Kotatsu
炬燵（こたつ）

Kotatsu is usually described as a low table which has heat source on the back side and is covered with a blanket. There is similar traditional furniture called 'korsi' in Middle East. Its origin dates back to Muromachi period (1336 - 1573). In those days, kotatsu could not be moved. People put a duckboard on irori, a Japanese traditional fireplace, covered it with some clothing, and kept warm. As time passed, they used hibachi or a brazier as heat source and covered it with futon or a comforter. At this time, kotatsu became portable. One theory says, as Tsurezuregusa or Essays in Idleness suggests, Japanese houses were traditionally designed for summer, and it was too cold even inside houses in winter.

In Meiji era (1868 - 1912), Western cultures were introduced into Japan, including space heaters. They needed gas, oil, or electricity. There appeared electric blaziers or denki hibachi. In the late Meiji era, it is said that a British studio potter and art teacher, Bernard Leach, had hori gotatsu made in his house for the first time ever. He wanted to use kotatsu to keep warm while seated with his legs stretched out. An ordinary kotatsu is put on a flat floor; however, hori gotatsu means a low table with heat source put over a hole in a floor so that people can stretch out their legs like being seated on a bench.

In the early Showa era (1926 - 1989), kotatsu with electric heat source, or denki kotatsu, started to be sold by Matsushita Denki (Panasonic today). It looked like a box with a cord. In 1933 denki kotatsu with a low table stated to be sold, but it did not become widespread in those days. In 1957, when high economic growth was seen in Japan, Toshiba started to sell denki yagura kotatsu, which was a prototype of today's kotatsu. Kotatsu with a low table was not common until then.

Many of kotatsu used to have a red lamp under the table, which made people feel warm visually and know whether it was turned on or off. These days, people do not stick to the color, and the number of this type decreased.

One figure (https://tbs-mri.com/n/nc64bc777fdfd) shows, 93% of Japanese families had kotatsu in their house; however, the percentage has been gradually declining. Nevertheless, koatsu evolved during the Covid-19 pandemic. Many people work remotely in their house and use kotatsu, which can contribute to saving money for electricity as well.

In addition, people enjoy experiencing kotatsu culture these days; in winter, some restaurants, cafes, or shopping malls prepare kotatsu seats. They have a good time with their friends or family while gathering around and keeping warm in kotatsu.