Operation Cherry Blossoms At Night
Transcript
On August 6th and 9th of 1945, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasak. The act was an extraordinary measure, the first of its kind, that would forever alter the course of military doctrine. They didn’t know it at the time, but these actions were taken just weeks before another awful and shocking attack was planned - this time by the Japanese on the American mainland.
Starting on September 22, five I-400 class submarines were to travel across the ocean into striking range of the US. The submarines would surface and each launch 3 Aichi M6A Seiran attack planes. These planes would target population centers in Southern California, dropping bombs meant to kill and shock military and civilian targets alike. The bombs were not conventional explosives however, nor even nuclear. Instead, these specially designed ceramic bombs were designed to break open and spread millions of fleas - fleas infected with bubonic plague, with the goal of sickening and killing thousands. This was the innocuously-named Operation Cherry Blossoms at Night.
Although the idea of a mass biological attack on American land during World War II may seem quite shocking to us, it’s a sad reality that this type of attack was practiced and refined against other civilian targets in both Japan and China.
Plenty of others have covered Unit 731, Japan’s secret division for biological and chemical weapons development, and there’s honestly a lot to discuss so I’m not going to go into the full story here. But, there is the chance to come back to them for a more thorough discussion, so feel free to leave a comment if you’d like me to get into that.
Here’s what we need to know for now: Unit 731, officially called the Epidemic Prevention and Water Purification Department, was a covert unit tasked with the development and testing of chemical and biological weapons. They were known to have experimented with such diseases as typhoid and paratyphoid fever, bubonic plague, cholera, anthrax, dysentery, and botulism. In all, over 500,000 deaths are blamed on germ warfare and human experimentation efforts of the Imperial Japanese Army. It was Unit 731 where the biological material and delivery systems for these attacks would be refined, and from where the plan would be hatched to release them against the US.
Although Operation Cherry Blossoms at Night was the largest such attack planned by the Japanese against the Americans, it was not the first that was considered. Biological weapons were considered against the Americans in the Phillipine Campaign before their surrender at Bataan. Two gliders full of biological munitions are also reported to have been planned for use at the Battle of Iwo Jima, but for some reason or another did not make it to their intended destination. The Japanese had also previously launched another attack against the mainland US, using a series of “fire balloons” carried by jet streams to hit the States and cause fires. Despite being considered the first intercontinental strike recorded, this attack caused only minor damage with 6 civilian deaths and a farm being the extent of recorded casualties.
Surgeon General Shiro Ishii, leader of Unit 731, had proposed a biological attack on America at an earlier occasion but the plan had been denied due to logistical issues with the number of submarines available for the attack. He again pushed the plan closer to August of 1945, when wartime production had advanced ahead of schedule and more submarines were expected to be available for the attack - with enough submarines expected to be finished by September 15th of 1945.
The I-400 submarines which the operation planned to use were some of the most technologically advanced of the time, and had the range to reach nearly anywhere in the world and return to Japan. The Seiran aircraft were developed specifically for use with the I-400 submarine, which would launch them by use of a compressed air catapult. The Seiran aircraft was capable of accepting floats which would allow the craft to launch and be recovered, but doing so would have doubled the required launch time from 15 to 30 minutes for all 3 planes - and it’s widely accepted that Operation Cherry Blossoms at Night and similarly planned attacks would likely have turned into kamikaze missions for the pilots involved.
Of course, today we know how the war ended. Faced with the destruction of nuclear weaponry along with a pending invasion by the armies of both the United States and Russia, Emperor Hirohito announced Japan’s intent to surrender on August 15th and signed a formal declaration on September 2nd. On August 22nd, Japanese submarines received an order to destroy all their sensitive equipment. All torpedoes were fired off and the Seiran aircraft were launched with their wings folded, being swallowed by the sea.
After the official end of hostilities, the US Navy boarded 24 Japanese submarines including the 3 I-400 class submarines that had been built at the time. There was an eagerness not only to gain intelligence about the technical capabilities of the vessels, but to prevent them from being examined by the Soviets. A number of submarines were deliberately sunk in Operations Dead Duck and Road’s End, while the remaining were brought back to Pearl Harbor for further testing before also being sunk in undisclosed locations.
Prior to the end of the war, the existence of Seiran aircraft was not known to the US or Allied Intelligence. A total of 28 are believed to have been made, and today only a single example remains. It has been restored and is currently on display at a National Air and Space Museum Center in Virginia.
Today, there’s some debate over whether Operation Cherry Blossoms at Night was feasible and would have the impact anticipated. It’s considered likely that enough submarines to support the operation would have been completed had the war not ended when it did, and there’s little doubt that a successful biological attack against American citizens would have had profound psychological impacts on the people. However, others believe that biological weapons use may not have had the same impact in the US as in China, as US access to better health care as well as a lower population density could have considerably mitigated the spread and casualty of infection.
If there’s one thing that’s associated with World War II in particular, it’s a heavy cost in human suffering as terrible new technologies were unleashed. 3 quarters of a century later, we can look back with relief that the success of Operation Cherry Blossoms at Night ended up being a question of historical speculation, an answer we didn’t end up having to learn from experience.
Thank you for sharing your time with me as I discussed this strange and frightening moment in world history. If you enjoyed listening to this episode, consider subscribing on YouTube or following me on your podcast platform to stay informed of new episodes. And for my YouTube people, please consider leaving a like or a dislike depending on how you felt about this video and a comment with any feedback you may have - every interaction has a tangible impact on the reach of the show. Until next time, it’s been a pleasure as always. Thank you.
