maximum sanctions on Japan in the same way." ”

On June 8, 1943, President Roosevelt warned for the second time: "Whatever poison gas the Axis uses may immediately provoke retaliation by the Allies to the maximum possible extent possible against the ammunition centers, seaports, and other military targets of the Axis throughout the Axis." ”

These two warnings are tantamount to an official statement that the United States will not be the first to use poison gas, but if Japan and other countries use poison gas, the United States will carry out maximum strikes against their military targets.

Soon, echoing the statements of US President Franklin D. Roosevelt, legends began to circulate among the US military that the United States was going to use poison gas. It was CWS Chief Porta who first submitted a submission to Lieutenant General McEnany at Army Headquarters on December 17, 1943. In this submission, Porta made two claims.

One proposition is that "the Japanese armed forces have repeatedly used poison gas against China, and we cannot give up the right to impose sanctions on Japan, and the initiative lies with the United Nations, which should immediately decide to carry out poison gas warfare against Japan."

Porta collected intelligence intercepted by the CWS, citing more than a dozen examples of the use of poison gas by Japanese forces in China and elsewhere after 1937. Two of these cases are the use of erosive poison gas by the invading Japanese army in Yichang, China, in 1941, and in 1942, it was also dispersed in the Taihang Mountains in Shanxi, China. In both cases, the poison gases were fatally detected in Japan.

The Japanese also released vomit gas in many other areas known as "red" (indicating danger). Typical examples are the use of cyanic acid gas on Guadalcanal Island in the Pacific Ocean in January 1943 and cyanic acid bombs on the south bank of the Yellow River in China's Shanxi Province in April of the same year.

The poison gas on Guadalcanal was used by a separate Japanese cell on a very small scale and there were no casualties, and both Naval Fleet Commander Kings and Army Chief of Staff Marshall reiterated that the United States would not use this as a justification for American retaliation. However, the poison gas used on the south bank of the Yellow River in China's Shanxi province has not been confirmed by the US military.

The report also cited more than a dozen examples of poison gas used by Japanese soldiers based on news and communications information from November 4 to December 13, 1943, and argued that the United States had the right to retaliate against Japan and to impose sanctions on Japan.

Another claim made in Porta's report was to save the lives of American soldiers. He pointed out that in November 1943, in the landing of Pedio on Dalai Island in Kiribati, although the US military dropped 3,000 tons of high-performance bombs, the landing battle still could not be easily successful, and the fighting lasted only four days, and the US army suffered nearly 4,000 casualties. If, in the same place where the Japanese were stubbornly resisting, the U.S. forces could have taken the island unscathed by dropping 900 tons of mustard gas bombs, Porta said.

At the time, Porta concluded in his report that "if used properly, poison gas could end the war in the Pacific as soon as possible and prevent more American soldiers from losing their lives." ”

He pointed out that due to the use of poison gas by the Japanese army in China and Asia and the increase in US casualties, public opinion in the United States demanded that the US military use poison gas against the Japanese army. He asserted: "Because the Japanese army continues to use poison gas, because of the great sacrifices of the American army and the stimulation of the brutality of the Japanese army, because of the pressure of public opinion, it may be a matter of time before poison gas warfare is waged in the Pacific." ”

Therefore, Porta's opinion clearly stated that the gas war was conducted in order to sanction Japan for its use of poison gas in China and Asia, and also to reduce the number of casualties among the US troops. Moreover, the opinion paper proposed that in order to reduce the number of casualties of the US military, the United States must preemptively use poison gas.

There is no moral objection

After discussion by the staff of the Operations Department of the Army Headquarters, the staff of this opinion held that it was too early to use poison gas. On December 27, 1943, the Chief of Staff, Major General T. Handy, summed up the opinion of the War Department as follows: Once the gas war has begun, it cannot be controlled. The use of poison gas against Japan may induce the large-scale use of poison gas by Germany, which will pose a threat to the landing campaign on the European continent carried out by the Allies, because the use of poison gas by the defenders will be a very effective means of defense. Therefore, Germany could not be given an excuse to use poison gas.

The United States can use poison gas because American citizens are rarely at risk of retaliation, but this is not the case in the Allied Powers, namely the United Kingdom, Australia, the former Soviet Union, and China. At the same time, preparations for a large-scale gas war in the Pacific Ocean will create problems on the military station, such as the maintenance of a large number of troops and a large number of transport ships, as well as chemical warfare ammunition.

Therefore, the reason that "it is too early to use poison gas" is only a strategic reason. What is remarkable is that because the invading Japanese army used poison gas and bacteria in China and the German army used poison gas to massacre Jews on a large scale, when the US military put forward this report on the implementation of poison gas warfare, no one objected to the idea that "fighting poison gas warfare is morally inhumane."

