For Hideo Yasunami, a 60-year-old innkeeper in Beppu, Oita Prefecture, "jigokumushi ryori" — literally "hell-steamed cuisine" — was just a local dish of seafood and vegetables steamed in water from the city's famed hot springs.

"It's an ordinary recipe in the community. I never imagined it would be a resource for invigorating tourism," Yasunami said of the culinary method, which accentuates the sweetness of the ingredients thanks to the hot springs' steam that the locals liken to plumes from hell.

He took a chance and started serving jigokumushi dishes in 2001 at an open-air stall at his inn, Daikokuya.