Kotatsu

The only heating available in the old traditional Japanese houses was a portable fireplace called hibachi, a heat-resistant pot filled with charcoal embers.

But the heat was quick to dissipate in the cold surrounding air, so kotatsu, an ingenious setup was invented: a table covered by a futon was placed over the fire source, and the people were able to sit with the legs underneath the table.

Over the time the design of kotatsu was improved, and today they are still popular, being made with electric heaters.