Okunoshima

Origin Story

Okunoshima is a small island in the Seto Inland Sea, a fifteen-minute ferry ride from the town of Tadanoumi. In 1929, the Imperial Japanese Army chose it for a chemical weapons plant precisely because it was small, isolated, and easy to hide: far enough from Tokyo to protect the capital, close enough to the mainland to supply. From then until 1945, the island was removed from official Japanese maps. Workers were sworn to secrecy, residents were relocated, and ferries passed an island that officially was not there.

Evidence & Claims

Over sixteen years the plant produced more than 6,000 tons of mustard gas and other chemical agents, in violation of the Geneva Protocol Japan had signed, much of it used in China during the war. Thousands of workers, including mobilized students, handled the agents with inadequate protection; survivors suffered chronic lung disease for decades and were largely unacknowledged until the government began issuing certificates and compensation years later. The island's Poison Gas Museum, opened in 1988, documents all of this in unsparing detail. The ruins of the power plant, storerooms, and gas storage bunkers still stand fenced but visible around the island. The famous rabbits, hundreds of them, tame enough to climb onto visitors, are of disputed origin: descendants of test animals released at the war's end by one account, of schoolchildren's pets by another. The museum favors the second explanation; the first refuses to die.

Skeptical Explanations

Nothing about Okunoshima's history is in doubt; it is one of the best-documented cases of a state deleting a place from its own geography. The open questions are smaller and stranger: where the rabbits actually came from, how much contaminated material remains sealed on and around the island (dumped munitions are still periodically found in the surrounding sea), and how a site of industrial atrocity became one of Japan's most photographed animal-tourism destinations. The island holds both identities at once, which is exactly why people find it hard to look away.

Reached by frequent ferries from Tadanoumi Port (about 15 minutes; the port is a short walk from Tadanoumi Station on the JR Kure Line). The island has a hotel, campground, and free-roaming rabbits; visitors are asked not to feed them snacks or handle them roughly. The Poison Gas Museum is open roughly 9 a.m. to 4:30 p.m. for a small fee; photography is not allowed inside. The factory ruins are fenced: view from outside only.