As World War II drew to a close, and the grim realities of a potentially lengthy invasion of Japan loomed, there was a darker facet to Japan’s war strategy that went almost entirely unnoticed. This clandestine plan, code-named Operation PX, or “Cherry Blossoms at Night,” was a plan of terrifying scope and ambition: a biological attack on the United States’ mainland. Had it been successfully executed, the operation could have changed the trajectory of the war, resulting in catastrophic human loss.
The operation aimed to weaponize the bubonic plague, a bacteria known for its lethal power throughout history, and spread it within populous U.S. cities. The Japanese army intended to conduct the attack via specially-equipped submarines, some of which would launch aircraft carrying the deadly plague. The remaining would carry infected crews who would land on American shores and disseminate the disease.
While Japan never implemented Operation PX, the meticulous planning and sheer audacity of the plot have attracted historical scrutiny over the decades. Unveiled only in the late 20th century, the planned operation is a sobering reminder of the extreme lengths nations were willing to go to during World War II. Let’s delve deeper into this fascinating, albeit chilling, part of the war’s history.
Background of Operation PX
The origins of Operation PX can be traced back to Japan’s covert research into biological weapons during the early years of World War II. This research was carried out under the umbrella of a secret unit known as Unit 731. Established by Lieutenant General Shiro Ishii in 1936, this unit was responsible for some of the most horrific war crimes perpetrated by the Japanese Empire during the war.
Unit 731 was based in occupied Manchuria, away from prying eyes, where they conducted extensive experiments on live human subjects. Bubonic plague, anthrax, cholera, and a host of other biological agents were tested in a chilling series of trials designed to determine their effectiveness as weapons. Chinese civilians and prisoners of war were often the unfortunate test subjects.
In a terrifying series of field experiments, the unit would infect fleas with the bubonic plague. These fleas were then dropped from aircraft over populated areas in China, causing outbreaks of the deadly disease. The success of these tests became the cornerstone for developing Operation PX.
Unit 731’s operations were kept secret. Even amongst the Japanese military hierarchy, knowledge of the unit’s activities was limited to a select few. The gruesome experiments and tests were conducted under the guise of water purification and epidemic prevention services.
Planning Operation PX
With the successful testing of biological weapons, the Japanese military began planning Operation PX in earnest. They aimed to weaponize the bubonic plague and use it to instigate a pandemic on American soil, thereby destabilizing the U.S. war effort.
The plan was to deploy long-range submarines, the I-400 class, capable of carrying three Aichi M6A Seiran aircraft each. The aircraft were to be loaded with plague-infected fleas and flown over strategic U.S. locations, releasing their deadly cargo. This would result in the rapid spread of the disease, causing panic and chaos.
Furthermore, the submarines were to carry infected Japanese personnel who would land on U.S. soil. These soldiers, acting as human bio-weapons, would further disseminate the plague, accelerating the outbreak.
The Seiran aircraft, specifically designed for submarine deployment, were crucial for the plan. Compact yet capable, these aircraft provided Japan with the means to strike the U.S. mainland from the relative safety of the sea. A fleet of nine I-400 submarines was prepared for the mission, each carrying three Seiran aircraft.
Choosing a Suitable Target
The selection of suitable targets was a crucial aspect of Operation PX. San Diego and San Francisco were chosen as the main targets. Both cities had significant strategic and symbolic value, and their coastal locations made them easier to reach for the submarine fleet.
San Francisco, with its bustling harbor and large population, was an attractive target for the operation. The aim was to spread the disease rapidly in densely populated areas, causing widespread death and terror, and disrupting the U.S. war effort.
San Diego, home to a significant U.S. naval presence, was another prime target. A successful biological attack here would severely impair the American Pacific Fleet, slowing down or potentially halting naval operations in the Pacific theater.
Why was Operation PX Cancelled?
Despite meticulous planning and preparation, Operation PX was ultimately cancelled. The major opposition came from Chief of General Staff Yoshijirō Umezu, who was deeply opposed to the operation’s ethical implications.
Umezu, a high-ranking military officer, believed that the use of biological weapons was a war crime. He argued that if Japan initiated such an attack, it would lead to harsh retaliation from the Allies and further isolation of Japan in the international community.
Moreover, there were practical considerations as well. The success of the operation was far from guaranteed, and it would require significant resources, including the use of Japan’s limited number of long-range submarines. These resources could be used more effectively in defending the homeland.
Furthermore, there was an understanding within the military leadership that Japan’s position was already precarious. There was little confidence that Operation PX could turn the tide of the war, making it an unnecessary risk. These considerations led to the eventual cancellation of the operation.
Learning of Operation PX
For decades after the end of World War II, Operation PX remained a closely guarded secret. It wasn’t until 1977, when Eno Yoshio, a former military officer and participant in the operation’s planning, disclosed the operation during an interview with the Japanese newspaper Sankei.
Yoshio chose to wait for over thirty years before revealing the plan’s existence. His reasons for the delay were multifaceted. He was wary of the damage the revelation could inflict on Japan’s post-war reputation. Additionally, the Japanese government had a policy of keeping war crimes classified, and it was only in the 1970s when Japan began acknowledging and dealing with its war past more openly.
The disclosure of Operation PX has since ignited significant historical interest, leading to further research and investigation into Japan’s wartime activities. Today, it stands as a chilling reminder of the extreme lengths to which nations were willing to go in their pursuit of victory during the Second World War.
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