thumb|A modern Japanese kotatsu

thumb|The underside of an electric kotatsu, with the heater visible in the centre

thumb|[[Edo period|Edo-period kotatsu at the Fukagawa Edo Museum]]

A is a low, wooden table frame covered by a futon, or heavy blanket, upon which a table top sits. Underneath is a heat source, formerly a charcoal brazier but now electric, often built into the table itself. Kotatsu are used almost exclusively in Japan, although similar devices for the same purpose of heating are used elsewhere, e.g. the Spanish brasero or Iranian korsi.

History

The history of the kotatsu begins in the Muromachi period or Ashikaga shogunate during the fourteenth century. Its origins begin with the Japanese cooking hearth, known as the irori. Charcoal was the primary method of cooking and heating in the traditional Japanese household and was used to heat the irori. This early ancestor to the modern kotatsu was called a hori-gotatsu. The word hori-gotatsu () is derived from the kanji (hori) meaning ditch, digging, (ko) meaning torch or fire, and (tatsu) meaning foot warmer.

The formation of the hori-gotatsu was slightly changed in the Edo period during the seventeenth century. These changes consisted of the floor around the irori being dug-out into the ground in a square shape. The wooden platform was placed around this, making a hearth. Then the blanket was placed on top of the platform again, where one could sit with legs underneath to stay warm.

In the middle of the twentieth-century charcoal was replaced with electricity as a heating source. Instead of having the moveable earthen pot of charcoals beneath the kotatsu, it was possible to attach an electric heating fixture directly to the frame of the kotatsu. By 1997, the majority (approximately two-thirds) of Japanese homes had the modern irori and 81 percent had a kotatsu, though they are warmed using electricity instead of glowing coals or charcoal. Thus, the kotatsu became completely mobile with electricity and became a common feature of Japanese homes during winter.

Types

There are two kinds of kotatsu used in Japan today, differing in the configuration and the type of heating:

  • Electric: The modern style of kotatsu, , consists of a table with an electric heater attached to the underside of the table. This evolved from a clay pot with hot coals placed under a table. In the summer, the 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

thumb|Persian korsí

There are similar economical and often sociable systems to keep warm while sitting still in countries around the world. 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. During World War I, British Royal Engineers built 'Japanese footwarmers' in the trenches.

The 18th-century traveler Lady Mary Wortley Montagu describes the similar tendour in her Turkish Embassy Letters.

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. Romans used a hypocaust for underfloor heating.

See also

  • Chabudai, a short-legged table used in traditional Japanese homes
  • Electric blanket
  • Hibachi, a traditional Japanese heating device
  • Korsi
  • Passive house

References