JAPANESE CULTURE, EXPLAINED
こたつ
A kotatsu holds heat beneath a quilt-covered frame. In a common modern form, an electric heater sits under a low table, with a removable tabletop resting above the quilt.
A common electric kotatsu has a quilt draped over its frame, a separate tabletop above it and a heater fixed underneath. The quilt holds warmth around people’s legs, leaving the tabletop free for use. It warms this enclosed space rather than the whole room.
Floor-standing: a continuous floor
Recessed: space below floor level
A horigotatsu has a recess for the legs; an okigotatsu stands on the floor. Either floor arrangement can be described separately from the heat source: historical kotatsu used charcoal, while later forms use electricity.
Fukuyama’s museum displays two charcoal-heated furnishings. A hibachi is an open container of ash and charcoal for warming hands or supporting a kettle. Its okigotatsu encloses a brazier beneath a quilt-covered frame, allowing several people to warm their legs from different sides.
Kamagaya’s museum traces possible origins to Muromachi and wider use to Edo. Frames over hearths were followed by movable charcoal versions; Urayasu’s museum links their spread to cotton bedding. Electric kotatsu heaters were sold in 1924, followed in 1957 by a table-frame electric model.
The 1957 design had a mesh-guarded nichrome heater, a downward reflector and a thermostat. Toshiba also insulated the upper part and made the frame from magnolia, a workable wood resistant to splintering. Metro’s explanation of modern thermostat control describes the heater switching off as temperature rises and on again as it cools.
Modern thermostat operation, as explained by Metro. Metro: temperature control
Infrared-lamp models arrived in 1960. Electronic control introduced in 1970 allowed continuous adjustment and made temperature cycling less noticeable than with earlier thermostat control. Later fan models circulated warm air. From 1975, furniture-style designs could serve as tables throughout the year.
Young people share a kotatsu in Harunobu’s Narcissus. In Sukenobu’s 1731 Ehon Tokiwa-gusa, readers gather with open books close to the quilt. The library’s other examples show conversation around a kotatsu and one aboard a pleasure boat. The pictures show how people used the warm space, while the heat source remains hidden.
The upper heater directs warmth down into a quilt-enclosed space, while the tabletop remains available above.
It offered continuous adjustment with less noticeable cycling, rather than adding temperature control to an uncontrolled heater.
An open hibachi allows hands near the heat; a quilted frame encloses space for several people’s legs.
