Okunoshima’s dark past resurfaces, reaching far beyond its fame as Japan’s Instagrammable “Rabbit Island.” Tourists visit for the rabbits and scenic trails. However, few realize the island once held Japan’s largest poison gas factory and a secret weapons program during World War II.
Eighty years ago, this tranquil Seto Inland Sea island served a chilling military purpose. Japan produced mustard gas and other chemical weapons here, even though it had signed the 1925 Geneva Protocol banning such warfare.
Reiko Okada, now 95, vividly remembers her time on the island. At age 15, the Imperial Japanese Army mobilized her to build balloon bombs. These “Fu-Go” devices, crafted from washi paper and konnyaku-root paste, carried incendiaries across the Pacific Ocean.
Okunoshima’s dark past resurfaces through this unusual and eerie wartime weapon. Between 1944 and 1945, Japan launched over 9,000 hydrogen-filled balloons. At least 300 reached the U.S. mainland. While most sparked wildfires, one tragically killed six people in Oregon.
Okada, who later became a hibakusha—a survivor of the Hiroshima atomic bombing—still feels deep remorse. “When I learned people had died in Oregon, I realized my own responsibility in the war,” she said.
Just months after helping build the balloon bombs, Okada entered Hiroshima as a relief worker following the atomic bombing. “It felt like a damp world of maggots crawling inside weakened bodies,” she recalled.
She received two notebooks: a “gas notebook” for her time on Okunoshima and an “A-bomb notebook” for Hiroshima. This rare dual status illustrates her unique and painful wartime experience.
As the war neared its end, the military assigned Okada and other schoolgirls to move poison gas. Despite the sweltering heat, they hauled barrels daily for two weeks. Often, Okada stared at the sea and whispered, “I don’t want to die.”
Okunoshima’s dark past resurfaces again through Okada’s postwar journey. After the war, she studied art in Kyoto and later taught high school in Mihara. Eventually, she published an illustrated book about her wartime experience. She also sent copies to Chinese war victims as a heartfelt apology.
Over the decades, Okada has used art and storytelling to promote peace. Through her voice, she continues to warn against nationalism and the rewriting of history. “Each of us must not be deceived,” she said. “We must prevent war together.”
Japan’s wartime chemical weapons program was enormous. According to postwar U.S. records, Japan produced 6,616 tons of poison gas, stored in more than 7 million shells.
Many of these munitions, shipped to China, were never used. Instead, they were abandoned and later unearthed, posing environmental and health risks.
In 1999, Japan officially acknowledged these weapons to China. Since then, both countries have worked together to dispose of more than 100,000 chemical munitions.
Okada believes Japan must honestly confront its past. “We should accept our role in the war,” she said. “We must reflect, apologize, and seek peace.”
Today, Okunoshima draws travelers with its rabbits and seaside views. Nevertheless, its buried history remains just beneath the surface. Thanks to Okada’s testimony, that forgotten chapter refuses to fade.
