Jō (tatami Mat) (jō)

JapaneseTraditional unit (still used in some regions)Approximate value

Half a tsubo, about 1.653 m², the area of one tatami mat. Mats vary by region from about 1.44 to 1.82 m², and Japanese real-estate rules set a minimum of 1.62 m² per jō in advertisements.

1 jō (tatami mat) = 1.652892562 square meters (approximately).

Approximate value. Standards for the jō (tatami mat) varied by place and period, so this converter uses the most commonly cited value. Treat results as estimates, not exact figures.

About the jō (tatami mat)

Jō is the counter for tatami, the woven rush floor mats of Japanese rooms, and the word tatami comes from a verb meaning to fold or pile, since early mats were thin enough to be stacked away. Tatami began as seating for the aristocracy in the Heian period and covered whole rooms in samurai and temple houses by the Muromachi era. They reached ordinary homes only in the late 17th century.

Because a mat was a standard building module, rooms are still described as six jō or eight jō. A mat is about twice as long as it is wide, and size varies by region. Kyoto mats measure about 191 by 95.5 cm, around 1.82 m2, Nagoya mats about 1.65 m2 and Tokyo mats about 1.55 m2. Apartment-block mats can be smaller, near 1.44 m2.

Wikipedia takes the Nagoya mat as the reference, which makes one jō half a tsubo, exactly 200/121 m2 or about 1.653 m2, and that is the figure used here. A separate figure of 1.62 m2 is the minimum area per mat that Japanese property advertising rules allow when a room is described by its mat count, so it is a legal floor rather than a typical mat.

Sources: Wikipedia: Japanese units of measurement; Wikipedia: Tatami; Real Estate Tokyo: Units used for real estate size in Japan

Jō (tatami Mat) conversion chart

1 jō (tatami mat) expressed in every other area unit:

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