A Japanese room is measured, not by feet and inches, but by the number of mats it contains. A mat consists of a straw mattress, about an inch and a half thick, with a covering of fine matting which is sewn on at the edges of the mattress either by itself or with a border, usually dark-blue and an inch wide, of coarse hempen cloth. It is six feet long by three wide; this measure is not always exact, but may vary by an inch or more in either direction. When a house is newly built, the mat-maker comes to make mats to fit the rooms in it. But in spite of the variation, the size of a room is always given in the number of mats it holds, so that we never know the exact dimensions of a room. The smallest room has two mats, that is, is about six feet square; the next smallest is three-matted, or three yards by two. Four-matted rooms are sometimes to be found; but such rooms are unshapely, being four yards long by two wide. A room with four and a half mats is three yards square and has the half mat, which is a yard square, in the centre. The next size is six-matted, or four yards by three and is followed by the eight-matted, or four yards square.