Not simply as a means to get clean, "sento," or public baths, have traditionally been places where communication flowed. Bathing and chatting together with one's friends and neighbors in the buff exemplifies the off-guardedness of the most informal relationships.
The practice goes back centuries, with roots, many believe, in Buddhism.
In recent years, however, neighborhood sento have dried up as more private homes become equipped with their own baths. In many cases, sento have evolved into large spa facilities such as "super sento" or "health lands," where everything from baths to body massages are available.