Perhaps your readers will be interested, he wrote.

Duncan Williams grew up in Japan. What he missed most after he left were Buddhist temples and onsen. Now he is back, finishing his Ph.D. dissertation for Harvard on Edo Period Buddhism. His research focuses on the long relationship between Buddhism and hot springs. You may think this is a topic of rather limited interest, but you would be wrong. There are enough experts on the subject to provide monthly speakers for the Kokusai Butokai, an international association for the study of Buddhism and hot springs, and to assemble an interested audience which comes not only for learning but also to enjoy an onsen session. Meetings are held alternately at two Tokyo onsen. First the bath, then the lecture. Obviously, it will be a relaxed environment.

You can join for 5,000 yen a year, an amount that will prove a good investment for those who attend the three meetings held at famous Buddhist-related onsen during the year since members receive a generous discount at the selected inn. The next trip will be to Yamagata this summer. Anyone can attend the meetings, although nonmembers will be responsible for onsen charges, food and drinks.

While membership is international, you should know that most of the lectures and discussions are in Japanese. Among the exceptions: Duncan will be lecturing in English in July, as will a German woman who's also an authority on the subject, sometime this fall. If you don't speak or understand Japanese, you can ask to be notified whenever there is a lecture in English.

The onsen connection has a long history. In Edo days, common people could not travel unless they had a passport from the village headman which could only be issued for a temple pilgrimage or an onsen visit for some curative treatment. It is not surprising that early package tours combined the two and inevitably a temple/onsen relationship developed with entertainment areas growing around them. Women, too, could travel on pilgrimages and groups comprising members of women's associations were not uncommon.

Long before that, there were many stories of Buddhism and hot springs. The Shuzenji hot springs in Izu, for example, have been under temple management for some 1,200 years. It is said that the great priest Kobo Daishi, founder of the Shingon doctrine, struck a rock in the river with his staff and hot water gushed out. One of my favorite inns is there, the Arai. Many of the rooms extend partially over streams, there are red lacquer bridges and a beautiful bath in the court style of the 8th century. I am grateful to Kobo Daishi for his contribution.

Shrines, too, have long connections with onsen though Shinto rites are perhaps better known for cold water and the winter devotions held under icy waterfalls. The seven best known onsen in Hakone are connected to the main shrine there. The waters are said to be especially good for healing. Buddhist legends recount how early priests would teach their doctrines to the kamisama, the gods of Shinto, who would be so overcome with joy and gratitude that they would present their hot springs to their Buddhist teachers. Of course these stories are told from the Buddhist perspective.

As Duncan continued his studies, he found that many other people researching history and/or religion had also become curious about the hot spring/Buddhist connection. This inspired him to combine research with the inherent pleasures of visiting onsen, with sake, food and conversation as binders. Then there was the added traditional value of hot spring cleansing and healing. It apparently works very well, this combination of academia and onsen euphoria. And what a challenge! Japan has 28,000 hot springs, the most of any country. Already 1,200 are prepared to accommodate visitors.

Generally, the baths are segregated. In Tokyo, a regulation prescribes it. Mixed bathing may be found at some onsen, but segregated baths are also available. If you have not yet had an onsen experience, here would be a compatible group to guide you in the proper procedures and pleasures. It is quite likely that such holidays could become habit-forming.