Ōkunoshima
Rabbits share a Seto Inland Sea island with the ruins of a secret chemical-weapons complex and a museum that keeps its history visible.
ŌKUNOSHIMA, Japan — Rabbits rest on bare earth above a beach while the wooded islands of the Seto Inland Sea rise beyond them. Elsewhere on the same small island, concrete walls disappear beneath vines and a roofless industrial building stands behind a fence. The nickname Rabbit Island captures its most approachable inhabitants, but leaves a substantial part of the landscape unexplained.
An island removed from maps
Ōkunoshima belongs to Takehara in Hiroshima Prefecture. It is also part of Setonaikai National Park, with coastal paths, wooded slopes and views across the water. The short distances between beach, museum and military remains make its contrasting uses unusually close neighbours.
The Japan Tourism Agency’s military history describes a fishing and farming community transformed by military development. A secret chemical-weapons operation began in 1929. Residents were ordered to leave, and the island was removed from official maps. The agency estimates that production reached roughly 6,500 tonnes of poison gas by the war’s end; chemical weapons made here were used in the war in China.
After Japan’s surrender, Allied forces disposed of the stockpiles by burning, burying and sinking them. The surviving buildings are fragments of that industrial system, rather than picturesque ruins detached from their purpose. Barriers around the structures should be respected.
The Poison Gas Museum, established in 1988, gives the history a human scale. Its exhibits include protective equipment, workers’ documents and accounts of exposure. The official description explains that protective clothing was not completely airtight: workers suffered damage to their skin, eyes and throats. A visit to the museum changes how the factory remains outside are understood.
Rabbits without a tidy origin story
The rabbits’ ancestry is less securely documented. Japan’s national tourism organisation records competing stories, including a schoolchildren’s release in 1971 and a supposed connection to wartime test animals. Those stories should be treated as competing accounts, not an established family tree.
The Environment Ministry’s visitor rules identify the animals as introduced domestic rabbits living in a semi-wild state. Its guidance is direct: do not touch them or feed them from your hand. Watch for rabbits underfoot, keep feeding away from roads, remove leftovers and bring no pets. Older tourism copy encouraging close contact should not override those rules.
Plan the crossing carefully
Hiroshima’s official access guide describes the crossing from Tadanoumi as approximately fifteen minutes. Check the operator’s current departures and return boat before travelling. The separate Mihara Rabbit Line notice says that route remains suspended, including after April 2026; an older timetable lower on the same page is not confirmation of service.
Leave time for the museum as well as the shoreline. The island’s appeal lies in holding both places in view: the inhabited beach and the fenced industrial shell, neither cancelling the other.
Sources
- Japan Tourism Agency: island and walking routes
- Japan Tourism Agency: military history
- Japan Tourism Agency: Poison Gas Museum
- JNTO: rabbit-origin accounts
- Environment Ministry: rabbit rules, September 2024
- Hiroshima: Tadanoumi access and Mihara suspension notice
- FCDO: Japan travel advice and weather, earthquake and tsunami guidance
Researched feature, not a firsthand report. Access and guidance checked 21 October 2026. Confirm ferry operations, obey ruin closures and current rabbit rules, and check Japan’s weather and disaster alerts before crossing; national travel advice highlights typhoons, flooding, earthquakes and tsunamis.
Photographs are archival views and may not show current conditions.
The photographic record
