"The shortcut to Jozankei is not passable," Tanaka-san says in a grave tone when he appears the next morning. In Japan a sudden change of plans is always met with the gravity of a crisis. In his black suit and apologetic posture, he looks like a funeral director.

We take the long way, a spectacular winding drive through Shikotsu-Toya National Park. In less than an hour, we are surrounded on all sides by raw nature and layers of mountains, snowcapped and overlapping as far as we can see. One of the reasons I chose this part of Hokkaido is the proximity of city and wild nature to each other—unthinkable anywhere else in Japan. Ahead of us is Lake Shikotsu, with its dark-blue center, a caldera lake so deep it never freezes entirely, and edged by two volcanoes and primeval forest.

Passing through a subarctic forest so heavily buried under snow that only the top half of the spruces and firs and beeches are visible, I think of how different this seems from the rest of Japan. Basho declared that the morally superior life, and the artistic ideal, was "to keep friends with the four seasons." How easy this is to do in Hokkaido, where hearty, independent people live so closely with the kind of natural beauty and dramatic seasonal shifts that inform so much of Japanese art and literature and philosophy, but which most Japanese never experience for themselves. The man-made landscape may be relatively new here, compared with the rest of Japan, but the world it inhabits feels the oldest of all, the very place civilization forgot.

We are heading, in a roundabout way, toward Niseko, a ski town created on a volcano complex and lava dome with the heaviest and most consistent snowfall in Hokkaido. But since the weather hasn't let up and skiing is impossible today, I'm happy to be able to stop at Jozankei, a hot springs gorge. There's a small ryokan that Japanese friends of mine raved about.

The streets and sidewalks are damp and steamy as soon as we're off the highway, which puzzles me until Tanaka-san explains that the pavement in Jozankei is heated. In the midst of a conglomeration of ugly high-rise hotels, we find Nukumorinoyado Furukawa, an old country-style ryokan with wood beams, a roaring fire in the fireplace, and an incredible gift shop. For a Sapporoan on a day-trip to a spa town like Jozankei, it wouldnÄôt be unusual to hit three baths in a day, slurping hot soba noodles between soaks. We decide to do the same. Somehow it's even better and more authentic that nobody for miles seems to speak English. Leslee and I pay one thousand yen each (about eleven dollars), the drop-in rate to use the onsen on the eighth floor, which has a faded-linoleum kind of glamour and a wistful view of the city in the falling snow.

Here the mineral water isn't green, Leslee notices, but soft and white and sulfuric. After a few minutes of soaking, she says that she feels better than she has in a long time. "In fact," she confesses, "I am having a wave of incredible well-being. What's in this water?"