Irori – The Japanese Hearth

Now that winter is coming and the weather forecast showed the symbol for snow here in Tokyo it might be interesting to talk about heating. This is the season where many foreigners (and indeed many Japanese) wonder aloud how Japanese homes can be so fantastically cold. The discussion usually involves plenty of curse words unfit for reproducing on a family blog like this! Foreigners usually wonder why Japanese homes aren’t better insulated. In northern Japan, including all of Hokkaido and large parts of the northernmost prefectures, insulated western style homes, complete with double or triple glazing, is the norm. In the rest of Japan you will very rarely find insulation in homes. One of the reasons for this is that insulation is basically for heated homes, and Japanese homes generally aren’t heated. While westerners use huge amounts of resources to ensure they have comfy homes at a perpetual 20 degrees no matter the season, Japanese are used to the old idea of heating only the people inside the house, although this is changing and more and more people heat their homes.

I remember some mornings in my first home in Tokyo, a rickety old three story wooden framed stick building where it was so cold that I found ice on the glass of water left beside my bed. The common feature in almost all Japanese homes is the kotatsu, a low table covered in a thick skirt and heated underneath, trapping all the heat inside and keeping the entire family gathered around it with their lower bodies comfy and warm and all bundled up in warm clothes on their upper bodies. This is such a universal feature in Japanese life that countless Japanese customs can be explained by observing how a family use their kotatsu in winter. Almost every family you talk to will have similar stories of refusing to leave the kotatsu and taking turns to get up for errands like changing the channel on the TV or getting mikan fruit from the kitchen. You will also get stories of whole families sleeping around the kotatsu rather than going up to their freezing bedrooms. There is even plenty of room for romance and fun around the kotatsu, for young and old couples. Any Japanese book, manga, anime or TV show depicting family life will have these kotatsu-scenes.

But before the kotatsu there was the irori, the Japanese hearth. It is a sunken hearth in the middle of the traditional Japanese living room, filled with fine sand and ashes. Contrary to common sense it is always made of wood, the sand protecting the fire-hardy pear tree heartwood from burning. It might seem counter-intuitive, but the Japanese have managed to invent a way to keep an open fire in a wooden fire pit inside a wooden house with paper doors and straw mat floors, in an ecological, economical and healthy way! The irori has many uses. It heats the room, it provides a spot to grill, cook or bake simple food. You can heat or boil water. It lights the room and keeps the fire alive throughout the night which was handy before matches or lighters. It dries clothes. It gathers the family and helps communication. It shows family hierarchy and provides a simple symbol of stability. It dries the timbers of the house, preventing rot, fungus and wood disease, preserving the house for hundreds of years (there is even one wooden house that has been continuously inhabited for over 1000 years).

In the old days when the smoke of the indoor fire was important for preserving the thatched roof of all homes, it was common to use both firewood and coal, but as people get more prosperous they prefer the smoke-less coal. In the old days people were free to pick fallen branches and harvest fallen logs but were not allowed to cut living wood, so it was easy to gather enough fuel for the irori. Making coal however was an extra step in the process and although an easy and simple job it was not possible for many families to gather enough wood or bamboo to make coal.

To stop sparks many irori had a woven mat hung over them, which could be used to dry fish, forage and fruit for preservation, but the classical irori always had a jizakagi, a hollow bamboo pole suspended from the ceiling containing a metal rod or chain, with a hook at the end. The jizaikagi is the most important tool in using the irori. It has a lever that is usually in the form of a fish, that allows you safely regulate the hight of the hook and how close your food or pot is to the fire.

Why the fish form? There are two often recited reasons for this. The fish being a water creature, is symbolically protecting against the fire of the hearth, thus preventing accidents and house fires. The other reason is related to the first, in that fish having no eyelids were thought to never sleep, which is a good ability to have if you are guarding a fire.

This irori and the old men volunteering to tending the fire is inside a beautiful old house at the Edo-Tokyo Open Air Architectural Museum (江戸東京たてもの園), in Koganei, western Tokyo. The last photo is of the inside of the house, very thin walls and absolutely no insulation even in the middle of winter.