Kotatsu

The kotatsu is a Japanese comforting object, a lifesaver that keeps you warm in the cold seasons and is the focal point of the house in cold weather. Like a campfire that draws people (and cats) around, it is a source of warmth and joy that brings people together.

Usually placed in the center of the house, the modern kotatsu consists of a low table on which a special futon blanket is placed. An electric heater is attached underneath, which keeps the lower body warm. Although they enjoyed some popularity at one point after underfloor heating became more common, the Japanese concept of the kotatsu has taken off in an attempt to save energy as they are cheaper to run than electric heat.

Origins of the Kotatsu 

The history of kotatsu begins in the Muromachi period (corresponding to the 14th century). Its origins derive from the typical Japanese cooking system known as irori, which involves a built-in hearth in the center of a room covered with tatami mats. From the 14th century, seating was introduced around the irori, separating its functions of cooking food from that of a gathering place for family members. A quilt (called an oki) was placed on top of a wooden structure placed over the irori that trapped and localized the heat from the brazier underneath the structure. This primordial ancestor of the kotatsu was called horigotatsu. The Japanese word horigotatsu (掘り炬燵) results from the union of the kanji 掘-り (pit, hole), 炬 (torch or fire), and 燵 (foot warmer).

The construction of the horigatsu was slightly changed in the Edo period, in the 17th century. These changes involved the floor around the irori, where a square-shaped hole began to be made around the brazier. The wooden structure of the horigatsu was placed around this hole, forming a hearth. The blanket was placed on top of the structure at all times, creating a warm place where it was possible to put one's legs once seated.

kotatsu-origins

Movable kotatsu were later created from the concept of horigatsu, and they became widespread due to the common use of tatami mats in Japanese homes. The coals were no longer placed inside the irori but inside a crock pot that was placed on the floor; in this way it was possible to place the kotatsu wherever one wanted. This model of kotatsu is known as okigotasu. In the Japanese language, the word okigotatsu (置き炬燵) is derived from the union of the kanji 置き (place), 炬 (torch or fire), and 燵 (foot warmer).

In the mid-20th century, electricity replaced coal as a heating source, and it became possible to attach an electric heating element to the structure of the kotatsu instead of using the earthenware brazier. In this way it became easy to move the kotatsu as desired, and this contributed to its widespread use in Japanese homes.

Nowadays, kotatsu consists of an electrical heating element attached to the table frame, which can be made of plastic or other materials in addition to traditional wood. Usually a blanket is draped around the frame under the table top. This blanket is covered by a second, heavier blanket, which is called a kotatsugake (火燵掛布). Kotatasugake often have a decorative function, and can be designed to match the decor of the home. For warmth, one sits on the floor or on zabutons, placing the legs under the table with the lower part of the body wrapped around the kotatsugake. The kotatsu was designed with traditional Japanese clothing in mind, allowing heat to enter through the lower part of the clothes and exit through the neck, thus being able to warm the whole body.

japanese-home-kotatsu


Most Japanese homes are not thermally insulated as effectively as Western homes and do not have central heating systems to heat the various rooms. Heating the house is very expensive, both because of insufficient thermal insulation and exposure to drafts in the apartments. The use of kotatsu provides a relatively inexpensive source of heat to rely on during the winter months, taking into account that futons are able to retain warm air. Households may choose to concentrate their activities in the room where the kotatsu is placed to save on energy costs. In the summer season, the blanket is removed and the kotatsu can be used as a regular coffee table.

It is possible to sleep under kotatsu, although normally a person's body (unless they are quite short) is not completely covered by the futon. Sleeping under the kotatsu is considered acceptable for naps, but it is not ideal for sleeping at night for several reasons: the body is not completely covered and is heated unevenly; the table is short and it is possible to accidentally touch the heating elements by moving around during sleep, exposing oneself to the risk of burns. Children are told that if they sleep under a kotatsu they will catch a cold; however, it is common for pets (such as cats) to sleep under kotatsu by being able to stand with their whole body inside the blanket-similar to cats sleeping near underfloor heating vents in Western countries (Japanese homes do not have this type of heating).

During the winter months in Japan, the kotatsu is often the center of family life. In the evenings, family members gather around the kotatsu to eat, watch television, play games, and converse while keeping their legs warm under the kotatsu.

