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Hiroshima for Global Peace

The Island Erased from the Map, Okunoshima





Left: 1932 survey, published in 1947 Right: 1932 survey, published in 1938

As seen, Okunoshima has been unnaturally erased.

Source: 1/50,000 scale topographic map published by Geospatial Information Authority of Japan.



Okunoshima (Takehara City, Hiroshima Prefecture), a national park designated for about 4 kilometers in circumference, is known as the “Rabbit Island” where about 900 rabbits live. Many tourists, both domestic and international, visit the island every year. However, Okunoshima was once called “the island that was erased from the map.” From 1929 to 1945, Okunoshima was a location for producing poison gas for use in World War II. It was erased from the map as a national secret of Japan’s major chemical weapons production base. Historical sites related to the production of poison gas still remain on Okunoshima today and continue to tell the horrors of war.





War Ruins of Okunoshima _ Power Plant Site

During World War II, the power plant supplied electricity for producing poison gas, and at the time there were eight generators fueled by heavy oil. During the Korean War, it was used as an ammunition depot for the U.S. military, and the abbreviation “MAG2,” referring to the ammunition magazines, still remains on the wall.





War Ruins of Okunoshima__ Poison gas storehouse in Nagaura

The largest of the island’s poison gas storage facilities was the former Nagaura poison gas storage facility, where six tanks containing approximately 100 tons of poison gas were stored. The huge storage tanks and their concrete pedestals remain today. After the war, it was burned down with flamethrowers to remove the toxicity.





War Ruins of Okunoshima _ Northern and Central Batteries

During the Sino-Japanese War and Russo-Japanese War, to defend the Seto Inland Sea, batteries were established at three locations on the island. Four 24cm cannons and four 12cm cannons were installed in the northern battery (left), six 28cm cannons that were the mainstay of the battery (right), and four Ska-9 cannons were installed in the southern battery, and the remains of the gun emplacements still remain today.





War Ruins of Okunoshima_Gunpowder Depot

There was a gunpowder depot that stored ammunition and gunpowder for batteries during the period of the Geiyo Fortress (ca. 1904) and was a product storage area for poison gas during World War II. The walls were made of bricks, but the roof was lightly constructed in consideration of explosion accidents. An earthwork had been built on the seaside to blindfold it from the visitors.





The Poison Gas Museum

Okunoshima, where a large quantity of poison gas weapons were once manufactured, has now been developed as a national vacation village. Only a few remnants of those days remain, such as the ruins of gun batteries, power plants, and poison gas storage facilities. The Poison Gas Museum was built in 1988 to convey the fact that poison gas was produced on Okunoshima, the tragedy and reality that many victims were killed in the process, as well as the wish for lasting peace. The museum has become one of the most popular places for peace education, with valuable documents such as workers’ notebooks, work uniforms, and liquid poison gas production equipment on display.

An official from Takehara City says, “In the past, many people lost their lives in Okunoshima due to the production of poison gas. We wold like you to know that many people are still suffering today (*1), and at the same time, we would like you to learn the importance and appreciation of the peace we have today, while you can enjoy interacting with rabbits”. When you visit Okunoshima, please visit the Poison Gas Museum and the historical sites related to the production of poison gas. I’m sure you’ll find the adorable rabbits even more precious.


Tel: +81 (0)846-26-3036

Address: 5491 Tadanoumi-cho, Takehara City

Opening hours: 9:00 – 16:30 (last admission at 16:00)

Closed: New Year holidays

Fee: 150 yen for adults (over 19 years old), 120 yen for groups of 20 or more

*Those under the age of 19 and those who have a physical, mental, or psychiatric care certificate are exempt from the entrance fee.





Okunoshima DATA

Tel: +81 (0) 846-26-0321 (National Vacation Village Okunoshima 9:00-17:00)

Address: Okunoshima, Tadanoumi-cho, Takehara City, Hiroshima Prefecture



  • From Tadanoumi Station (JR Kure Line), walk 7 minutes to Tadanoumi Port and take the Omishima Ferry for 15 minutes.
  • Take a 5 minute bus from Takehara Station (JR Kure Line) to Takehara Port, then take the “Rabbit Memories” route for about 20 minutes.



(*1) In 1974, the Japanese government enacted the “Outline of Relief Measures for Persons with Poisonous Gas Disorders”. Thanks to this Relief Measures, all persons with disabilities regardless the engagement of the production of poisonous gas would be covered by social security. In 1952, Hiroshima University’s predecessor, the Hiroshima Medical College, started a volunteer program of mass medical examinations, which ended in 2016. Today, the individual examination in a designated hospital is carried out.


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