Wandering through the small, labyrinthian Kannawa neighborhood in Beppu City is nothing short of dreamlike. Steam spews in dramatic, billowing clouds from hot-spring vents into the sky. Wisps of steam hiss and curl around you, rising from drain pipes and cracks in the road as though the streets are a giant sauna. Beppu is home to the highest concentration of hot springs in Japan: More than 100,000 liters of water gush from its 2,300-odd hot spring sources each minute. But besides being a bather’s paradise, the city is known for…