Ganbanyoku

Ganban'yoku (岩盤浴^?) is Japanese term for a popular form of hot stone spa. It is said to have originated in Thailand.^{[citation needed]}
Body-sized stones, such as granite, are inserted into the floor and heated. Bathers lie clothed on the stones while their bodies gradually heat up.
Like low temperature saunas, ganban'yoku are commonly advertised to have a detoxification effect, improve the circulatory system and are good for the skin.
Many spa facilities, including Spa LaQua at Tokyo Dome City, have ganban'yoku rooms.