(茶室, literally “tea rooms”) in Japanese tradition is an architectural space designed to be used for tea ceremony (chanoyu) gatherings.
The architectural style that developed for chashitsu is referred to as the sukiya style (sukiya-zukuri), and the term sukiya (数奇屋) may be used as a synonym for chashitsu. Related Japanese terms are chaseki (茶席), broadly meaning “place for tea,” and implying any sort of space where people are seated to participate in tea ceremony, and chabana, “tea flowers”, the style of flower arrangement associated with the tea ceremony.
The ideal free-standing tea house is surrounded by a small garden having a path leading to the tea room. This garden is called roji (露地, “dewy ground”). Along the path is a waiting bench for guests and a privy. There is a stone water-basin near the tea house, where the guests rinse their hands and mouths before entering the tea room through a small, square door called nijiriguchi, or “crawling-in entrance,” which requires bending low to pass through and symbolically separates the small, simple, quiet inside from the crowded, overwhelming outside world. The nijiriguchi leads directly into the tea room.
Chashitsu are broadly classified according to whether they have a floor area larger or smaller than 4.5 tatami, a differentiation which affects the style of ceremony that can be conducted, the specific type of equipment and decoration that can be used, the placement of various architectural features and the hearth, and the number of guests that can be accommodated. Chashitsu which are larger than 4.5 mats are called hiroma (literally, “big room”), while those that are smaller are called koma (literally, “small room”). Hiroma often are shoin style rooms, and for the most part are not limited to use for chanoyu.