Soon, the argument that it was not strategically appropriate for the time being to use poison gas was about to disappear with the imminent surrender of Germany.

However, at this time, two actions taken by the Japanese government in early 1944 unexpectedly prompted the US military to decide to carry out a devastating blow against Japan, formally carry out the formulation of the Olympic battle plan and preparations for the gas war against Japan, and set the number of the gas war against Japan, that is, the Olympic campaign plan, as "JCS825".

The Government of Japan, through the International Committee of the Red Cross, conveyed to the United States its concerns about the public opinion that the United States was preparing to use poison gas against Japan, and at the same time, the Japanese envoy met with the King of Rome and asked him to convey to the United States Japan's commitment not to use poison gas and to receive a clear answer from the United States.

The Japanese envoy's pledge also included that "the Japanese army will never use poison gas in China," and the US General Staff Headquarters had confirmed through intelligence that this promise was extremely dishonest, so it reissued US President Rofos's statement and concluded in April that there was no need to make too many statements.

Immediately afterwards, the US military discovered that the preparations for inflicting a heavy blow on Japan, as outlined in the US President's statement, were not sufficient, so Army Air Force Commander Arnold submitted this as a memorandum to the US General Staff Headquarters in June, and preparations for a poison gas war against Japan were quickened.

Equipped with 110,000 tons of poison gas bombs

In August 1944, the United States decided to set January 1, 1945, as the date for the end of preparations for a retaliatory gas war against Japan.

However, by 1945, if the U.S. military could not reach a position where it could launch a strategic poison gas attack on the Japanese mainland, that is, if it used poison gas strategically in China and the Philippines, the citizens of the Allied countries would suffer even more serious disasters. Therefore, the US military decided to revisit the combat scheme of gas warfare.

In October 1944, after further discussions, the US General Staff Headquarters finally decided that the date for the completion of preparations for a strategic poison gas war against the Japanese mainland, including the Okinawa Islands and Ogasawara Islands, would be set for April 1, 1945, and the date for the completion of preparations for a strategic poison gas war against Japanese forces in Asia and the Pacific region would be set for January 1, 1945.

At the same time, the US General Staff Headquarters also drew up an outline of the operational plan, with B-29 and B-25 planes dropping poison gas bombs as the main part of strategic bombing, and the most concentrated bombing was carried out in the first 15 days, dropping 23,340 tons of 1,000-pound non-persistent gas bombs (asphyxiating phosgene, etc.), 6,280 tons of 500-pound non-persistent gas bombs, and 23,280 tons of 100-pound persistent gas bombs (mustard gas, etc.) in the first one month.

In order to ensure that orders reach the commanders of the US Army in the Pacific Theater and to enable the US forces to carry out gas warfare immediately after the end of preparations for the gas war, a decision was made in the annex of 14 December to this combat plan to deploy the gas bombs to the commanders at the front. However, due to the delay in various preparations, especially the all-out efforts to surrender Germany and the emergency transportation of troops, on March 5, 1945, the U.S. Military General Staff Headquarters instructed that the date of the end of preparations for gas warfare be reopened.

By April 1945, the Olympic battle plan had been basically formulated. The German fascists surrendered on May 7, 1945. Therefore, the General Staff Headquarters of the US Army, after confirmation, once again confirmed the policy of "setting the date for the end of the preparatory work to be November 1, 1945, and producing enough poison gas bombs to carry out retaliatory gas warfare at any time from that date."

According to this policy, it was stipulated that 113,500 tons of poison gas bombs could be deployed in the Pacific-China theater of operations for the Japanese landing in Kyushu, known as the "Olympic Campaign," which began on November 1, 1945, before the end of preparations for the gas war.

A poison gas attack was carried out before the landing in Kyushu

When formulating this policy, the US General Staff Headquarters adopted the form of sanctions in accordance with the spirit of US President Roosevelt's statement, that is, if Japan still stubbornly persists in using poison gas during this period, it will impose poison gas sanctions on Japan. Preparations for the US gas war have officially begun.

However, as mentioned above, Japan has indirectly indicated to the United States that it will not be the first to use poison gas bombs. According to the analysis of the sixth part of the "Olympic Campaign Plan," Japan did not dare to rashly use poison gas bombs except for the last desperate gamble, and even at the last moment of the war, it is estimated that Japan would not dare to use poison gas bombs against the United States, even though they were already trapped in the fight.

