In a traditional Japanese house, you don't sit on chairs or sleep on beds. You sit and sleep on the floor using cushions and futon bedding. The way the Japanese room is designed makes this possible; it evolved over time as an extension of the way people live and as an expression of the native culture.
Even today, when Western-style rooms with chairs and beds are common, most houses have at least one room in the traditional style.
The biggest feature of the Japanese room is that the floor is made of tatami (rush matting). The mats are rectangular and measure around 1.7 square meters (about 18 square feet); the number of tatami mats is usually the way the size of rooms is measured.
Before Western-style houses became common, the Japanese room was partitioned with sliding, paper-screens called shoji or fusuma instead of doors and windows. During the daytime the traditional Japanese room serves as a living and dining room, and at night, it can be used as a bedroom by laying out the futon. The futon is folded up in the morning and stored in the oshi-ire (closet).
The room for guests is called the zashiki, which usually has a small alcove (tokonoma) with a slightly raised floor. A work of calligraphy is displayed in the center of the alcove, and a seasonal ikebana (cut flower) arrangement or other ornament is placed on the floor. Dolls to mark special traditional occasions are also sometimes placed in the tokonoma.