“Irori” is a device installed in the room for handling open flames, and has been used for heating, cooking, lighting, and other purposes. As the Japanese kanji means, it’s a square fire pit inside the house.

Charcoal is basically used as fuel so that there is not much smoke, but firewood was also used in some cases. This smoke was used to make smoke, and by smoking the house itself, it also had the effect of prolonging the life of the house.