Tatami

What tatami are

A tatami is a thick floor mat faced with woven rush. In the descriptions held by the National Cultural Properties Database it appears less as a material than as the unit by which the size of a room is stated.

Plans are described in mats. The Fukuda Residence in Kochi Prefecture, built in 1924, is described as eight rooms in three ranks around a twelve-and-a-half-mat room in the south-east corner. The Masujin sake shop in Niigata Prefecture, built in 1934, has a twelve-mat room behind the shop and three rooms of six, six and eight mats upstairs.

Rank follows size. The pine room at Sumiya in Kyoto, built in 1926, is described as a staggered sequence running from a ten-mat entrance room through anterooms of twelve and eight mats to a great room of twenty-three, the rooms growing as one moves inward.

A second written form of the counter also appears. The great reception room at the Suenaga Residence in Ehime Prefecture, built in 1927, is named with that form while its description gives its two principal rooms as eighteen mats each.

Counting in the tea room

In a Chashitsu the count becomes the name of the form. The Insū entry for the former Murayama Residence in Hyogo Prefecture records one room of three mats plus a shortened one and another of four and a half. The four-and-a-half-mat room is the basic size for tea.

That shortened mat is a type in its own right, and it is used for alcoves as well. The tea house at Chikushi Jogakuen in Fukuoka Prefecture is described as having a Tokonoma built to that reduced size.

Mat dimensions varied by region and period, so a count cannot be converted to an area by a single rule. Where a record also gives metric dimensions or a floor area, quoting those alongside is the more reliable course.