Translated with www.DeepL.com/Translator (free version)

How did kotatsus evolved over time?

Traditional Japanese homes have always been difficult to heat because of their thin walls. So it's not surprising that kotatsu has become an enduring and well-established part of Japanese culture.

Of course, heating other rooms in the house, especially the bedroom, became more desirable and so the portable kotatsu was born.

First coals in an earthen pot, then later an electric heater attached to the bottom of the table, making it portable, the wonderful opportunity to take a nap under your kotatsu was born. This modern style is called oki-gotatsu, oki meaning placement.

How does a Kotatsu work?

A kotatsu table works very easily. It is a low wooden table, into which a blanket (shown here in green) is wedged between the base and the top.

how-kotatsu-work
The heater, or kotatsu heater, is fixed directly under the table. The heater is specially designed for these models of heated furniture. It provides continuous gentle heat without the risk of burning. With this type of heater combined with a good blanket, you stay warm and cozy all day long.

The oldest models are dug in the ground, to allow the burning of coal. This kind of system is no longer found in modern houses. However n traditional Japanese houses, you can still come across them.

old-kotatsu

The Kotatsu Table 

Japanese kotatsu tables are a style of decoration that conveys the traditional values of honor, duty and love for nature. In fact, kotatsu tables are the most common tables used in Japan and is a piece of furniture with multiple functions.

With a kotatsu table, you will have the simplicity and originality of Japanese style induces well-being and joy of living. It perfectly creates a serene and Zen atmosphere in your interior.

kotatsu-table

These tables are not simply for use along the other items that complete the kotatsu but can also be utilized as a traditional tea and coffee table when the sunny days come by. which makes them a great versatile piece of furniture.

The Kotatsu Futon

A Kotatsu is always wrapped with a blanket, most frequently referred to as Futon. The unique thing about the kotatsu is the fact that underneath it is a heat source. This heat source is covered by a Futon and can be built-in or detached from the table. Kotatsu's modern design mainly utilizes an electric heater. On the other hand, the traditional Kotatsu style is based on charcoal heating.

kotatsu-futon-blanket

How does the Futon stays in place on the Kotatsu?

Usually, the top of a Kotatsu beneath which a futon is tucked is not stationary and is primarily kept in place by the weight of the top itself. There are underpads that can be acquired to assist in holding the board in place. Alternatively, the board can be held in place with screws, but this involves drilling holes in the futon underneath, so it is not a very practical option.

What makes a Kotatsu so great?

The first benefit of a kotatsu is undoubtedly its comfort. Indeed, what could be more pleasant than to warm up in front of a movie or a delicious warm meal like nabe or ramen.

Additionally, this piece of furniture creates a friendly atmosphere, even outside of mealtime. In Japan, the whole family meets in the evening to do homework, have dinner, play together or watch a TV show.

kotatsu-blanket
We can add that this style of furniture, although common in Japan, will not lack originality at home. It is an atypical piece of furniture, which will surprise your friends!

As we have seen earlier, the kotatsu heater is energy-efficient and an economical solution for heating. You can use this system to stay warm, without having to heat a whole room. Great savings in perspective. And best of all your fur babies won't leave it! 

cat-kotatsu

dog-kotatsu

Finally, we can say that in addition to the above-mentioned advantages, the kotatsu table also has a very practical side. Depending on the one you choose, you can use it all year round. All you have to do is remove the small heater and the cover when the weather is fine. You can then use it as a traditional coffee table.

The piece of furniture that warmed entire generations

Consisting of a low table under which an electric heater heats up and the whole thing is covered with a thick blanket called futon, the kotatsu is widely used in Japanese homes where the family gathers to eat, read or watch TV.

It allows to keep the heat in a cold room. In Japan, the houses are not all well insulated yet, so it can be very cold in winter in some rooms due to the architecture of Japanese homes.

japanese-kotatsu

Developed in the 14th century, the kotastu consisted of a fireplace dug into the floor of the house called irori. This fireplace was covered with a table and a blanket to contain the heat. Rather dangerous, with the very frequent fires, the fire is replaced by coal.

It is only with the emergence of electricity and electric heating appliances that the system evolved in the 20th century. The heating system is placed directly under the table and can now be plugged in anywhere.

The Kotatsu of today is much more design thought, round, square, extended to fit your interior decoration. Some kotatsu tables are even made to order.