blanket may be removed, and the kotatsu used as a normal table. It is possible to sleep under a kotatsu, although unless one is quite short, one's body will not be completely covered. This generally is considered acceptable for naps, but not for overnight sleeping for many reasons: one's body is not completely covered, yielding uneven heating; the table is low, so one may touch heating elements accidentally when moving while asleep, risking burns. Traditionally, children are told that they will catch a cold if they sleep under a kotatsu. Pets such as cats frequently sleep under kotatsu, however, and are small enough to fit completely underneath—comparable to cats who sleep on floor heating vents in Western countries (Japanese homes do not generally have floor heating vents). During the winter months in Japan, the kotatsu often is the center of domestic life. In the evening family members gather around the kotatsu to enjoy food, television, games, and conversation while keeping the lower half of their bodies warm. It has been said that "once under the kotatsu, all of your worries slip away as a familiar warmth takes over and you become completely relaxed." Historically, were made of bast fibers. Later, cotton was introduced (1300s to 1700s, depending on region) and they were usually made of bast-filled quilts of recycled cotton, dyed with indigo and pieced from old garments in boroboro style. , for going under the , as a floor covering, were made the same way. In the 2010s, kotatsu-gake were often decorative and might be designed to match home décor. Other countries There are similar systems in countries around the world: economical and often sociable ways to keep warm while sitting still. In Spain and Portugal, the is a small round table with a brasero heater (i.e. a brazier) placed underneath. The Netherlands used to use a foot stove. In the First World War, British Royal Engineers built 'Japanese footwarmers' in the trenches. Tajikistan and Afghanistan have the very similar sandali, used even today in many traditional houses as a warm family eating place. Another similar item called the korsi is used likewise in Iran. In China and Korea, underfloor heating traditionally is used. The devices used in a similar fashion are, respectively, a Kang bed-stove and an ondol. See also Chabudai, a short-legged table used in traditional Japanese homes Hibachi, a traditional Japanese heating device Electric blanket Korsi