Tatami, 畳

Traditional Japanese flooring made of woven straw and trimmed with cloth.

You know what tatami is. Made popular as sandal soles and coasters in the last 5 years, this ubiquitous Japanese material actually has a long history.

Once only used by Japanese elite, by the end of the 17th century tatami covered the floors of most Japanese houses. In fact, tatami is so essential in a Japanese home that rooms are measured, not in inches or centimeters but in mats (called jō). The shape of tatami mats is strictly regulated though regional differences exist—mats from the west of Japan are slightly larger from eastern varieties. But before you go slapping down mats over your linoleum floor, familiarize yourself with the strict rules governing the placement of tatami. Three corners can never touch and laying a grid pattern is worse than breaking a mirror. But if you want a taste before you invest, there is nothing in the rulebook about having a little tatami inside your shoes.