Okunoshima, better known as Rabbit Island, sits in the Seto Inland Sea off Hiroshima. It looks like paradise now: hundreds of tame rabbits hop up to greet every visitor who steps off the ferry. But the island hides a dark past. From 1929, the Imperial Japanese Army secretly produced poison gas here, so secret that the island was rubbed off some maps. Over six thousand people worked the factory, and thousands of tons of chemical weapons left its shores before the war ended in 1945.

Afterwards the factory was dismantled, and in the 1970s a handful of rabbits were released on the island. With no predators, they multiplied into the friendly army you meet today. The ruins are still scattered everywhere, the old fort batteries and the shells of the gas plant slowly crumbling, most of them fenced off as too dangerous to enter. It is one of the gentlest and one of the grimmest haikyo I have ever visited, both at the same time.