Tatami mats (originally meaning “folded & pilled”) are a traditional type of Japanese flooring, made from woven soft rush straw of uniform size and shape.
The traditional dimensions of the mats are a fixed 90 cm by 180 cm in size. However, there are rules concerning the number and layouts of Tatami mats an inauspicious layout may bring bad fortune. In homes, the mats must not be laid in a grid pattern and in any layout there is never a point where all four the corners meet.
Tatami mats are associated with Japanese religious rites and the tea ceremony.
Most modern Japanese homes still have at least one Tatami room, The Washitsu, frequently called a Tatami room in English, is a Japanese room with traditional Tatami flooring. Japanese martial arts frequently use the Tatami mats for protective purposes.