Okunoshima, a small island in Japan’s Seto Inland Sea, leaves a lasting impression long before its full story is known. What appears today as a cheerful stop filled with free-roaming rabbits and camera-happy visitors once operated as a hidden center for chemical weapons.
This sharp contrast defines the island’s identity. Okunoshima is admired for its gentle animals and scenic coastline, yet it also carries the weight of a past marked by secrecy, suffering, and unresolved responsibility.
A Quiet Arrival That Quickly Changes
The ferry ride offers few hints of what awaits. Bunny-shaped decorations on the windows serve as the only clue. Once passengers step ashore, movement stirs in the bushes. A single rabbit appears, calm and unafraid. Another follows. Within minutes, visitors find themselves surrounded.
A short walk along the shoreline leads straight into rabbit territory. Groups of rabbits gather for food, chasing one another away from piles of Chinese cabbage and pellets brought by tourists. Smiles and cameras fill the scene, as visitors react to how close and trusting the animals are.
Volunteers leave shallow bowls of water across the island. With limited natural vegetation, these areas act as feeding hubs for an estimated 400 to 500 rabbits. The animals now rely on human support rather than their original diet of grass, bark, roots, and fallen leaves.
Life on an Island Without Residents
Instagram | outdoor | Okunoshima lacks permanent residents, leaving its future and rabbit population uncertain.
Despite its popularity, Okunoshima has no permanent residents. Only hotel staff and guests stay overnight. The island’s future, along with the survival of its rabbits, remains uncertain.
From 1929 until the end of World War II, Okunoshima served as a secret base for the Japanese imperial army. Poison gas was researched and produced here under strict secrecy. At the time, the island was removed from official maps of Japan.
Workers in rubber suits, gloves, long boots, and gas masks manufactured mustard gas, along with smaller amounts of tear gas and cyanide. These weapons were later used during the Sino-Japanese War and in balloon bombs sent toward the United States.
How Rabbits Became Part of the Story
Rabbits first arrived during the war years. Around 200 were used in experiments to test the effects of chemical weapons. As Japan faced defeat, efforts were made to destroy evidence of these operations, including the extermination of laboratory rabbits.
The current rabbit population likely has a different origin. In the early 1970s, a nearby elementary school released rabbits on the abandoned island, hoping to bring life back to the area. Over time, the animals multiplied.
In 2024, nearly 200,000 visitors came to Okunoshima, drawn by its coastline and the promise of a rabbit-filled experience that plays well on social media.
Tourists, Volunteers, and Daily Survival
Koji Yamamoto, a retired visitor, first came to Okunoshima five years ago out of interest in wartime history. The rabbits are what keep him returning.
“This is my 30th time here,” Yamamoto says while watching grey rabbits eat pellets he placed on the ground. “There isn’t much natural vegetation, so I thought it would be a good idea to come regularly and feed them, especially during the winter when there aren’t many tourists.”
Yamamoto stays until every pellet is eaten. If food is left unattended, wild boar and crows often move in. These animals not only steal food but have also attacked rabbits.
Science, DNA, and Lingering Questions
Some visitors believe today’s rabbits may be linked to those used in wartime experiments. Shingo Kaneko, a professor in the faculty of symbiotic systems science at Fukushima University, has studied the rabbits’ DNA to explore this possibility.
The conclusion points elsewhere. “Even if an individual rabbit survived [the wartime experiments] it would have been very difficult to continue its lineage,” Kaneko explains. “But I can’t say 100% no, and it’s a story that people like to believe could be true.”
Kaneko’s research, based on hundreds of droppings, shows wide genetic variation. This suggests rabbits were released on the island multiple times, often by people leaving unwanted pets.
Dependency and Decline
Rabbits on Okunoshima can no longer compete for food in the wild. According to Kaneko, they depend fully on visitors and volunteers.
“They depend on people for food, and that’s not good. There is not enough natural food,” he says. “The rabbits look happy enough in social media posts, but they have an increasingly precarious existence.”
After a rise in numbers following the lifting of coronavirus restrictions, signs now point to another decline. Fewer visible droppings suggest the population may be shrinking again.
Abuse and Growing Concern
Instagram | outdoor | Reports of rabbit cruelty on Okunoshima have sparked global animal protection concerns.
The island faced global attention after reports of cruelty. Ryu Hotta, a 25-year-old, received a suspended prison sentence for abusing rabbits by kicking them or inserting scissors into their mouths. Media reports stated that 77 rabbit carcasses were found on Okunoshima between November 2024 and January of the following year. The exact number linked to abuse remains unclear.
This incident raised serious questions about animal protection on an island built around open access.
Remembering What Came Before
While most visitors come for the rabbits, Okunoshima’s history risks being overlooked. Kazuhito Takashima, who manages the Poison Gas Museum, sees this firsthand.
“About 85% of people who visit Okunoshima come to see the rabbits and give this place a miss,” Takashima says. “Most Japanese people have no idea about the poisonous gas facilities … we didn’t learn about this kind of thing at school.”
The museum displays gas masks, factory uniforms, and photographs showing injuries suffered by workers exposed to toxic chemicals. A hinomari yosegaki flag, inscribed with “shuku nyūei,” wishes soldiers success and safety in war, offering a quiet reminder of the era.
Departure and Reflection
As visitors board the Lapina pleasure boat, final photos of rabbits fill their phones. Souvenir shops on the mainland wait just 15 minutes away. The experience often ends on a cheerful note, yet questions linger.
“There are lots of tourists now, but there is no guarantee that will always be the case,” Kaneko says. The island’s challenges have changed, but they remain real.
Okunoshima stands as a place shaped by contrast. Its connection to poisonous gas ended 80 years ago, yet the impact still echoes through abandoned buildings and museum walls. At the same time, its rabbits draw attention, care, and concern from around the world.
The island’s future depends on whether both sides of its story can be acknowledged and protected, without letting one erase the other.