Despite this, the intelligence intercepted by the U.S. military proved that the Japanese military in China and Southeast Asia had gone into a state of frenzy as a result of the demise of the German fascists, and began to destroy the poison gas and bacteriological equipment established there, massacred the prisoners there, and according to all indications, the Japanese army continued to release poison gas and bacteria in those areas. Therefore, preparations for the US military's poison gas warfare are still in full swing.

At this time, due to the preparations for the Olympic Campaign, the capacity of the military station had reached its limit, and the Planning Department of the US General Staff Headquarters naturally questioned whether it was worth doing so on the basis of the analysis of the sixth part of the "Olympic Campaign Plan" mentioned above.

However, at this time, the doubts of the Planning Department of the General Staff Headquarters were already insignificant, and the Army Headquarters was stepping up its research on the targets of the Olympic Campaign.

First of all, according to the plan of the War Department of the Army Headquarters, on the basis of the sixth part of the Olympic Campaign Plan, the 33 targets on the map were listed in the "Second Draft" of the Objective Study formulated on June 1, 1945, and the weaknesses of Japan's anti-poison facilities were pointed out, and the conclusion was that the strategic and tactical conduct of poison gas warfare in the Olympic Campaign was "effective" and "advantageous."

From three days before the start of the landing operation, the plan is to carry out mustard gas and phosgene attacks on Japanese ports, naval bases, major transportation routes (parking lots, railway repair factories, railway change stations), coasts where the landings are to be made, air bases, local military headquarters, supply factories, and weapons factories, and to carry out attacks mainly on the central areas of Saga, Fukuoka, Oita, Kumamoto, Moji, Matsuyama, Hiroshima, Kure, and other cities, and to pollute water supply facilities in Fukuoka and Yawata.

After receiving this plan, M· Senior Colonel J. Johnson recommended to General Lincoln that poison gas attacks on cities other than southern Kyushu and Toki, Tsushima, and Matsuyama should include the six major cities including Tokyo, and suggested that "in order to achieve a strategic breakthrough in the Olympic Campaign, poison gas should be used as much as possible to support operations."

He advocated that if a completely closed war of annihilation was adopted, even if it could not be used to make Japan collapse, it would be possible to induce Japan to surrender, but at this time, the US military must preemptively use poison gas.

Second, the objective study of the CWS (Chemical Warfare Logistics Department) introduced above is based on the fourth part of the Olympic Campaign Plan, and is based on various experiments on the use of poison gases conducted from 1943 to 1945 at the Doug Hoy Experimental Site in Utah, USA, and San Jose near Panama.

Bombing of Tokyo in mid-October

616 B-29 planes took off from Mariana (61,600 tons of gas bombs were dropped in one month), 232 B-29 planes took off from Okinawa (37,120 tons of gas bombs), and 216 B-24 planes (7,020 tons of gas bombs), and these strategic bombers alone were able to drop 105,740 tons of gas bombs in one month.

In addition, there are three Japanese cities that will be attacked, and the report also indicates specific areas of attack.

First of all, in densely populated Tokyo, the U.S. military set the start date of the attack at 6 a.m., 15 days before the start of the Olympic Campaign, with the aim of "strategically bombing urban areas with phosgene bombs and inflicting mass casualties." Phosgene was chosen because in the morning of mid-October, the effect of mustard gas wanes in the low temperature of Tokyo.

The target is 17.5 square miles (44.8 square kilometers) from the north of the Imperial Palace, due north to the area around Korakuen, Rokugien Garden, and Oji Station, due east to the Ryogokubashi area, and the 17.5 square miles (44.8 square kilometers) enclosed on the west bank of the Sumida River.

The amount of ammunition dropped was 5,420 t000-pound bombs dropped by the B-29 or 21,680 five-pound bombs, and the population of this area was 948,000, with an estimated population of 776,000 at 2 miles below the wind in the target area.

The second is the strategic use of mustard gas bombs against Hachiman (Toda). Targeting the 2.8-square-mile industrial and densely populated areas of Hachiman and 2.25 square miles of Toda, 18,764 100-pound bombs were scheduled to be dropped from 6 p.m. three days before the start of the Olympic campaign. The population of this area is 155,800 in Yawata and 123,400 in Toda.

In addition to Tokyo and Hachiman, 23 cities were attacked by Tokyo-type phosgene or Yawata-type mustard gas, and it is estimated that more than 5 million people will be killed in the entire campaign.

Thirdly, the tactical use of cyanide chloride against the Japanese Army barracks and army headquarters in Kagoshima City. The attack was scheduled to begin at 6 a.m. on the day of the start of the Olympic campaign, and 340 1,000-pound bombs and 702 500-pound bombs were dropped. This poison gas has the ability to penetrate the Japanese army's gas masks, and it is estimated that it can make the Japanese local army command unable to resist.

