A Touch of Heat in the Cold.(International Edition; WINTER TRAVEL)(Japan's thermal baths)

Byline: Christian Caryl; With Akiko Kashiwagi

Tourists soak their sorrows away in Japan's thermal baths.

Japan boasts some of the best skiing in Asia. Yamagata prefecture, on the country's chilly west coast, is home to the Zao Mountain ski resort, featuring a near-limitless supply of deep powder. But the best part of a Japanese winter is what happens apres ski: an outdoor bath in a steaming hot spring, known as an onsen, with snowflakes drifting all around in the dusk. Though any onsen will do, the Meigetsuso inn (meigetsuso .co.jp) offers a particularly attractive version. Nine of its 20 rooms open onto small, private baths (called rotenburo) where guests can relax in quiet splendor with a view of the snow-covered garden and the mountain behind. Lanterns hand-carved from the snow lend a touch of warm light, and bathers can enjoy a sampling of the premium sakes stored in the inn's cellar.

There are some 28,000 natural hot springs in Japan; of those, about 15,000 come with hotels or inns attached. In 2006, visitors spent 137 million nights in onsen hotels--no small number, considering that Japan's population totals 127 million. Those visitors, of course, increasingly include foreigners as well, who have gradually discovered the peculiar ecstasy to be garnered from lolling around in mineral-rich, volcanically heated water. Yet even so, it probably wouldn't occur to most outsiders that winter is one of the best times to visit an onsen.

At Tadaya, another small ...