Tatami Japanese straw mat, formerly known as "folding chair", is a kind of furniture for people to sit or lie indoors. Tatami was introduced to Japan, South Korea and other places from the prosperous Tang Dynasty, and it was the material for laying the floor in the traditional bedroom "harmony room" in the prosperous Tang Dynasty. After it was introduced into Japan, it evolved into the floor material of its traditional room "harmony room" and became the place where Japanese families used to sleep-Japanese bed. As early as the end of 16, Japanese society had the practice of building houses according to tatami distribution. Tatami is so important in Japanese family culture that tatami is not only a noun, but also a unit of measurement. Japanese usually calculate the size of a harmonious room not by how many square meters, but by how many tatami can be laid. The area of a tatami is 1.65 square meters.
In some parts of ancient Japan, the amount of house tax was determined by the number of tatami sheets. The area of a tatami is 1.65 square meters. The traditional size tatami is 90cm wide,180cm long and 5cm thick, with an area of1.62m2.. There are also half tatami measuring 90 cm by 90 cm. Because the size of tatami is fixed, in traditional Japanese architecture, the room size is an integer multiple of 90 cm. It is worth mentioning that the tatami in Kyoto and Kansai is slightly larger than that in Tokyo and kanto region. The size of tatami in Tokyo is 85cm× 180 cm, and the area is1.53m2.. It can be used not only as a meeting room and lounge, but also as a guest room. The overhead platform is also a large storage place at home, which can suck all kinds of sundries into the "ground" and leave a streamlined home.
In Japan, the area of a typical room is calculated by the number of tatami blocks, and one block is called a stack. Traditional shops are designed with five and a half stacks (8.9 1 square meter), while tea rooms are often four and a half stacks (7.29 square meters). When laying the combination, there are different arrangements according to the number of tatami. It is said that if placed in a non-feng shui way, it may bring disaster. Except for funerals and large rooms, tatami must not be placed in a grid, that is, there can be no combination of four tatami corners gathered in one place, so the area of a general room is at least four and a half folds, otherwise it is impossible to avoid the combination of four corners gathered together. The thickness of tatami varies from 1.5 cm to 6 cm. Platforms with geothermal or storage functions are usually suitable for making thin tatami. There is no suitable thick tatami directly on the floor in geothermal or attic.