Kotatsu
Encyclopedia
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, often built into the table itself. Kotatsu are used almost exclusively in Japan, although similar devices are used elsewhere.
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. By the 14th century in Japan, a seating platform was introduced to the irori and its cooking function became separated from its seating function. On top of the wooden platform a quilt was placed, known as an oki
which trapped and localized the heat of the charcoal burner. This early ancestor to the modern kotatsu was called a horigotatsu. The word horigotatsu (掘り炬燵) is derived from the kanji
掘-り meaning ditch, 炬 meaning torch or fire, and 燵 meaning foot warmer.
The formation of the horigatsu was slightly changed in the Edo Period
in the 17th 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. The blanket was then again placed on top of the platform where one could sit underneath to stay warm.
The moveable kotatsu was later created originating from the concept of horigatsu. This kotatsu came about with the popular use of tatami
matting in Japanese homes. Instead of placing the charcoals in the irori, they were placed in a earthen pot which was placed on the tatami making the kotatsu transportable. This more modern style kotatsu is known as the okigotasu. The word okigotatsu (置き炬燵) is derived from the kanji 置き meaning placement, 炬 meaning torch or fire, and 燵 meaning foot warmer.
In the middle of the 20th 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. Thus, the kotatsu became completely mobile with electricity and was mainstreamed in the Japanese home.
cushions with their legs under the table with the blanket draped over the lower body. The kotatsu was designed for people wearing traditional Japanese style clothes, where the heat would enter through the bottom of the robes and exit around the neck, thus heating the entire body.
Most Japanese housing is not insulated to the same degree as a western domicile and does not have central heating
, thus relying primarily on space heating. Heating is expensive because of the lack of insulation
and the draftiness of housing. A kotatsu is a relatively inexpensive way to stay warm in the winter, as the futons trap the warm air. This is also the time of the year where many activities take place around the kotatsu, such as eating, reading, watching television, and socializing. Families may choose to concentrate their activity to this one area of the house in order to save on energy costs. In the summer, the blanket may be removed, and the kotatsu can be used as a normal table.
It is possible to sleep under a kotatsu, though unless one is quite short, one's body will not be completely covered. This is generally 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 short, so one may accidentally touch heating elements when moving while asleep, risking burns. Traditionally, children are told that they will catch a cold if they sleep under a kotatsu. However, pets such as cats frequently sleep under kotatsu 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 is often the center of domestic life. In the evening family members gather around the kotatsu to enjoy food, television, games and conversation while keeping their bottom half warm under the kotatsu. 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."
is also used in Iran
.
A very similar item called a sandali has been widely used for centuries in Tajikistan
and Afghanistan
. They are used even today in many traditional houses, as a warm family eating place.
In Spain, there is a similar item called a "mesa camilla" which is a small round table with a heater placed underneath.
In China and Korea, underfloor heating
is traditionally used instead; the devices used are respectively a Kang bed-stove
and an ondol
.
Table (furniture)
A table is a form of furniture with a flat and satisfactory horizontal upper surface used to support objects of interest, for storage, show, and/or manipulation...
frame covered by a futon
Futon
Futon is an English word derived from Japanese , a term generally referring to the traditional style of Japanese bedding consisting of padded mattresses and quilts pliable enough to be folded and stored away during the day, allowing the room to serve for purposes other than as a bedroom...
, or heavy blanket, upon which a table top sits. Underneath is a heat source, often built into the table itself. Kotatsu are used almost exclusively in Japan, although similar devices are used elsewhere.
History
The history of the kotatsu begins in the Muromachi era in the 14th century. Its origins begin with the Japanese cooking hearthHearth
In common historic and modern usage, a hearth is a brick- or stone-lined fireplace or oven often used for cooking and/or heating. For centuries, the hearth was considered an integral part of a home, often its central or most important feature...
known as the irori
Irori
Irori are a type of traditional sunken hearth common in Japan. Used for heating the home and cooking food, irori are essentially square pits in the floor with a pot hook, or jizaikagi...
. Charcoal was the primary method of cooking and heating in the traditional Japanese household and was used to heat the irori. By the 14th century in Japan, a seating platform was introduced to the irori and its cooking function became separated from its seating function. On top of the wooden platform a quilt was placed, known as an oki
Oki
-Places:*Oki District, Shimane - the Oki Islands in Japan, formerly Oki Province*Oki, Fukuoka - a town in southern Japan*Oki Islands - a group of islands in the Sea of Japan*Oki Airport - The airport serving the Oki Islands...
which trapped and localized the heat of the charcoal burner. This early ancestor to the modern kotatsu was called a horigotatsu. The word horigotatsu (掘り炬燵) is derived from the kanji
Kanji
Kanji are the adopted logographic Chinese characters hanzi that are used in the modern Japanese writing system along with hiragana , katakana , Indo Arabic numerals, and the occasional use of the Latin alphabet...
掘-り meaning ditch, 炬 meaning torch or fire, and 燵 meaning foot warmer.
The formation of the horigatsu was slightly changed in the Edo Period
Edo period
The , or , is a division of Japanese history which was ruled by the shoguns of the Tokugawa family, running from 1603 to 1868. The political entity of this period was the Tokugawa shogunate....
in the 17th 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. The blanket was then again placed on top of the platform where one could sit underneath to stay warm.
