yojōhan 四畳半

A four and a half 4 1/2 mat tea ceremony room *chashitsu 茶室, the most common size room. Mats are usually 190.95 cm x 95.45 cm, but the room may be larger with the addition of various structural elements. The calculation of the tea ceremony room size is called tatamiwari 畳割 and is mainly used in the Kansai 関西 area, but seems not to have influenced tea ceremony structures in the Kyoto area. Typically, the half mat is placed in the center of the tea ceremony room. When the sunken fire-box *ro 炉 is placed into this mat, it is called *ro-datami 炉畳. The other mats are placed, one after the other in a pattern called the chase-around type.
In a 4 1/2 mat tea ceremony room in the normal position hongatte 本勝手, the alcove is on the right at the back of the room. The mat for a high ranking guest *kinin-datami 貴人畳 is at the front of the alcove. In the front wall near the guest mat *kyaku-datami 客畳 is a small crawl-in or wiggle-in entrance. It has an entrance mat called a *fumikomi-datami 踏込畳. This tea ceremony room should also have a utensil mat *dōgu-datami 道具畳, which will sometimes double as the host's mat *temae-datami 点前畳.
These mat positions are only used in the fall and winter when a sunken firebox is used. In the spring, the firebox is covered and a portable stove *furo 風炉 is used to heat water. The kinin-datami and dōgu-datami remain as they are, but the two guests mats are placed in front of the kinin-datami. The half size mat is set in front of the host's entrance *sadōguchi 茶道口, and is called a step-in mat. The *gyakugatte 逆勝手 method exactly reverses these normal positions.
The yojōhan tea ceremony room is attributed to Murata Jukō 村田珠光 (1422-1502) and became a formal type tea ceremony room during the time of Takeno Jōō 武野紹鴎 (1504-55). It became the dominant tea ceremony room during the time of Sen no Rikyū 千利休 (1522-91).