Reduce casualties and end the war as soon as possible

The report concluded that "if the first attack was to be carried out with poison gas within 15 days before the start of the Olympic Campaign, Japanese lives could be destroyed," and that because of the preemptive use of poison gas, "we would have been able to take the initiative in carrying out the largest sneak attack on the greatest scale."

As a result, the CWS report explicitly advocates the preemptive use of gas bombs.

If the objective of the final use of gas warfare in the Olympic campaign were to be formally decided, then the above objectives might be combined into a single plan.

Under pressure from the Army Headquarters, General Marshall, Chief of Staff of the Army, immediately took action to change the sanctioning nature of the gas warfare plan to a preemptive use of poison gas.

On May 25, 1945, General Marshall announced that in order to minimize the casualties of American troops in the Olympic Operation, he discussed with Army Commander Stimso the issue of dropping the atomic bomb, and discussed the tactical use of mustard gas and other poison gases on the islands far from the Japanese mainland as a new tactic, and concluded that "this tactic is no more inhumane than phosphorus and flame emitters."

On 14 June, he handed over the memorandum to Commander of the Naval Fleet, Kings, in which he made the following statement.

The total defeat of Japan is irreversible, and the question that remains is how long this war will last, and how much it will cost the United States to achieve a final victory, to reduce the casualties of American soldiers, to bring the war to an early end, and that poison gas is the only weapon that has not been used before, among the weapons that can effectively strike the other side. To use poison gas, the Olympic campaign, "militarily is the most ideal time."

General Marshall claimed that the United States' preemptive use of poison gas had been restrained, and that the United States had been bound by President Roosevelt's statement, the agreement with Britain through the US-British Joint Staff Headquarters, and the policy agreement between General Maia Haiti and President ****** in the Chinese theater.

He noted that the cost of the war in the Pacific, especially the lives of soldiers, occurred on the side of the United States, not the British. Therefore, he came to the following conclusion: "The General Staff Headquarters of the United States Army agreed to begin a full-scale poison gas war against Japan on the day of the launch of the Olympic Campaign, and asked the President for permission to do so." The General Staff Headquarters of the Military Department hoped to raise the issue at a meeting attended by the President, involving Prime Minister Churchill and Field Marshal Stalin, and later President ******. ”

The advancing Olympic campaign

In order to end the war as soon as possible and reduce the casualties of US soldiers, the US military advocated the preemptive use of poison gas while carrying out the Olympic operation.

According to a study by Frederick Brown, a graduate of Boston University, in a June 1945 poll of public opinion in the United States, 40 percent of Americans were in favor of using poison gas against Japan in order to reduce casualties among American soldiers, and 49 percent were opposed. General Marshall believed that such public opinion would be a very favorable inducement. The claim for preemptive use of poison gas was finally confirmed.

However, in response to the proposal, General Ray Hei, the speaker of the U.S. General Staff Headquarters, said on June 20 that there was no need to change former President Roosevelt's statement, while arguing that even those who advocated gas warfare agreed that it should be discussed with President Truman.

In response, on June 21, General Marshall tentatively acknowledged the condition for the use of sanctions, but advocated the deployment of gas bombs in the Mariana Islands and Okinawa Islands as "if we have the ability to carry out huge attacks mainly from aircraft [on the Japanese mainland], the demand for gas bombs may increase rapidly."

As a result, although the question of the use of poison gas bombs against Japan was not raised at the Potsdam table, preparations for the gas war for the supply of the Olympic campaign were still intensifying.

General Marshall declared on 6 July that the gas munitions used within 75 days of the start of the campaign were now ready for use, and that the arsenal was increasing production to last nine months at the predetermined maximum size of the attack. At the same time, on 13 August, before Japan's surrender, he decided that the possible amount of gas bombs to be used on 1 November should reach 117456 tons, and that preparations for non-persistent gas bombs should be very adequate.

In the case of persistent gas bombs, 100-pound bombs are not sufficient to be eliminated by incendiary bombs and general-purpose bombs of the same weight, so it is necessary to concentrate on the study and discuss the turnover of captured gas munitions, United Nations weapons repatriation, additional replenishment, etc.

The bomb shortage that accompanied the massive incendiary bomb attacks on Japanese cities would also have had a significant impact on poison gas attack plans, but General Marshall believed that it was a problem that could be overcome.

