From the Desk of Ross Coen: When History Has More to Say

The following is by Ross Coen, author of Fu-go: The Curious History of Japans Balloon Bomb Attack on America (Nebraska, 2014). Cohen is a historian who writes about the American West, Alaska, and the Arctic. 


When History Has More to Say

Every historian knows how exciting and yet terrifying it can be to discover new evidence after your book is published. It’s exciting because we never stop being interested, and learning something new just adds to the thrill that drew us to the subject in the first place. But it’s also terrifying when the new evidence stands to disprove or even just slightly refute one’s claims and conclusions.

I experienced both emotions last month while visiting the Defunct Imperial Japanese Army Noborito Laboratory Museum for Education in Peace, located just outside Tokyo.

In my book Fu-go: The Curious History of Japan’s Balloon Bomb Attack on America, I tell the story of one of the most unique weapons of World War II. In the latter stages of the war, Japan launched thousands of hydrogen balloons knowing that once they ascended to 30,000 feet and entered the strong westerly winds of the upper atmosphere they would be carried to the United States in about four days. Each balloon was armed with explosives in the hopes they would ignite wildfires in western states that the Americans would fight with resources that otherwise might be used in the Pacific war. The Japanese also intended fu-go—an abbreviated code name for fusen bakudan, or “balloon bomb”—to be a weapon of terror. Bombs raining down silently from above, Japanese military officials believed, would surely weaken the Americans’ resolve.


When dozens of balloons began arriving everywhere from Oregon to Alaska in the winter of 1944-45, the U.S. military recognized the potential for wildfires. But its greatest fear was that the balloons might be weaponized with bacterial or biological agents that could spread illness to people and livestock. Indeed, the War Department enlisted whole teams of doctors, pathologists, bacteriologists, and veterinarians to study every scrap of balloon material that could be recovered and to keep close watch for disease outbreaks among wild and domesticated animals.

No such agents were ever found, not a single microbe out of place. After the war, American scientists interviewed their Japanese counterparts at the Noborito Research Institute (where the balloons had been designed and engineered) and were told the Japanese had never seriously considered using the balloons to wage biological warfare.

And that’s what I wrote in my book, which came out in 2014.

Last month, while attending a conference in Tokyo, I visited the old Noborito Institute, now a museum on the campus of Meiji University. Many artifacts from the war years are on display, an effort to promote lasting peace by confronting the horrors of past wars.

I received a guided tour from Maho Shiina, who generously translated for me some archival records of the institute’s balloon research in the 1940s. She also translated a few articles written many years after the war by engineers who had worked on the balloon program. One article was a 1990 memoir by Noboru Kuba, a veterinary major, who handily disproved my conclusion that the Japanese had never planned to weaponize the balloons with biological agents.

cohen_blog post 3
Maho Shiina, staff member of the Defunct Imperial Japanese Army Noborito Laboratory Museum for Education in Peace, shows Ross Coen archival records of Japan’s WWII balloon bombs. Photo by Jessica Lane.

“My research purpose was epidemic diseases on livestock,” Kuba wrote. “If it could have been realized, Japan could damage the U.S. by limiting cow’s milk production. The final goal was a stratagem that the enemy country would give up the war.” Kuba went on to note that his research showed promising results—ten cows were killed in a controlled study—and that by September 1944, his team had effectively engineered a powderized poison that could be delivered via balloon. The Imperial Army leadership decided against the offensive, however, fearing massive retaliation by the United States.

Kuba’s admission is not particularly surprising given the well-documented history of Japan’s biological and chemical weapons programs of that era. And yet it came as a shock to me. In the seven years of researching my book, I examined tens of thousands of archival documents, and never before had I seen anything like this one. All records of the balloon bomb campaign were destroyed immediately after the Japanese surrender in August 1945, and thus it was easy for officials at that time to deny the development of biological weapons. Even while writing my book, I suspected the Noborito engineers at least considered weaponizing the balloons. But with the postwar denials my only sources on that point, I wrote otherwise. I am extremely grateful to Noboru Kuba for his memoir and to Maho Shiina for locating and translating this invaluable source.

Should my book ever come out in a revised second edition, I have something new to say.

One thought on “From the Desk of Ross Coen: When History Has More to Say

  1. My husband and son, both land Surveyors found a Japanese balloon bomb ballast in a vacant field near Wenatchee, Wa.
    See his post on Facebook to view picture. Brian McNeill Wenatchee

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