Pedestrians walk past an art installation by French street artist James Colomina called the “The Briefcase” (bottom) at Shibuya Crossing in the Shibuya district of central Tokyo on May 20, 2025. The display shows a red briefcase – a symbol of work and conformity – with arms, legs and a tie poking out on the ground to illustrate a “salaryman” who has lost his identity, swallowed by his daily routine. (Photo by Richard A. Brooks/AFP Photo)

Women wearing braided straw hats dance as the Owara Kaze-no-Bon dance festival begins on September 1, 2025 in Toyama, Japan. The festival, believed to have more than 300 years history, continues till September 3. (Photo by The Asahi Shimbun via Getty Images)

People walk through Ginza’s shopping district in Tokyo, Japan, 15 December 2025. Japan’s economic focus is on the upcoming Bank of Japan (BOJ) meeting where the central bank is expected to raise its policy rate to combat inflation. The BOJ signaled a rate hike bar is cleared with the wage momentum still intact. (Photo by Franck Robichon/EPA)

Dancers dressed as futuristic characters perform during a show at The Robot Restaurant on June 29, 2014 in Tokyo, Japan. The now famous Robot Restaurant opened two years ago in Kabukicho area of Shinjuku at an estimated cost of 10 million U.S. dollars. Performances are held three times a day and cater mostly to foreign tourists. The cabaret style shows include bikini clad futuristic dancers, performers dressed as robots and a host of large scale robots and vehicles controlled with remotes by stage hands dressed as Ninjas. (Photo by Chris McGrath/Getty Images)

Japan Self-Defense Force (JSDF) soldiers and firefighters make rescue works among mountain lodges, covered with volcanic ash near the peak of Mt. Ontake, which straddles Nagano and Gifu prefectures in this September 28, 2014 photo taken and released by Kyodo. More than 30 people were feared dead on Sunday near the peak of the Japanese volcano that erupted a day earlier, sending a huge cloud of ash and rock tumbling down its slopes, while packed with hikers. (Photo by Reuters/Kyodo News)

Men ride on a “mikoshi” or portable shrine as local people carry it into the sea during a festival to wish peace in the ocean and good fortune in the new year in Oiso, west of Tokyo, January 1, 2015. (Photo by Yuya Shino/Reuters)

Only after World War II did the secret spill: Ōkunoshima, located in the Inland Sea of Japan between Hiroshima and Shikoku, was the top-secret site for manufacturing chemical warfare. When the factories were closed down, a number of exotic wild rabbits were seen freely roaming the island. They were assumed to have been the test subjects for the chemical weapons, which the military failed to eradicate when the factory was demolished.