The atom bomb was later gassed

There are different opinions in the US Government on the question of how to deal a devastating blow to Japan's war arrogance and how to end the war as soon as possible, with some advocating that the former Soviet Union enter the war, which President Roosevelt had long proposed; Some believe that it is enough to blockade the sea and carry out strategic bombing with incendiary bombs and general-purpose bombs; There are also advocates of the use of the atomic bomb, that is, the implementation of the Manhattan Project; Others believe that it is necessary to conduct a landing operation on the Japanese mainland.

Some people also believe that the former Soviet Union's participation in the war played a decisive role in actually and effectively forcing the commanders of Japan's war of aggression to make up their minds to surrender, and that the dropping of atomic bombs and strategic bombing was of great significance in making the Japanese people dispel their will to fight, and that landing operations could be dispensed with.

In addition, the use of poison gas may incur Japan's retaliatory use of poison gas and bacteriology in various theaters in Asia and the Pacific, and the consent of Britain, the former Soviet Union, and China must be obtained. For the United States, this is a kind of restriction on the use of gas warfare.

From the capture of Okinawa in June 1945 to the Olympic Campaign in November, the U.S. military had not conducted a large-scale operation against Japan except for a naval blockade and strategic bombing. Therefore, the United States decided to use the atomic bomb first, and if Japan did not surrender, the actual combat of poison gas began with the Olympic campaign. However, before the gas could be used, Japan surrendered on August 15, 1945, shortly after the United States dropped two atomic bombs, and the war ended.

During this period, the reason why the United States could not wait to drop the atomic bomb on Japan on July 12, just after the first atomic bomb test was successful, was because the United States did not want people to think that the former Soviet Union's entry into the war was the direct cause of forcing Japan to surrender and end the war, and at the same time, the United States also had a strong intention to test the power of the atomic bomb in the form of actual combat before the end of the war. For U.S. leaders, the atomic bomb is an easier weapon to use than gas bombs, which are somewhat restrained.

What if the entry of the former Soviet Union into the war was delayed, and the development of the atomic bomb by the United States was delayed? At that time, the Olympic campaign may be carried out, and the United States is very likely to carry out full-scale poison gas warfare in order to reduce the casualties of American soldiers.

If the Soviet Union's entry into the war had been postponed and the United States had already dropped atomic bombs on Japan, but the Japanese militarists continued to resist, then the United States had already used the atomic bomb, a top-of-the-line weapon, and it would be impossible to hesitate to use poison gas.

If the development of the atomic bomb is delayed and the former Soviet Union enters the war, Japan will most likely surrender immediately, and the United States will not have the opportunity to use poison gas again. However, the fact that Japan surrendered as a result of the Soviet Union's entry into the war greatly exaggerated the role of the former Soviet Union in Asia, which the United States did not want to see, so the United States may have hastily used poison gas before the former Soviet Union entered the war.

Barton Bansta, a professor at Stanford University in the United States who studied the biological warfare program against Japan, speculated that if the war continued until mid-August, the United States might have carried out bacteriological warfare and dead leaf warfare against Japan, because President Truman was said to have later recalled that the atomic bomb was a worse weapon.

As we all know, this dead leaf war was the plan of the United States to dry up 30% of Japan's rice in the "Corolla" campaign (Japan's Kwantung landing operation) that the United States prepared to carry out in 1946. In that case, it can be said that the gas warfare that is being prepared in reality is more direct and more likely to be implemented than this plan.

Conclusion

The United States formulated its plan to wage poison gas warfare against Japan, first of all, because Japan had used poison gas and bacteriology frequently and continuously against the Asian region, especially against China, since 1937, which had provoked the United States to prepare sanctioned attacks and even preemptive attacks. In June 1942, after the U.S. President's warning statement, the Japanese military continued to use poison gas and germs in China. U.S. military intelligence had reached President Roosevelt, proving that on June 23, 1944, Japanese troops were also using mustard and Lewis gas on the outskirts of Hengyang, China. Moreover, the Japanese army continued to use vomit gas in China until June 1944 and never stopped.

Second, looking at the US Olympic campaign plan, it is not difficult to see that the public opinion, preparations, and conditions for sanctioning the use of poison gas at the beginning have all been quite mature, and at the same time, they are changing to the preemptive use of poison gas. Moreover, the real purpose of the US military's use of poison gas is to end the war as soon as possible and reduce the casualties of US soldiers.

This is also a valid reason for the United States to use the atomic bomb. The hegemony of the United States that is not bound by international law that prohibits the use of poison gas, the bestiality of the Japanese fascists who started the war and have been using poison gas, the possibility of launching a poison gas war in Europe brought about by Germany's surrender has disappeared, and the terror that the United States itself will not be attacked by poison gas has all increased the temptation for the United States to use poison gas first.