Ohyu-ya, Todaiji Temple


It wasn't until after the Nara period that the original form of sento, as an artificial structure, first appeared. It is thought that the original baths were used to purify Buddhist images with hot water. Thus, a kind of bathroom known as a 'tera-yu', or temple bath, came to be built in temples here and there, for use in Buddhist religious services.
As for the ones opened to the public, that became known as 'Hodokoshi-yu', the oldest surviving one in existence is 'Ohyu-ya', built by the Empress Komyo at the Todaiji temple in Nara city. However, in those days the way of bathing seems to have been a combination of cold water and steam baths, and we must wait until the Edo period before we see the appearance of the first hot bath.