A Star Wars fan in an R2-D2 costume poses for a photo outside the venue during a fan convention called the Star Wars Celebration in Chiba, near Tokyo, Friday, April 18, 2025. (Photo by Hiro Komae/AP Photo)

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)

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)

A rickshaw man runs under the blooming cherry blossoms in Tokyo, Sunday, March 29, 2015. (Photo by Shizuo Kambayashi/AP Photo)

An employee of Daikin Industries Ltd works the production line of outdoor air conditioning units at the company's Kusatsu factory in Shiga prefecture, western Japan March 20, 2015. As Japan heads into the season of peak demand for room air-conditioners, Daikin managers have been tasked with figuring out how to boost output by some 20 percent at the 45-year-old Kusatsu plant that six years ago the company had almost given up on as unprofitable. (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.