The moveable kotatsu was later created originating from the concept of horigatsu. This kotatsu came about with the popular use of tatami
Tatami
A is a type of mat used as a flooring material in traditional Japanese-style rooms. Traditionally made of rice straw to form the core , with a covering of woven soft rush straw, tatami are made in standard sizes, with the length exactly twice the width...
matting in Japanese homes. Instead of placing the charcoals in the irori, they were placed in a earthen pot which was placed on the tatami making the kotatsu transportable. This more modern style kotatsu is known as the okigotasu. The word okigotatsu (置き炬燵) is derived from the kanji 置き meaning placement, 炬 meaning torch or fire, and 燵 meaning foot warmer.
In the middle of the 20th 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. Thus, the kotatsu became completely mobile with electricity and was mainstreamed in the Japanese home.
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. The kotatsu is usually set on a thin futon, like a throw rug. A second, thicker futon is placed over the kotatsu table, above which the tabletop is placed. The electric heater attached to the underside of the table heats the space under the comforter.
- Charcoal: The more traditional type is a table placed over a recessed floor . The pit is cut into the floor and is about 40 centimeters deep. A charcoalCharcoalCharcoal is the dark grey residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood or other substances in the absence of oxygen...
heater is placed somewhere in the pit's floor, walls, or, as in the modern-style kotatsu, attached to the table-frame. There are pit type kotatsu with an electric heater too.
Use
In the 21st century, the kotatsu consists of the electric heater attached to the frame, which is no longer limited to wood but can be made of plastic and other materials. Generally, a blanket (or shitagake) is draped over the frame under the table-top. This first blanket is covered by a second heavier blanket, known as a kotatsugake (火燵掛布). Kotatasugake are often decorative and can be designed to match home décor. A person sits on the floor or on zabutonZabuton
A zabuton is a Japanese cushion for sitting. The zabuton is generally used when sitting on the floor, and may also be used when sitting on a chair. Ordinarily any place in Japan where seating is on the floor will be provided with zabuton, for sitting comfort...
cushions with their legs under the table with the blanket draped over the lower body. The kotatsu was designed for people wearing traditional Japanese style clothes, where the heat would enter through the bottom of the robes and exit around the neck, thus heating the entire body.
Most Japanese housing is not insulated to the same degree as a western domicile and does not have central heating
Central heating
A central heating system provides warmth to the whole interior of a building from one point to multiple rooms. When combined with other systems in order to control the building climate, the whole system may be a HVAC system.Central heating differs from local heating in that the heat generation...
, thus relying primarily on space heating. Heating is expensive because of the lack of insulation
Thermal insulation
Thermal insulation is the reduction of the effects of the various processes of heat transfer between objects in thermal contact or in range of radiative influence. Heat transfer is the transfer of thermal energy between objects of differing temperature...
and the draftiness of housing. A kotatsu is a relatively inexpensive way to stay warm in the winter, as the futons trap the warm air. This is also the time of the year where many activities take place around the kotatsu, such as eating, reading, watching television, and socializing. Families may choose to concentrate their activity to this one area of the house in order to save on energy costs. In the summer, the blanket may be removed, and the kotatsu can be used as a normal table.
It is possible to sleep under a kotatsu, though unless one is quite short, one's body will not be completely covered. This is generally 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 short, so one may accidentally touch heating elements when moving while asleep, risking burns. Traditionally, children are told that they will catch a cold if they sleep under a kotatsu. However, pets such as cats frequently sleep under kotatsu 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 is often the center of domestic life. In the evening family members gather around the kotatsu to enjoy food, television, games and conversation while keeping their bottom half warm under the kotatsu. 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."
Other countries
A similar product called a korsiKorsi
A Korsi is a type of low table found in Iran, with a heater underneath it, and blankets thrown over it. It is a traditional furniture of Iranian culture....
is also used in Iran
Iran
Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...
.
A very similar item called a sandali has been widely used for centuries in Tajikistan
Tajikistan
Tajikistan , officially the Republic of Tajikistan , is a mountainous landlocked country in Central Asia. Afghanistan borders it to the south, Uzbekistan to the west, Kyrgyzstan to the north, and China to the east....
and Afghanistan
Afghanistan
Afghanistan , officially the Islamic Republic of Afghanistan, is a landlocked country located in the centre of Asia, forming South Asia, Central Asia and the Middle East. With a population of about 29 million, it has an area of , making it the 42nd most populous and 41st largest nation in the world...
. They are used even today in many traditional houses, as a warm family eating place.
In Spain, there is a similar item called a "mesa camilla" which is a small round table with a heater placed underneath.
In China and Korea, underfloor heating
Underfloor heating
Underfloor heating and cooling is a form of central heating and cooling which achieves indoor climate control for thermal comfort using conduction, radiation and convection...
is traditionally used instead; the devices used are respectively a Kang bed-stove
Kang bed-stove
The Kang is a traditional long sleeping platform made of bricks or other forms of fired clay and more recently of concrete in some locations. Its interior cavity, leading to a flue, channels the exhaust from a wood or coal stove...
and an ondol
Ondol
An ondol, also called gudeul, in Korean traditional architecture, is underfloor heating which uses direct heat transfer from wood smoke to the underside of a thick masonry floor...
.